Application of Lightweighting Technology to Military Aircraft, Vessels, and Vehicles (2012) / Chapter Skim
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5 Cross-cutting Issues and Challenges
5 Cross-cutting Issues and Challenges
Pages 103-127
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From page 103... ...
Although the relative importance of lightweighting and attributes differs across the spectrum of military vehicles, lightweighting of all types of vehicles is hindered by at least two common barriers. First, the time required to develop and certify new materials and process technologies generally exceeds that required for development and certification of a military vehicle.
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From page 104... ...
Here, "maturity" encompasses the establishment of an adequate, stable supply of materials as well as the manufacturing capability to produce useful forms of these materials in order to ensure that the capability exists for streamlined insertion of lightweight materials into designs. Second, the current acquisition process for military vehicles is expensive and lengthy.
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From page 105... ...
Specifically, the implementation and broader use of comprehensive materials models, as embodied by inte grated computational materials engineering (ICME) , need to be integrated with systems design and optimization 6 See,for example, NRC, Pre-Milestone A and Early-Phase Systems Engineering, pp.
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From page 106... ...
This is especially critical for lightweighting materials technology, because integration of the materials with design and configuration would be extremely important. The process could be further accelerated through greater use of advanced technology demonstration programs (see Chapter 1)
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From page 107... ...
Structural topology is an important area of research and is an integral element of the systems-level design approach discussed in this report. An example of the approach can be found in, "Materials Selection Combined with Optimal Structural Design: Concept and Some Results."10 In this article the authors link materials data from the Cambridge Material Selector (CMS)
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From page 108... ...
An example is the work at Johns Hopkins University on topology optimization, a computational method for optimizing the design of structural systems as well as the design of multifunctional materials.13 Recent work at the University of Notre Dame has investigated structural topology optimization for blast mitigation in ground vehicles. 14 These tools and techniques are being used in the private sector,15 but the technology is still a long way from being fully developed.
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From page 109... ...
This could also yield additional benefits in the out-of-plane stiffness and strength.18 5.3 INSERTION OF LIGHTWEIGHTING MATERIALS AND TECHNOLOGIES 5.3.1 Timeline for Technology Development and Insertion As discussed in Chapter 1, the time required to develop and certify materials generally exceeds that required for product development and certification. The time can range widely -- from a few years for derivative materials on an expedited schedule to a decade or longer when a new class of material is under development or where new infrastructure is required to produce the material or structure.19 The major challenge is to shorten the timeline for materials development and bring it in line with that for product development.
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From page 110... ...
This level of maturity is usually required for a technology to be included in the detailed design phase of a product or system. For major DoD systems, development and acquisitions must adhere to Defense Acquisition Management System requirements.
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From page 111... ...
Backman, 2010, "Advancement and Implementation of Integrated Computational Materials Engineering (ICME) for Aerospace Applications," a white paper sponsored by the Air Force Research Laboratory, AFRL-RX-WP-TP-2010-4151, March, available at http://www.dtic.mil/cgi-bin/GetTRDoc?
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From page 112... ...
Regardless of whether such an idealized process could be supported in practice, it is clear that accelerating the design, development, and insertion of new materials and manufacturing processes is critical to future products and systems. This is especially true for lightweighting materials technologies, which would be best selected and assessed as part of an integrated systems development process.
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From page 113... ...
Note: MRL and TRL gates align through TRL/MRL-7 Generic Product or System Development Based on Integrated Product Deployment Process - IPD Product Concept Concept Preliminary Valida on/ EIS, Design & 0 1 2 3 4 Produc on & 5 Op miza on Ini a on Design Cer fica on Ini al Support Valida on Program Process Reviews Launch Period of Highest and Gates Development Investment A B C Defense Acquisi on Milestones FIGURE 5-5 How technology readiness for materials and processes relates to product and system development. SOURCE: Adapted from B.A.
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From page 114... ...
ICME In the context of materials and process develoment, integrated computational materials engineering is the analog to systems engineering in vehicle design. For ICME, the "system" is the set of manufacturing processes, materials systems, and engineering applications.
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From page 115... ...
For example, work at Sandia National Laboratories has resulted in open-source tools for molecular modeling that has been used extensively and is continuously updated to add more fundamental physics information and to increase computational speed. Continued progress on such physics-based modeling and simulation is needed.25 Example of Modeling Challenges: Polymer Composites An example of the progress and the disconnects in current modeling abilities for materials relevant to structural lightweighting is in the area of polymer composite materials.
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From page 116... ...
Available at http://www.transportation.northwestern.edu/docs/2011/2011.04.06.BAC_Olson_Presentation.pdf. By permission from QuesTek Innovations LLC.
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2003. Strategic Environmental Research and Development Program (SERDP)
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From page 118... ...
The first key lesson learned from this project is that reliable thermodynamic databases are essential to the design of multicomponent alloys and that fidelity tests are required to increase the confidence level for the predictions in specific regions of compositions. High-confidence thermodynamic predictions not only eliminated several of the experimental iterations that are usually needed to obtain the right alloy compositions (GTD262 was designed without even a second round of experimental trials)
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From page 119... ...
GE teams have since successfully designed and deployed into GE products new superalloys at similar high speed and low cost as a result of using the same AIM/ICME approach, which has now firmly established a vital role in new alloy development at GE.
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From page 120... ...
Frankland, and T.C. Clancy, 2005, "Computational Materials: Multiscale Modeling and Simulation of Nanostructured Materials," Composites Science and Technology, Vol.
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From page 121... ...
, and the need to meet mutually agreed upon cost, schedule, and objective performance baselines such that there is a rapid transition to deployment. The recent revision to the Defense Acquisition Guide, through DOD Instruction 5000.02, actually calls for ATDs in the preacquisition phase of development -- that is, before Milestone B, in the technology development phase.
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From page 122... ...
The design solutions that look the most favorable could then progress to the ATD stage or physical prototyping stage. ATDs have brought about revolutionary military vehicles.
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From page 123... ...
A summary of the most important of these materials and their current status is provided in Table 5-3, which also includes high-strength steels, because even modest improvements in steel strength can have a large impact due to the large amounts of steel used in military vehicles. Some alloys, such as those based on aluminum, are readily available.
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From page 124... ...
Fiber structure fiber-reinforced and technologies base metal alloys reinforced Ship superstructure metal matrix composites (MMCs) Metal matrix Land vehicle structure, Limited sources for Limited sources and High compared with base composites: (b)
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From page 125... ...
Although significant weight benefits could be achieved through the use of titanium alloys in land vehicles and ships, their high cost and a somewhat limited production capability severely restrict their use in these areas. Carbon fibers have been used extensively as reinforcements in polymer matrix composites.
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From page 126... ...
The benefits are derived in part because of the large use of steels in military vehicles. However, the lack of availability of new steels and of large-scale production remains an impediment to their wider use in military vehicles and components.
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From page 127... ...
Furthermore, with the enormous magnitude of military operations and associated costs, such strategies are expected to have a broad impact on national concerns that extend beyond the military: notably, the sustainability of fossil fuel use at present levels, the balance of trade, and domestic employment opportunities.
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