Numerical analysis and in-situ SEM observation of damage development for woven fabric composite materials

摘要

Although woven fabric composite materials have high performance, it is very difficult to reveal their mechanical behaviours due to the geometric complexity by theoretical analysis. Especially under damage development, several kinds of failure mode such as matrix cracking, fiber breaking and transverse cracking in fiber bundle affect the mechanical behaviour strongly. In order to analyze the mechanical behaviour, three-dimensional finite element analytical procedure based on damage mechanics has been developed. In this paper, the developed procedure is applied to plain woven fabric composites, and the mechanical behaviour under damage development by on-axis tensile load has been analyzed. On the other hand, on-axis tensile test has been performed in SEM and the damage development at the edge cross-section of specimen has been observed. As a result, it can be confirmed that the calculational and the experimental results have a good agreement. Then, the mechanical behaviour depends on the edge effect of free side surface. Therefore the effect of free edge has been evaluated quantitatively by numerical analysis from comparison with mechanical behaviour under periodic boundary condition without free side surface. From the above results, it is recognized that the proposed procedure is very useful for the material design of woven fabric composite materials.