Abstract
Internal stresses in three-dimensional fabric composites are reported to be remarkably higher than those in usual laminate composites. Therefore three-dimensional fabric resin matrix composites produced by general forming method have many cracks in the matrix and along the interface between reinforcement and matrix. In this paper, the effect of mixing fillers in the matrix resin on the internal stress in the three-dimensional fabric composites was examined aiming to develop prevention method of the cracks along the interface and in the matrix. Among commercially available particulates, quarts, glassy carbon, and silicone rubber were chosen as the filler for the matrix resin. The internal normal stress on the interface was calculated from the experimentally obtained values of thermal expansion coefficient and Young's modulus of the filler-mixed resin. It was found that quartz and glassy carbon particulates were of little effects but dispersing silicone rubber particulate was quite effective to lower the internal stress in three-dimensional composites. It was also found that the silicone rubber particulates were turned into microvoids in this composite. Thus the effect of mixing silicone rubber particulates is actually equal to that of the microvoids.
