High modulus composite

Radiation damage effects are likely to be of prime importance in organic matrix composites. Screening measurements to assess the severity of the problem are needed. For most of these materials, there is no low-temperature data base. Specifications for industrial laminates (NEMA/ASTM) are generally electrical in nature, and mechanical specifications may be necessary additions for low-temperature applications. Very few 4 K data exist for the advanced (high-modulus) composites and specialty fiberglass composites, which may be needed for low-temperature structural applications near pulsed coils. 

The two types of support structures for the solar collectors and equipment that will be considered are the rigid deployable skeletal (RDS) structure and the rigidised inflatable flexible continuum (RIFC) structure both types of structure need to be lightweight and rigid and, in the case of the skeletal structure, high modulus composite materials would be used. In addition, the structures must be able to be folded to a minimum volume to be placed in the cargo bay of the Launch Vehicle, launched and deployed at LEO, and then taken to GEO by space tug,Wingo (2004). 

Similar structures for other aerospace venicles are in various stages of design, fabrication, and testing by United States firms. Lack of experience with large, high-modulus composite structures usually necessitates several iterations before development of the proper structure to meet specific flight requirements. For example. 

Thus, according to TGA and TMA data, it is possible to estimate the temperature interval, in which polyurethane isocyanurate polymers may operate without significant softening and degradation. For low-modulus polyurethane-isocyanurates, this range runs from -50 to 190°C, and for high-modulus composites it may reach 330°C. 

The most common matrix materials of carbon-fiber composites are the polymers, also called resins or plastics. Carbon-reinforced polymers are low-density, high-strength, and high-modulus composites with extensive applications, especially in aerospace as mentioned above. Their cost is still high but is gradually decreasing as the fabrication techniques are becoming less labor-intensive. 

Composite curing stresses, called residual stresses are significant and, in the case of high-modulus composites, can cause part failure on cool-down from cure. These stresses wiU also cause Poisson s ratio strains. 

Compression ASTM D-695 (modified for high-modulus composites) Celanese, ASTM D-3410 IITRI, ASTM D-3410 sandwich beam, ASTM D3410... 

In the case of bonded high modulus composites, failure at low load levels due to interply delamination within the composites is a common problem. The use of low modulus adhesives minimizes this problem. 

Vitahium FHS ahoy is a cobalt—chromium—molybdenum ahoy having a high modulus of elasticity. This ahoy is also a preferred material. When combiaed with a properly designed stem, the properties of this ahoy provide protection for the cement mantle by decreasing proximal cement stress. This ahoy also exhibits high yields and tensile strength, is corrosion resistant, and biocompatible. Composites used ia orthopedics include carbon—carbon, carbon—epoxy, hydroxyapatite, ceramics, etc. 

Reinforcements. The high modulus, high intrinsic strength, and temperature stabiHty make SiC, in the form of whiskers, platelets, and fibers, a promising candidate reinforcement material for metal, polymer, and ceramic matrix composites (qv). 

Today, carbon fibers are still mainly of interest as reinforcement in composite materials [7] where high strength and stiffness, combined with low weight, are required. For example, the world-wide consumption of carbon fibers in 1993 was 7,300 t (compared with a production capacity of 13,000 t) of which 36 % was used in aerospace applications, 43 % in sports materials, with the remaining 21 % being used in other industries. This consumption appears to have increased rapidly (at 15 % per year since the early 1980s), at about the same rate as production, accompanied by a marked decrease in fiber cost (especially for high modulus fibers). 

A high modulus gradient at the interface is also be avoided in materials Joined as a result of the interdiffusion of materials to form a fractal surface [32]. The effect is to produce an interfacial composite region. This strengthens the interface and leads to a more gradual change in modulus and avoids the sharp concentrations of stress which would occur at a smooth interface. 

For a high-modulus graphite-epoxy composite material with... 

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