Going to Extremes Meeting the Emerging Demand for Durable Polymer Matrix Composites (2005) / Chapter Skim
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1 Background and Overview
1 Background and Overview
Pages 4-15
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From page 4... ...
A multitude of layered, continuous-fiber-reinforced, particulate-reinforced, and nanoparticle-filled materials can be called PMCs. For the purposes of this study, composite materials consist of micron-diameter fibers bound in a polymer matrix and used for high-performance structural applications.
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and radio frequency (RF) shielding, brushes Low biological reactivity and permeability by Medical prostheses, surgery and x-ray equipment, implants, x-rays tendon/ligament repair Fatigue resistance and self-lubrication General engineering applications with moving parts, such as automobiles Low chemical reactivity, high corrosion Chemical exposure; radiation fields; valves, seals, and resistance pump components Electromagnetic properties Electronic devices; motor and generator parts; radiological equipment polymer mobility, allowing the mechanical and thermal properties of a composite to be dramatically altered even with very small volume fractions.1,2 Extreme Environments An extreme environment for a PMC can mean different things to different people and can depend strongly on their science or engineering background.
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Because marine applications are in a salty environment, consideration must be given to avoiding dissimilar material combinations, which can lead to galvanic corrosion. The use of polymer composite materials in the offshore oil industry is driven by their lighter weight and better resistance to corrosion compared to steel.
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rolled flammability cost, repairability homogenous steel (RHS) , toughness, flammability Ocean Submersible Steel or nickel -32 to 300°F Corrosion, fatigue Weight, fatigue strength, Corrosion resistance, fabrication vehicles base damage magnetic properties cost, stiffness, fatigue strength, compression, interlaminar strength Oil and gas Steel 1.5 million lb Validation of design and Reduced life-cycle costs, Tools to enable design, drilling risers, axial tension; prototype manufacturing reduced weight, corrosion validation, accurate prediction of platform tethers 3,000 psi and meeting regulatory resistance, tolerance to long-term performance, defining internal requirements fatigue, extended reach appropriate safety factors pressure Oil and gas pipes Steel Tension Validation of design and Reduce weight, avoid Tools to enable design, 250,000 lb; prototype and meeting corrosion, cost effective validation, accurate prediction of compression regulatory requirements long-term performance, defining 20,000 lb appropriate safety factors Space Satellites and Aluminum, -250 to +250°FMicrocracking, strength Improved directional Outgassing, dimensional space titanium, and >500°F (SEV)
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can break the covalent bonding; chemically bound water can be released within the composite, causing expansion and debonding, as happens in high-temperature exposure. For satellites and space exploration vehicles, weight and dimensional stability are key parameters in material selection.
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Today there are a number of adequate composite materials successfully operating in space, but there is always a need to improve directional specific properties by using materials that are stronger yet lighter. The introduction of nanoparticles into resins might offer potential in this direction.
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2003. Two-dimensional strain mapping in model fiber-polymer composites using nanotube Raman sensing.
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SOURCE: The Research Requirements of the Transport Sectors to Facilitate an Increased Usage of Composite Materials. Part I: The Composite Material Research Requirements of the Aerospace Industry.
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Redesign using PMCs and cast aluminum reduced the total to almost 15,000, leading to a 53 percent savings in both weight and in labor hours.10 FIGURE 1-4 Projections for composite use in the Boeing 787.
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Key design requirements include impact resistance, acoustic and vibration loads, and chemical compatibility with lubricants. In vehicles with speeds of Mach 3 or higher, airframes and engine ducts are typically constructed of titanium or superalloys to withstand exposure to the aerodynamic heating of components and the engine heat.
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From page 14... ...
The difference between typical structural PMCs and polycrystalline metal components such as steel I beams or superalloy turbine blades lies in the degree of anisotropy and degree of heterogeneity. In a typical composite material intended for structural applications, the heterogeneity between a polymeric matrix and a reinforcing fiber is enormous, with the ratio of Young's modulus of the two phases nearing 1,000 to 1 (with the fiber being the larger)
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Considering the past 50 years of research by the multitude of materials scientists, solid state physicists, and mechanical and materials engineers on the structure-property relationships and processing-properties relationships for metals, and the remaining unknown issues within the engineering metals field (fatigue crack initiation or stress-corrosion cracking are good examples) , it is no surprise that interdisciplinary work remains to be done on composite materials.
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