Experimental and multiscale numerical simulation of tensile strength of a randomly oriented short fiber composite in a brittle matrix

Tensile strength of gypsum matrix composites containing different volume fractions of randomly distributed short aluminum fibers with 6, 9 and 12 mm length has been modeled by using multiscale finite element analysis. In order to simulate tensile behavior of the composites, each specimen with a particular fiber volume fraction was considered as a combination of numerous cubic elements each of which contains short fibers with variable local fiber volume fraction and independent arbitrary orientations. Numerical models were conducted based on the micro-mechanical methods of Cox (combined with Halpin–Tsai approach), by applying different random distribution functions. The results have been verified by experimental data obtained from tensile tests carried out on special briquette-shaped composite specimens. The numerical analysis gives satisfactory agreement with the experimental results. By increasing bonding strength of aluminum fibers to the matrix (i.e., by anodizing) agreement between experimental and numerical results is more pronounced.