食材

食材

結果 (英文) 1:

Ingredients

結果 (英文) 2:

The combinations of two or more different materials are called composite materials. They usually have unique mechanical and physical properties because they combine the best properties of different materials. For example, afibre-glass reinforced plastic combines the high strength of thin glassfibres with ductility and chemical resistance of plastic. Today composites are being used for structures such as bridges, boat-building etc.

Composite materials usually consist of synthetic fibers within a matrix, a material that surrounds and is tightly bound to the fibers. The most widely used type of composite material ispolymer matrix composites (PMCs). PMCs consist of fibres made of ceramic material such as carbon or glass embedded in a plastic matrix. Usually the fibers make up about 60 per cent by volume. Composites with metal matrices or ceramic matrices are calledmetal matrix composites (MMCs) andceramic matrix composites (CMCs), respectively.

Continuous-fiber composites are generally required for structural applications. The specific strength (strength-to-density ratio) and specific stiffness (elastic modulus-to-density ratio) of continuous carbon fibre PMCs, for example, can be better than metal alloys have. Composites can also have other attractive properties, such as high thermal or electrical conductivity and a low coefficient of thermal expansion.

Although composite materials have certain advantages over conventional materials, composites also have some disadvantages. For example, PMCs and other composite materials tend to be highlyanisotropic – that is, their strength, stiffness, and other engineering properties are different depending on the orientation of the composite material. For example, if a PMC is fabricated so that all the fibers are lined up parallel to one another, then the PMC will be very stiff in the direction parallel to the fibers, but not in the perpendicular direction. The designer who uses composite materials in structures subjected to multidirectional forces, must take these anisotropic properties into account. Also, forming strong connections between separate composite material components is difficult.

The advanced composites have high manufacturing costs. Fabricating composite materials is a complex process. However, new manufacturing techniques are developed. It will become possible to produce composite materials at higher volumes and at a lower cost than is now possible, accelerating the wider exploitation of these materials

結果 (英文) 3:

Ingredients