Architectural design of preforms and their effects on mechanical property of high temperature composites

To study the mechanical properties of high temperature composites, three types of needle punched performs with three different punching densities were prepared and their respective carbon/carbon composites were produced. In order to determine the proper level of needle punching, process parameters and material parameters have been considered. Optimal needle punching was designed to have the most uniform interval of needle trace and the least overlaps of needle sites. Mechanical properties such as tensile strength and flexural strength showed close relationship with the needle punching density, and they showed large differences between the x (in-plane) and z (through- thickness) directions. However, compressive strength had little correlations with the needle punching density and the direction. OxiPAN fibers showed better mechanical properties than carbon fibers because they suffered less damage by needle punching, and fabrics made of filament fibers showed higher mechanical properties than those made of spun or staple fibers.