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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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2

Resilient Design and Multifunctional Materials

Workshop Co-Chair Ajay Malshe, the R. Eugene and Susie E. Goodson Distinguished Professor of Mechanical Engineering at Purdue University, welcomed panelists and participants to the first day of the workshop series, which was motivated in part by the National Academies of Sciences, Engineering, and Medicine’s publication Fostering the Culture of Convergence in Research (NASEM, 2019) and the notion that the future of combat is an asymmetric techno-socio-economic problem, solutions for which seek convergence. He highlighted ongoing nationwide initiatives to develop a convergent manufacturing platform and described a vision for the future to deliver agile, resilient, and versatile advanced solutions in a unified manufacturing platform for the mission, equipped with the convergence of designs, materials, tools, and processes to augment soldiers’ functionality for combat and to reduce dependency on supply chains for critical materials and their applications. Traditional manufacturing processes are discretized in terms of their applicability and material-specific process optimization; have limited adaptability in terms of materials and design configurations; and require assembly, finishing, and packaging with separate sequential processing steps, increasing overall cost and turnaround time for logistics (see Bapat et al., forthcoming). Therefore, he asserted that the vision for the future could be achieved with convergence by hybridization in manufacturing to deliver at the point of need.

Malshe defined convergent manufacturing as a unified manufacturing system platform that converges heterogeneous interfaces in design, materials, processes (e.g., additive, subtractive, and transformative), and diagnostics with physical sensor data and digital models as inputs to produce functional devices, components,

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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and complete systems as outputs at the point of need. Key attributes of such a platform include modularity, flexibility, connectivity, reconfigurability, portability, and customization. He emphasized that convergence in a unified manufacturing platform enables progress beyond Industry 4.0,1 with the use of digital and physical footprints in designs from nature, heterogeneous critical materials2 for multifunctionality, manufacturing tools for resilience, manufacturing processes for agility, and a sensor network for detection of critical interfaces (see Malshe et al., 2021). He stressed that these critical interfaces—for example, physical–digital interfaces,3 design for manufacturing, and heterogeneous material interfaces4—cannot be removed and need to be managed carefully.

Malshe encouraged panelists and participants to consider the following three questions throughout the workshop series: (1) What is your vision of convergent manufacturing, according to your expertise and experience? (2) What are the knowledge gaps for science, engineering, and implementation of convergent manufacturing? (3) What are one or two “moonshot” projects for convergent manufacturing?

DEFENSE TECHNOLOGY

Maj. Gen. Darren L. Werner, Commanding General, U.S. Army Tank-automotive and Armaments Command (TACOM), Army Materiel Command

Keynote speaker Maj. Gen. Werner explained that TACOM synchronizes, integrates, and delivers soldier and ground systems and readiness solutions to ensure that the Army is equipped appropriately. TACOM’s mission emphasizes the sustainment of equipment after it has been developed, produced, acquired, and fielded. When the U.S. Department of Defense’s (DoD’s) National Defense Strategy was released in 2018, the United States was “emerging from a period of strategic atrophy,” in which its competitive military advantage had been eroding.

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1 Known as “Industry 4.0,” the Fourth Industrial Revolution is characterized by the application of information and communication technologies to industry. It builds on the developments of the Third Industrial Revolution that began in the 1970s in the 20th century through partial automation using memory-programmable controls and computers.

2 “Critical materials” here is intended as the materials that can produce the wanted multifunctionality.

3 Physical–digital interfaces are, for example, the sensors that detect the properties of a material and any defects that occur in the material and communicate that information to the computational model for adjustments in the manufacturing process. In a convergent platform, these are intrinsic to the platform operating and cannot be removed, they must instead be carefully managed.

4 Heterogeneous material interfaces will occur in the product being manufactured when the materials are changed from one composition to another and are an intrinsic fact of the change itself and cannot be removed, they must be managed.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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During the same year, the Department of the Army released its Army Additive Manufacturing Campaign Plan, which developed an overarching strategy and provided a framework to operationalize the full potential of an additive manufacturing capability that is synchronized and integrated across the enterprise and has the potential to enhance mission readiness from the tactical point of need—to improve production, maintenance, and sustainment within the organic industrial base5 (i.e., “from the foxhole to the factory”) and to support modernization efforts through advanced science and technology development to make better materials. He remarked that the Army is on the verge of a transformation as it reimagines the sustainment of current and next-generation platforms for future operations (e.g., acquisition processes, location of pre-positioned forward stocks, forward repair activities, maintenance connectivity and self-diagnosis, prognostics and predictive maintenance, new approaches such as additive manufacturing, and agility in part development and production).

Reflecting on innovative efforts to institutionalize additive manufacturing, Maj. Gen. Werner mentioned the Army’s recognition that the evolution from traditional manufacturing (which operates in separate siloes according to manufacturing method and material) to convergent manufacturing (which combines virtual manufacturing, manufacturing processes, process monitoring and control, and heterogeneous materials in one platform to yield functional devices and components) is under way. He emphasized the value of employing new technologies to deliver enhanced capabilities quickly to soldiers. Convergent manufacturing allows for greater flexibility in part quantity and availability on the shelf and in the field as well as improvements in part characteristics to make them available, durable, and better performing in adverse situations. Convergent manufacturing is a key objective for the Army over the next 15 years, which could be realized with the ongoing automation of traditional manufacturing industrial practices and by combining multiple technologies into a single robust and agile manufacturing capability. He asserted that with the convergence of digital and physical manufacturing domains, integration of traditional manufacturing and hybrid manufacturing, advanced manufacturing, intelligent design philosophies, improved digital enterprise, virtual manufacturing, automation, and improved quality inspection, systems could be more capable and available to address multidomain objectives.

Maj. Gen. Werner posited that the Army of 2028 will be ready to deploy, fight, and win decisively against any adversary, any time, and any place in a joint multidomain, high-intensity conflict. Employing modernized systems (e.g., manned and unmanned ground combat vehicles, aircraft sustainment systems, and weapons

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5 The Army Organic Industrial Base (AOIB), a subset of the larger defense industrial base, is composed of resource providers, acquisition and sustainment planners, and manufacturing and maintenance performers.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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coupled with robust combined arms formations and tactics based on the Army’s strategic doctrine) and engaging exceptional leaders and soldiers could help the Army to achieve this vision. He stressed that the Army’s efforts should be integrated across the domains, with a balanced focus on completing current missions and modernizing for the future. Readiness—including for supply availability, equipment materials, and data—ensures that the industrial base can execute safe, reliable, repeatable, and effective solutions.

Maj. Gen. Werner noted that the Army is shaping convergent manufacturing to support a multidomain framework with continued research and design philosophies that enable the manufacturing of complex shapes and functional devices; a focus on mission tailorability and mass customization of future systems; continued investment in and development of digital manufacturing and advanced manufacturing technologies; implementation of tools that allow for production of what is needed, where it is needed, and when it is needed; provision of new technologies that allow for improved fabrication at the point of need for soldiers; and transition of new technologies to the organic industrial base.

TACOM set the following two strategic goals to support the Army’s 2018 Additive Manufacturing Campaign Plan: (1) augment supply chain responsiveness in the strategic support area now to produce parts used in the organic industrial base and (2) empower forward6 advanced manufacturing capability of the future Army to produce limited-use field parts at the tactical point of need in the operational and tactical support area as technology develops, reducing the sustainment tail7 while increasing readiness. TACOM developed the following three lines of effort to achieve these objectives:

  1. Component echelon—the main effort in which the demand signal is associated with the part, and the end state is augmenting the DoD supply chain based on current need.
  2. System echelon—a supporting effort in which the part has historical demand but is not currently on backorder status, and the end state is to qualify, store, and be prepared to deliver the part.
  3. Program echelon—a supporting effort that includes program executive office engagement, contract language, and new programs that identify parts to leverage advanced manufacturing capability today; the end state is to support modernization and future transition to sustainment requirements.

These efforts are driving TACOM and Army Materiel Command forward in the strategy for convergent manufacturing. Maj. Gen. Werner pointed out that there is

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6 The word “forward” is used here to indicate the capability to be deployed at the point of need.

7 Tail here being the supporting logistics for the effort.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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significant opportunity to experiment, evaluate, and determine how best to deliver readiness to the Army using advanced manufacturing and additive manufacturing. Advanced manufacturing and convergent manufacturing are critical to the strategic effort to modernize the organic industrial base for sustainment of current and future Army platforms. The organic industrial base is challenged to continuously modernize and flex to support manufacturing processes—scale is an imperative part of this “critical path,” he continued.

TACOM has several sites generating lessons learned related to readiness. As certification, qualification, and production efforts expand, it will be possible to integrate additive and advanced manufacturing and technical data requirements into future systems and production lines at all TACOM arsenals and depots. Maj. Gen. Werner envisioned that the Red River Army Depot, which serves as an Army Center of Industrial and Technical Excellence, could one day print parts on-demand to sustain a re-manufacturing line—the potential impact on the TACOM portfolio would be substantial, from water and fuel systems, to cannon tubes, to combat vehicles, to the tactical fleet. As the Army modernizes and sustains its legacy fleets, it is crucial that the industrial base is empowered to provide fluid and adaptable manufacturing methods, which could be achieved by applying creative and critical thinking to all processes and promoting new partnerships and enduring relationships. He said that doing this efficiently and effectively requires understanding Army operational requirements and synchronizing capabilities and resources to develop and deliver flexible and responsive support. Although this concept is simple, it is very difficult to execute. One approach would be to leverage advanced technologies across the entire Army organic industrial base to complement traditional manufacturing when the need arises. The Army would continue its effort to develop and integrate new manufacturing capabilities as well as to modernize its organic industrial base—Army Materiel Command plans to invest $5.2 billion over the next 15 years to modernize depots, manufacturing capabilities, physical and network infrastructure, and supply chain and distribution systems.

In closing, Maj. Gen. Werner commented that TACOM’s most valuable asset is the tens of thousands of people who support its arsenals and depots as well as manage the supply chain. TACOM strives to build an environment where soldiers and Army civilians are empowered to be creative as well as to develop competent leaders with the skills to foster the enduring interagency relationships that are essential to wise decision making for future operations. TACOM continues to add new skillsets (e.g., data scientists, computer programmers, researchers) to complement its current team.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Question and Answer Session

Workshop Co-Chair and Session Moderator Tom Kurfess, Chief Manufacturing Officer, Manufacturing Demonstration Facility, Oak Ridge National Laboratory, asked about approaches that should be considered for convergent manufacturing. Maj. Gen. Werner replied that Detroit Arsenal is located in the heart of advanced and convergent manufacturing and the mecca of thought on the integration of technologies into manufacturing processes; both small and large businesses are actively fusing different capabilities. Because additive manufacturing is complementary to the Army’s existing manufacturing processes, the Army has been leveraging it for prototyping (but not yet for production). Engineers have re-engineered older systems and programs using only additive manufacturing to improve output. Engineers are also developing new ways to better produce parts and systems in combat platforms and to use industrial control networks and technology to evaluate quality from the beginning of the production process to identify and eliminate flaws early in the manufacturing process. That level of capability has not yet been achieved in the organic industrial base, he explained. Other technologies, such as electrochemical machining, electrochemical deposition, and cold spray, are being applied in new ways for the defense industry. He emphasized that connecting machines is a top priority, as industrial control networks provide deeper understanding and better results.

Compiling several participants’ questions, Kurfess inquired about the role of the digital thread8 in enabling advanced capabilities. Maj. Gen. Werner suggested first developing acquisition strategies and contracts that allow the Army to access technical data that enable the integration of part manufacturing in forward locations. Next, it is important to identify which technical data are needed to create digital threads for particular parts so as to maintain a cost-effective process. He described an initial program with an infantry combat vehicle (M113) as a platform to develop a digital twin9; the goal is to better define what portions of the M113 should have evolutionary technical data developed and integrated into the future acquisition plan. A digital thread enables data sharing across industrial operations and sustainment operations at the tactical and operational levels. The ideal scenario, he continued, would be to have a new piece of equipment that comes with technical data, and those data are developed into a digital thread that is stored in an

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8 “Digital thread” is defined as “the use of digital tools and representations for design, evaluation, and life cycle management.” The term digital thread was first used in the Global Horizons 2013 report by the USAF Global Science and Technology Vision Task Force

9 A “digital twin” is a virtual representation that serves as the real-time digital counterpart of a physical object or process. Though the concept originated earlier (attributed to Michael Grieves, then of the University of Michigan, in 2002) the first practical definition of digital twin originated from NASA in an attempt to improve physical model simulation of spacecraft in 2010.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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accessible central repository, making it possible to produce parts and afford repair. The digital twin of the M113 is a foundational experiment to collect data, analyze them against demand history for M113 parts, and better understand packages within a combat system for which technical data are needed from the acquisition of the first piece of equipment. Kurfess acknowledged that the digital thread enables rapid movement of new technologies into operations.

PANEL 1: MULTIFUNCTIONAL MATERIALS DESIGN

Charles Kuehmann, Vice President of Materials Engineering, Tesla/SpaceX

Kuehmann explained that despite the existence of an advanced design toolbox to develop multifunctional materials, a question remains about which materials to design, with consideration for the following hierarchy: (1) the materials genome, the building blocks of physics and the fundamental principles that define materials; (2) computational materials design, by which it is possible to gain computational control over materials and to develop feature-specific or application-specific materials to advance systems; and (3) integrated computational materials engineering, which integrates the previous techniques with computer-aided engineering and process simulation tools to design location-specific properties or for further optimization of material properties for specific applications. He described the following ideal scenario for design: the best part is no part, and the best process is no process, which reduces the cost, weight, time to buy, and engineering effort of design to zero. Tesla/SpaceX uses the following five-step process for design:

  1. What are the requirements for the design? Requirements define what a design is and does; if the requirements are wrong, the wrong item will be designed. And because requirements are typically incorrect, it is important to identify the right question at the beginning of the process.
  2. Can the part be deleted?
  3. If the part cannot be deleted, how can it be simplified to its essential features?
  4. Can the way the part is made be accelerated?
  5. Can automation be used to keep the process moving smoothly?

Kuehmann detailed the process by which aerospace systems are designed, starting with systems engineering, which develops through various system and component design efforts into an implementation in hardware and software. Next, a verification process leads to an operational system. Learning occurs throughout, and the design is reiterated, which is a time-consuming process that creates challenges in implementing fundamental solutions to problems. He noted that it is

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

critical that this V-shaped development process is compressed into a very fast combined build and test and design system to speed the pace of verification learning, iterate design, and validate at the operational level. In contrast, in the traditional V-shaped development curve there is often a need during the second verification leg of the “V” to return to the first leg and tune the system or component design. This creates multiple loops or iterations of redesign that are costly and takes away valuable time.

Processing, structure, properties, and performance comprise a manufacturing-driven paradigm, Kuehmann continued. In the design sequence, those steps are reversed, with consideration for performance at the start, followed by the development of material properties, which determine the structure, which leads to the selection of the processing step. He stressed that these steps cannot occur independently; performance and processing are part of the requirements, and it is important to determine what is needed from structures and properties to create the design. For example, because the Tesla Model 3 contained more than 400 individual parts assembled in the body line, plus a battery pack, a simplified design was needed for the Tesla Model Y. The new design includes one structure for the rear and one for the front, as well as a structural battery pack to take crash loads from the front to the rear and from side to side. This body system has only three major components, so it can be made much more quickly and efficiently from design to implementation; the Model Y also has 10 percent mass reduction, 14 percent increase in range, and more than 370 fewer parts in the body than the Model 3. A casting alloy, which could be made with high castability and enough strength for the structural aspects without allowing for heat treat or any subsequent processes, enabled this simplified design—the Model Y casting is 40 percent less expensive with 79 fewer parts. This new design also impacts the manufacturing facility, with 55 percent reduction in investment per gigawatt hour of battery pack capacity and 35 percent reduction in the floor space of the facility.

Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics, and Medical Engineering, California Institute of Technology

Greer posed a question to the audience about how they like their materials—with multifunctionality and reconfigurability or just lightweight—comparing this “materials by design” concept to the age-old, now customizable question, “How do you like your coffee?” She emphasized that processes for manufacturing strong and heavy materials as well as those for manufacturing lightweight and weak materials are well established; however, it is important to consider how to make materials that are simultaneously lightweight and mechanically resilient. To achieve this, she proposed applying the concept of architecture to materials design. For example, although the Eiffel Tower is twice as tall as the Great Pyramid of Giza, it weighs

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

three orders of magnitude less; the Eiffel Tower uses substantially less material, and both structures are still standing.

Greer described the previous decade’s research on nickel microlattices, which made clear that to achieve both lightweight and mechanical resilience, it was essential to move three more orders of magnitude down to nano-architected materials—that is, where basic building blocks of components are at the length scales where the nanosize effect contributes to the overall properties of materials. It is possible to construct a three-dimensional (3D) network out of nanoscale building blocks to induce new, unusual properties (i.e., the emergence of photonic bandgap) and combinations of properties (i.e., lightweight and mechanical strength/stiffness). The properties of these “structural metamaterials” can no longer be described fully from either the material or the structural perspectives. The size effect gives rise to unique properties on the mechanical side; for example, the “smaller is stronger” size effect indicates that common metals in their single crystalline form (e.g., nickel, copper) can become as strong as steel, owing to size reduction. When using a different technique (e.g., thin film deposition), the effect on the same metals is reversed to “smaller is weaker.” For metallic glasses that are put in tension at room temperature, smaller becomes more ductile; for ceramics, which do not typically remain intact with the application of extreme tensile stress, smaller is tougher at the nanoscale. She underscored that these varied effects only emerge at the nanoscale.

The next step, Greer continued, is to harness these beneficial size effects and proliferate them onto larger scales. For example, inherently brittle materials such as alumina, glassy carbon, and other ceramics, when sculpted even into complex 3D shapes with nano- and micro-sized thicknesses and dimensions, are able to deform and fully recover their shape after being deformed under complex stress states, without permanent damage. It is possible to build different relative densities and designs to induce different deformation trajectories into materials, reinforcing that size effect manifests itself significantly (see Meza et al., 2014, 2015; Portela et al., 2020). Hollow nanolattices enable venturing into the material property space of light weight and resilience. The approach of combined architecture with the emergence of nano- and micro-size effect in materials presents the opportunity to create new material classes through additive manufacturing. Nano-architected materials also offer the novel capability of impact resilience (see Portela et al., 2021). For example, when carbon nanolattices are subjected to impact, whatever is underneath is protected. This technique is also amenable to custom resin synthesis.

Greer outlined several other applications, including the use of additive manufacturing for nano-photonics; vat polymerization for a hydrogel infusion additive manufacturing process to swell in metal ions from their salts and convert printed metal oxides to metals; biomolecular surface functionalization to target agents for chemotherapy; the use of machine learning processes to create bio-scaffold design

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

to mimic a biological or engineered feature and to predict anisotropic stiffness; and the creation of safer and lighter lithium-ion batteries via the use of architected electrodes. She stressed the importance of scaling-up the production and fabrication of nano-architected materials, as several opportunities and properties have not yet been leveraged in the commercial world. The creative use of (1) architecture, (2) nanomaterials, and (3) atomic arrangements as “tuning knobs” in material design enables the creation of new material classes, with decoupled properties that have always been linked before, and offers extremely lightweight options.

Wei Chen, Wilson-Cook Professor in Engineering Design, Northwestern University

Chen remarked that multifunctional materials represent the future, owing to their superior performance. Most existing systems are designed by trial and error or are based on engineers’ intuition; instead, it is important to develop efficient and intelligent computational design methods to automate the design process of these heterogeneous materials.

Chen highlighted research under way in Northwestern’s IDEAL Lab. One project focuses on multifunctional materials design with a data-centric framework, which combines data from computer simulations and experiments (see Iyer et al., 2020). An example is the design of multifunctional dielectric materials, which have a wide range of applications including power lines to carry electricity. Multifunctionality is cast as a multicriteria optimization problem (e.g., storage, insulation, endurance), and the design scope covers the qualitative design decisions (e.g., what polymer to use, what surface treatment to use) and the quantitative representation (e.g., machine learning to extract descriptors around complex morphology). Computer simulation and machine learning are used to build a model to predict each property, and experimental data are used to calibrate and validate this model. Another project studies data-driven design of heterogeneous material systems (see Wang et al., 2021). Data are used to model inputs such as material type and architecture, and a novel machine learning technique allows mixed variables (i.e., quantitative and qualitative) to build a continuous Gaussian process model that can be integrated into upper-scale topology optimization. This approach makes it possible to create multiscale topology optimization–designed heterogeneous systems using a computation demand similar to single-scale topology optimization because the material law is surrogated by machine learning, and using two different materials with different architectures increases displacement by 167 percent in a compliant mechanism example.

Chen described several challenges in the computational design of multifunctional systems, including the “curse of dimensionality,” which could be addressed with methods that can search the entire design space (i.e., material,

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

architecture, and manufacturing process). Another challenge is the barrier to applying design methods caused by nonlinear behavior (e.g., accuracy and cost trade-off, lack of analytical gradient for optimization). Furthermore, multistable systems have nondifferentiable behavior, which makes automated design optimization methods problematic. Lastly, most multifunctional systems are also multiphysics systems, which creates challenges in analysis and optimization. She noted that future directions and moonshot ideas from the research perspective, in which the materials, mechanics, manufacturing, and design communities would work together, include predicting the process-structure-property-performance-function relationship across multiple scales with uncertainty quantification; using supercomputing and artificial intelligence (AI) techniques for fast 3D design integration and exploration; creating a multiscale design framework for heterogeneous systems to exploit hybrid manufacturing capability; and integrating manufacturing process impact into topology optimization.

LaShanda Korley, Distinguished Professor, Departments of Materials Science and Engineering and Chemical and Biomolecular Engineering, University of Delaware

Korley discussed the convergence of molecular design, assembly, and manufacturing through a bio-inspired lens, with particular emphasis on how molecular design of functional materials enables strategic property development. She described spider silk as one of the most “elegant” examples of convergent manufacturing in nature. The diversity of the mechanical function achieved in spider silk is due to slight modifications in its peptide sequence, which lead to variations in the hierarchical assembly, all of which are facilitated by what occurs in its “manufacturing vehicle” (the spinneret). The toughness of the material is driven by the interplay of the chemical diversity (with glycine and alanine) and chain interactions (hydrogen bonding, which leads to self-assembled structures) provided on-demand by the spider. She pointed out that different spiders have different mechanical properties and structural pieces that create different materials—for example, brown recluse spiders have flat ribbons instead of cylindrical filaments, which gives rise to more adhesive material properties. The spider demonstrates that it is possible to use molecular design to challenge the probing of interfacial interactions and to increase energy efficiency (see Chan et al., 2020; Gosline et al., 1999).

In an effort to expand the tool set for advanced manufacturing, Korley’s research group is working on the control of hierarchy in systems—design pathways include taking block copolymers that can segregate on their own into a variety of structures, generating elastomeric species, and using cross-linking. It is possible to use the overlay of covalent and dynamic interactions in these systems to explore how both secondary structure and organizational features give rise to unique properties. By tuning

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

(whether there are small bits of peptitic ordering in the system or there is a change in the secondary structure by shifting from beta sheet ordering to alpha helix ordering), it is possible to manipulate hierarchy using the interplay of different design pathways coupled with manufacturing strategies. Comparing the secondary structure of these materials systems, which can be modulated by the solvent in which the materials are formed, it is possible to make a bi-layer material that can form a helical structure when exposed to a specific environmental condition (e.g., through water). Nature provides a variety of ways to merge manufacturing pathways and molecular design—for example, pinecones have layered material property and complex materials design at the interface, which allows opening and closing in response to humidity. She highlighted a “forest of opportunities” to use templates to drive organization, with the ability to create on-demand, responsive types of systems, using environmental conditions to tailor properties. Focusing on the modularity of building blocks could enhance efficiency, she continued, and using different pathways could customize material properties for a holistic convergent manufacturing approach.

Question and Answer Session

Moderator Christina Baker, Director of Additive Manufacturing, PPG Industries, asked how students could best prepare for future work in convergent manufacturing as well as what critical research gaps remain to achieve multifunctional convergent hybrid manufacturing. Kuehmann emphasized that to push back against design requirements, one would need a broad understanding of how systems work; therefore, students should seek fundamental knowledge in a broad range of systems (i.e., materials students would take mechanical design classes). Chen acknowledged the value of developing a systems view but noted that this may be difficult to achieve in the classroom. She championed project-based learning; for example, Northwestern University offers an interdisciplinary doctoral cluster program. Korley mentioned several opportunities for students to explore beyond their discipline-specific boundaries—for example, university interdisciplinary programs, the National Science Foundation’s Research Experiences for Undergraduates, and other internships. She stressed that convergent manufacturing is about establishing a common language and set of tools to communicate in a way that moves the field forward and makes it possible to experience different aspects of the manufacturing chain.

Baker wondered about other challenges for multifunctional materials design. Chen affirmed that developing a common language with shared terminology is key to enabling communication across disciplines. Kuehmann added that in terms of multifunctionality, system design is reflective of an institution’s organizing principles; for example, product interfaces often represent institutional interfaces that create inherent boundaries. However, the goal for multifunctional materials

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

design is to erase these interfaces and improve product performance. Korley said that each aspect of the manufacturing process is often viewed as a discrete unit, with the product design the last to be considered. Instead, it is important to integrate product design early in the process: thinking from a systems perspective and including different types of materials leads to progress.

Baker asked the panelists about the potential for integrating natural resources into convergent manufacturing. Korley advocated for taking advantage of advances in catalytic technology and new synthesizing schemes that start with natural materials to create specific building blocks, which could be added to the existing value chain as building blocks for new materials that capture many of the properties and add functionality and sustainability. Baker also inquired about the potential for integrating nanoscale additive manufacturing into larger-scale additive manufacturing, and Greer described this integration of nanoscale additive manufacturing as a real challenge. Greer went on to also state that additive-manufactured materials are not well understood in terms of the properties they could enable and how they should be inspected. Thus, according to Greer, the most important aspects missing from additive manufacturing are in situ diagnostics (i.e., the ability to diagnose whether the part being produced will have the desired quality, and the ability to make those decisions in real time) and more data for machine learning. Although it is very expensive to evaluate different length scales from the nano scale and up, she continued, it is imperative to do so during the research stage—in situ diagnostic capabilities are invaluable.

Baker asked how economic decisions converge with the timing of product launches and performance expectations in the corporate decision-making process, especially in light of divergent safety considerations and cost expectations. Kuehmann noted that SpaceX and Tesla derive high-level metrics by which to measure trade-offs for engineering and manufacturing decisions. For example, Tesla is considering how quickly to replace the existing carbon-producing internal combustion engine vehicle fleet, which is an optimization problem of accelerating sustainable energy.

Baker posed a question about key challenges regarding scalability and integration—for instance, although many innovative early-stage technologies exist, it remains to be seen how they will transition into the real world. Chen explained that while data are part of the solution to the scalability problem, they are also part of the challenge, owing to the difficulty in identifying the most useful and high-quality data for which machine learning, dimension reduction, and other technologies can be applied. She portrayed design synthesis as a multiscale problem with the potential to develop algorithms that could break barriers and enable scaling. Kuehmann added that concurrent design and integration enable quicker delivery than sequential activities and reduce overall program risk. Malshe asked about the balance of top-down (system level) and bottom-up (engineering level) approaches

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×

for scalability. Kuehmann responded that Tesla/SpaceX maintains systems thinking throughout any engineering activity; when systems-level thinking permeates, an opportunity for true integration emerges.

Baker invited panelists to share additional moonshots for multifunctional materials capabilities. Greer suggested developing a model that captures complexity and physics with economically feasible computational resources. A true moonshot is the ability to enter a desired strength and weight ratio into a kiosk that would provide options on-demand for materials, including costs and properties. Kuehmann remarked that it would be beneficial to have an integration system that generates a representation of system-level performance and manufacturing to simplify trade-offs.

PANEL 2: HETEROGENEOUS MATERIALS DESIGN

Carolyn Duran, Vice President, Data Center and AI Group, Intel Corporation

Duran explained that many of the challenges for devices made by heterogeneous materials and design are similar to those that relate to the desire to shrink device sizes in accordance with Moore’s Law with the goal to create more purpose-built products that optimize for use cases and allow for restructuring, reframing, recycling, and reusing materials. She shared the following three perspectives on convergent manufacturing and heterogeneous materials interfaces: (1) At the microscale level (e.g., semiconductor manufacturing), scaling leads to interfaces dominating the materials properties; it is important to eliminate unnecessary interfaces from the scaling to reduce the number of defects, provide the best properties, and improve product performance. It is vital to consider how to achieve that with disparate materials via in situ processing. (2) At the mid-scale level (e.g., hybrid bonding of units from different manufacturers), miniaturization is enabled, device performance improves, and the hybrid bonding allows disparate silicon types to be integrated. (3) At the macroscale level, it is critical to adapt products that are already in the field via repurposing or repairing.

Abhir Adhate, Product Director, Modeling & Simulations, Sentient Science

Adhate emphasized the value of rapid and accurate material microstructural tools for heterogeneous materials development and design. Additive manufacturing techniques allow for the embedding of heterogeneous materials in components in new and interesting ways. It is important to understand the evolution of microstructure in order to understand part performance, he continued, especially in terms of part quality (i.e., how microstructure evolves after different manufacturing operations). The ability to virtually test components with heterogeneous

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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materials will thus be key to lowering costs and understanding part function. For example, cloud computing lowers barriers to entry for essential high-performance computing, especially for smaller organizations. To develop microstructure models, he indicated that an understanding of machine materials is needed via access to machine application programming interfaces (APIs) as well as material and machine data. Convergent platforms rely on models as part of quality assurance, and he stressed that understanding the intended microstructure at the interfaces of heterogeneous materials is critical for quality assurance. To achieve agile, versatile, and resilient manufacturing capabilities at the point of need, convergent manufacturing platforms would need in situ monitoring and defect correction capabilities, which require the ability to quickly develop material models, share material models seamlessly, and maintain open access to machine APIs.

Vinayak Dravid, Abraham Harris Professor of Materials Science and Engineering, Northwestern University

Dravid described energy, sustainability (of both material and financial resources), and the environment as non-colinear points that merge to create a stable plane for growth and societal progress. Therefore, when trying to advance a technology, it is critical to balance and articulate a tangible value proposition for all three segments. He championed nanoscale approaches to gigaton challenges, for example by leveraging convergent manufacturing for environmental remediation. Any science or technology that addresses gigaton challenges has to satisfy a series of convergence issues, with consideration for efficiency, effectiveness, the economy, eco-friendliness, and engineering and ergonomic compatibility. Highlighting the value of environmental remediation, he detailed the use of OHM (oleophilic, hydrophobic, and multifunctional) technology to leverage discarded waste sponges for use as substrates to create functional materials with only the addition of a coating (see Figure 2.1). When that technology is exposed to air, water, and soil as a way to attract pollutants, the pollutants are captured for reuse. This reusability cycle, in which the pollutant is removed, recovered, reused, repurposed, and recycled into a new product, could be expanded; he emphasized the importance of a life cycle analysis of a technology from birth to burial.

Kimani Toussaint, Professor and Senior Associate Dean, School of Engineering, Brown University

Toussaint highlighted the benefits of leveraging convergence to democratize biomanufacturing. He asserted that biology thrives on heterogeneity, which exists in composition and structure spanning multiple hierarchical (spatial) scales to introduce a variety of functionalities. It is critical to understand the structure

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Image
FIGURE 2.1 OHM (oleophilic, hydrophobic, and multifunctional) technology—using “waste” to “clean” waste. SOURCE: Vinayak Dravid, Northwestern University, presentation to the workshop, November 15, 2021.

function relationship, especially to replicate systems. For example, it is possible to perturb the molecular constituents of a collagen molecule—by removing the amino acid that affects the flexibility of the molecule, or modifying the amino acid sequence, in which case the system could lead to brittle bone disease. Interfaces in biological systems are especially important for replication. Complex biological systems have structural variation dependent upon the location (e.g., collagen fibers organize themselves very differently in the lungs than in the liver) or the severity of disease, as well as variation in composition in terms of functionalities.

Toussaint described a cross-disciplinary collaboration to capture a small slice of lung tissue, create a digital copy, replicate it, and feed it into a design and modeling process, which is informed by a materials database (see Figure 2.2). The initial product created via two-photon lithography undergoes advanced metrology and biological validation before machine learning is applied to compare the new product to the original system. Data obtained from this smart manufacturing platform could be uploaded to a data repository, leading to the democratization of the biomanufacturing process in which a variety of researchers and institutions could participate in the overall enterprise.

In closing, Toussaint shared knowledge gaps and technological needs for the future: (1) small footprint, ultrafast lasers with dynamic wavefront shaping capabilities; (2) multiscale and multiphysics modeling for complex, heterogeneous biomaterials; and (3) new biomaterials, and biocompatible and water soluble photoinitiators.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Image
FIGURE 2.2 Framework for manufacturing heterogeneous biomaterials. SOURCES: Kimani Toussaint, Brown University, presentation to the workshop, November 15, 2021. Image in lower right corner from W. Lee, A. Ostadi Moghaddam, S. Shen, H. Phillips, B.L. McFarlin, A.J. Wagoner Johnson, and K.C. Toussaint, 2021, An optomechanogram for assessment of the structural and mechanical properties of tissues, Scientific Reports 11(1):324, https://doi.org/10.1038/s41598-020-79602-6, Copyright © 2021 The Authors, licensed under a Creative Commons Attribution 4.0 International License.

Question and Answer Session

Moderator Jian Cao, Cardiss Collins Professor and Founding Director of the Northwestern Initiative for Manufacturing Science and Innovation, Northwestern University, observed “point of need” as a common thread among all the panelists’ presentations in this workshop, particularly in relation to repurposing, detection and repair, surface interaction, democratization of biomanufacturing processes, and supply chain agility. She asked about the barriers at the point of need as well as the system-level implementation of technology needed to overcome them. Duran replied that predictive understanding would help to anticipate and avoid failure so as to provide uninterrupted service and reduce the need for reactive repairs. Predictive understanding could be realized through a study of telemetry, diagnostics, and predictive behavior as well as modeling to optimize and reveal trends prior to failure. Adhate said that although AI and machine learning techniques are emerging to address this issue, physics is needed to understand how materials interact in different environments and under different modes of operation. Duran added that when a company does not service the end user, it is challenging to make predictions without knowing how a product may be used in the field.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Cao invited panelists to discuss additional knowledge gaps for convergence at the heterogeneous interface. Dravid remarked that there is a gap between laboratory excellence and field deployment, where the scale is much larger, particularly for issues related to energy and the environment. If it is not possible to demonstrate a proof of concept at an intermediate scale, it is difficult to make a case for it downstream. Adhate acknowledged this “valley of death” in technology development when attempting to scale concepts from the laboratory. Duran added that it is difficult, even in industry, to secure expensive pieces of equipment for testing at an intermediate scale, and Dravid observed that this issue is complicated by the fact that large companies tend to be risk averse. Toussaint commented that from an experimentalist’s perspective, data are paramount. Efforts to build smart platforms for better decision making are under way, but there has been less effort to create databases that capture work from the discovery process. He proposed that data collected during field experiments be placed in a repository and shared in an open-source intelligent manufacturing system as a way to leverage and converge the findings of different experts. He requested more attention toward the discovery process, as well as incentives to share data. Cao supported the sharing of knowledge accumulated in laboratories and on manufacturing floors instead of continuing to publish only the “good data.” Adhate highlighted the benefit of a common ontology to enable this level of data discovery and sharing. Cao wondered why a common ontology has not yet been established, and Adhate pointed out that with so many experts in niche areas, it is difficult for people to agree on terminology. Duran posited that it is difficult to develop systems-level perspectives without an integrator to connect siloes of expertise. Cao posed a question about how industry’s hesitancy to share materials data could inhibit progress. Dravid suggested an intermediate approach that would include the sharing of some data that are separated from more confidential in-house innovation data, and Adhate championed Toussaint’s suggestion of developing a database with varied levels of sharing and access.

Cao inquired as to whether convergent manufacturing could be leveraged to minimize the use of dangerous or scarce materials. Duran suggested borrowing materials for use cases and returning them for reuse. This approach would offer the benefits of modularity without the detriments of additional interfaces—it minimizes the total consumption of dangerous or scarce materials by recovering them for safe reuse. Cao wondered what manufacturing methods could be used to design material with a heterogeneous interface to enable easy separation for later reuse. Dravid responded that affordability and impact are critical; the economics and social implications of material have to be considered, as environmental laws vary by country. Duran noted that building systems with flexibility often increases complexity and cost, but a balance between simplicity and flexibility is important. Toussaint explained that specific applications for and specific aspects of material properties determine how information is distributed. For example, a substitute

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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material could be used to copy the overall structure of a malignant tissue and digitize the information for distribution. There is no one-size-fits-all solution, which reinforces the value of a well-analyzed database to make smarter decisions about how to better use materials. Dravid added that distributed solutions depend on local scenarios; instead of seeking perfection, the goal should be to develop solutions that are “good enough,” and Adhate remarked that this decision relates to the appropriateness of the requirements. Cao asked the panelists how Scope 3 relates to borrowing materials and carbon dioxide (CO2) emissions. Duran said that it is important for industries to take Scope 3 emissions into account to move closer to full life cycle analyses and circular economies, but she cautioned against unintended consequences, such as the recapture of borrowed materials increasing cost. Dravid highlighted not only the cost of purchase but also the cost of ownership; CO2 is only one of many impacts that should be considered. Adhate suggested developing interchangeable models and building metamodels of a particular product to identify the CO2 emissions from a life cycle.

Cao posed a question about affordable materials that could provide significant advantages over current aerospace materials, and Dravid replied that it is possible to develop a more affordable substrate and a surface-based solution. Toussaint noted that it is important to consider the scope of metamaterials and the issue of functionality (e.g., it is possible to print a substitute tissue that does not look like the heart but functions like the heart), which is another area in which a common language developed by experts from various fields would be beneficial. Cao presented a related question about the potential for functional metrology. Adhate responded that evaluating part performance in terms of what is allowable instead of what is safe is a very different way for engineers to think about design, and Dravid pointed out the benefits of designing holistically around the core technology.

Cao questioned how to expand convergent manufacturing. Adhate suggested open machine APIs and a common language between them to enable convergence. Dravid stressed the need for better workforce development to address gaps in manufacturing, with a value chain of talent at both the college and community college levels. Duran pointed out that because people generally fear change, it is important to demystify the notion of convergent manufacturing. Toussaint commented that as new disciplines emerge, more crosstalk would be beneficial. He proposed that postsecondary institutions update their paradigm for education to a “convergent education model” that emphasizes a common lexicon, teamwork, and problem-solving across traditional disciplinary boundaries. Dravid encouraged the professional societies to offer cross-training (e.g., bootcamps), and Toussaint emphasized the need for incentives to shift the university approach to evaluation to place value on cross-disciplinary training.

Cao observed that an objective of the Materials Genome Initiative is more rapid materials development, and she inquired about industry’s progress. Duran

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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described the goal to reach a point in which models are trusted enough to eliminate some of the test cases. New capabilities have begun to enable this progress, but she asserted that more work in experimentation and production would be beneficial, and predictive modeling is critical. Cao wondered about the availability of appropriate design software for convergent manufacturing. Adhate highlighted sectors of academia that are experimenting with design software that incorporates heterogeneity, density, and energy materials, although this software is not widely available to engineers. He added that most computer-aided design software only assumes uniform material properties—a gap that should be addressed.

Cao asked about the challenges of processing multiple materials within a single system, and Dravid used electron microscopy as an example and discussed the dichotomy between hard (e.g., metals) and soft (e.g., polymer) interfaces while examining the interface. He noted that although soft interfaces are dominated by more damage by the electron beam, it is important to find a common denominator between the two materials to extract information about the material interface such as using adaptive sampling for the soft material as not to damage it. Cao wondered if there are parallels between previous approaches to semiconductor manufacturing and current approaches to convergent manufacturing. Duran explained that the semiconductor industry solves for defects to eliminate interfaces and obtains a bulk material property at a small volume that is not dominated by surface effects. Although that is not the process that would be used in convergent manufacturing, if the objective is modularity, one could quickly treat the interface and use it in its intended state—a similar approach despite the difference in problem statements. Dravid pointed out that the semiconductor industry has been dominated by flaw intolerance, but the new paradigm for convergent manufacturing emphasizes adapting flaws and finding ways to circumvent them. Cao asked if there are bio-inspired processes most suitable for convergent manufacturing, and Toussaint referred to areas of biomimetics that have been adapted—for example, functionalizing surfaces through patterning for self-cleaning materials.

GROUP QUESTION AND ANSWER SESSION: SCIENCE, ENGINEERING, AND APPLICATION GAPS

\Moderator Sandra DeVincent Wolf, Senior Director of Research Partnerships, Carnegie Mellon University, explained that in a systems-engineering approach for manufacturing at the point of need, materials, processes, and performance requirements are evaluated simultaneously, along with the consideration for the production or repair of something at or near the point of need. In addition to the previously mentioned scalability challenges (e.g., data collection, a usable database, characterization and inspection, evaluation at length scales, in situ diagnostics), she wondered about other gaps as well as how to best invest in research and

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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development. Dravid reiterated the need to consider the technology’s impacts on the environment and the local society during the design stage. Duran remarked that more systems-level thinking would balance siloed expertise. To achieve this, the future workforce would be trained to think differently and be rewarded accordingly. Korley and Adhate restated their support for the generation of a common language that encourages communication across the full system to facilitate convergent manufacturing. Kurfess highlighted the opportunity to develop augmented intelligence tools for “human cognitive offloading”—that is, the human focuses on creativity and innovation, while the tools complete more mundane tasks. Toussaint noted that as manufacturing matures, it will be important to think about design in terms of meeting the end user’s needs (i.e., bespoke versus mass manufacturing). He cautioned that rigid definitions for concepts such as “scalability,” for example, could constrain one’s ability to rethink the framework for manufacturing.

Wolf invited the panelists to discuss gaps specifically related to design software. Adhate replied that for any design or simulation software to be useful, it should calibrate directly to data. Kurfess noted that interesting concepts are emerging around relatively inexpensive cloud-based computing capabilities: clouds can operate on Chromebooks, which increases access, especially for middle and high school students. Adhate explained that Sentient Science relies on software-as-a-service and runs on Amazon Web Services, the costs for which are steadily decreasing. As these tools become more affordable and students are able to use them, he continued, better training would be worthwhile.

Wolf observed the collective desire for a usable, curated materials database. While initiatives are under way, many challenges remain to enable data sharing. Assuming that a database with significant cybersecurity and sufficient knowledge of how to format data to be searchable and usable could be developed, she asked whether organizations would trust that database enough to contribute to it. Adhate responded that it would depend on how the organization could extract value from the material data. Toussaint pointed out that there are ways to limit the amount of (or anonymize) data in the database. A key motivator is whether people who contribute data receive something in return, such as access to other data. Duran described the Semiconductor Research Corporation, which provides a precompetitive space where people actively share fundamental research. Challenges arise in other situations when there is a specific application to a product, as industry tends only to publish things that are not working.

Wolf posed a question about the roles of the digital twin and digitization in supporting the evolution of manufacturing capabilities. Adhate remarked that the digital twin is most useful when good telemetry from the field can support sustainment. Progress is still needed to connect the digital twin to customer requirements, material selection, and material foundries. Dravid outlined the challenge of the

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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digital divide when designing technology, as not everyone has access to digital information.

Wolf asked about other research opportunities to advance both materials and the study of materials design, and Korley highlighted an opportunity to integrate product design earlier in the materials design process. Duran said that because unintended consequences and trade-offs are often not well understood, better modeling, clearer assumptions, and a better understanding of key metrics are important as well as flexibility to balance trade-offs to develop the right material. Kurfess noted that complexity expands significantly with trade-offs; although AI offers some solutions, the human will always play an important role in optimization. He mentioned the culture shift required to realize a significant opportunity for workforce development and tool development—not just for high-level engineers but also for users on the manufacturing floor. Malshe described this as the true democratization of manufacturing.

Wolf questioned how to achieve the full potential of hybrid and multifunctional materials for convergent manufacturing. Dravid expressed his desire for accelerated testing (i.e., how the material behaves) and for increased attention to the local supply chain when developing solutions (e.g., adaptive sampling and adaptive supply chain). Korley advocated for taking advantage of natural materials in different locales to facilitate access, decrease costs, and enable functionality. Adhate emphasized that undergraduate and graduate programs should prepare engineers with the right design mentality10 to effectively exploit heterogeneous and multifunctional materials. Toussaint commented that data have to be extracted at multiple scales in a variety of environments and then fused, and he suggested rediscovering the types of metrics and measures needed at these various scales and the types of metrology platforms required to extract these data. Dravid added that the life cycle analysis, including the impacts of the technology, have to be explicit from the design stage.

DAY 1 SUMMARY

Malshe provided an overview of key themes from the first day of the workshop series, noting that

  1. Convergence is motivated by the aspiration to manufacture parts that are both simple and powerful.
  2. Convergence by hybridization, hierarchy, and heterogeneity is critical, as is the transition to accepting greater risk of challenging ourselves to work with the added complexity and opportunity heterogeneity gives.

___________________

10 An openness to the possibilities available using the more complex behavior in heterogeneous materials as compared to homogeneous materials.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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  1. That progressing beyond the boundaries of Industry 4.0 requires extensive community involvement to distribute information at the point of need and to make manufacturing equitable (i.e., accessible to all), which is key to the nation’s economic well-being and security.

REFERENCES

Allouis, E., R. Blake, S. Gunes-Lasnet, T. Jorden, B. Maddison, H. Schroeven-Deceuninck, M. Stuttard, P. Truss, K. Ward, R. Ward, and M. Woods. 2013. A Facility for the Verification and Validation of Robotics and Autonomy for Planetary Exploration. http://robotics.estec.esa.int/ASTRA/Astra2013/Papers/Allouis_2824264.pdf.

Bapat, S., M.P. Sealy, K.P. Rajurkar, T. Houle, K. Sablon, and A.P. Malshe. Forthcoming. Understanding hybrid manufacturing to meet the demands of COVID-19 pandemic and beyond: Efficiency, resilience, and convergence. Smart and Sustainable Manufacturing Systems.

Chan, N.J.-A., D. Gu, S. Tan, Q. Fu, T.G. Pattison, A.J. O’Connor, and G.G. Qiao. 2020. Spider-silk inspired polymeric networks by harnessing the mechanical potential of -sheets through network guided assembly. Nature Communications 11:1630.

Gosline, J.M., P.A. Guerette, C.S. Ortlepp, and K.N. Savage. 1999. The mechanical design of spider silks: From fibroin sequence to mechanical function. Journal of Experimental Biology 202(23):3295-3303.

Iyer, A., Y. Zhang, A. Prasad, P. Gupta, S. Tao, Y. Wang, P. Prabhune, L. Schadler, L.C. Brinson, and W. Chen. 2020. Data centric nanocomposites design via mixed-variable Bayesian optimization. Molecular Systems Design & Engineering 5(8):1376-1390.

Lee, W., A. Ostadi Moghaddam, S. Shen, H. Phillips, B.L. McFarlin, A.J. Wagoner Johnson, and K.C. Toussaint. 2021. An optomechanogram for assessment of the structural and mechanical properties of tissues. Scientific Reports 11(1):324. https://doi.org/10.1038/s41598-020-79602-6.

Malshe, A., S. Bapat, K. Rajurkar, and S. Melkote. 2021. Biological strategies from natural structures for resilience in manufacturing. CIRP Journal of Manufacturing Science and Technology 34:146-156.

Meza, L.R., S. Das, and J.R. Greer. 2014. Strong, lightweight, and recoverable three-dimensional ceramic nanolattices. Science 345(6202):1322-1326.

Meza, L.R., A.J. Zelhofer, N. Clarke, A.J. Mateos, D.M. Kochmann, and J.R. Greer. 2015. Resilient 3D hierarchical architected metamaterials. Proceedings of the National Academy of Sciences 112(37):11502-11507.

NASEM (National Academies of Sciences, Engineering, and Medicine). 2019. Fostering the Culture of Convergence in Research: Proceedings of a Workshop. Washington, DC: The National Academies Press. https://doi.org/10.17226/25271.

Portela, C.M., A. Vidyasagar, S. Krodel, T. Weissenbach, D.W. Yee, J.R. Greer, and D.M. Kochmann. 2020. Extreme mechanical resilience of self-assembled nanolabyrinthine materials. Proceedings of the National Academy of Sciences 117(11):5686-5693.

Portela, C.M., B.W. Edwards, D. Veysset, Y. Sun, K.A. Nelson, D.M. Kochmann, and J.R. Greer. 2021. Supersonic impact resilience of nanoarchitected carbon. Nature Materials 20:1491-1497. https://doi.org/10.1038/s41563-021-01033-z.

Wang, L., S. Tao. P. Zhu, and W. Chen. 2021. Data-driven topology optimization with multiclass microstructures using latent variable Gaussian process. ASME Journal of Mechanical Design 143(3):031708.

Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
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Page 23
Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×
Page 24
Suggested Citation:"2 Resilient Design and Multifunctional Materials." National Academies of Sciences, Engineering, and Medicine. 2022. Convergent Manufacturing: A Future of Additive, Subtractive, and Transformative Manufacturing: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26524.
×
Page 25
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A convergent manufacturing platform is defined as a system that synergistically combines heterogeneous materials and processes (e.g., additive, subtractive, and transformative) in one platform. The platform is equipped with unprecedented modularity, flexibility, connectivity, reconfigurability, portability, and customization capabilities. The result is one manufacturing platform that is easily reconfigured to output new functional devices and complex components for systems. This manufacturing system also converges the integration of physical components and digital models along with sensor networks for process monitoring and production.

The National Materials and Manufacturing Board of the National Academies of Sciences, Engineering, and Medicine hosted a 3-day workshop event to explore research and development (R&D) opportunities and challenges for convergent manufacturing. Sponsored by the U.S. Department of Defense, the three workshops in the series were held virtually on November 15, 2021; November 19, 2021; and November 22, 2021. The workshop series focused on the following three overarching topics: (1) key areas for R&D investments that will enable the readiness and commercial development of convergent manufacturing; (2) application areas for convergent manufacturing, with an emphasis on future Army and related civilian applications; and (3) approaches for the design of a convergent manufacturing platform.

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