Microscopic stresses of discontinuous carbon fiber reinforced thermoplastics under thermal loading: two-fiber interactions

Abstract

Discontinuous carbon fiber reinforced thermoplastics have a random fiber distribution, leading to complicated microscopic stresses under thermal loading. This complex condition can be simplified as an interaction between two individual fibers. The thermally induced microscopic stresses within 20 different representative volume elements were simulated in this study by leveraging a finite element modeling strategy involving the shear lag and Saint Venant's principles. It was found that the normal stress perpendicular to two short fibers at the cross point increased with the inter-fiber spacing and decreased with the orientation angle. The inter-fiber spacing and orientation angle to the residual von Mises stress at the cross point fits a newly proposed binary function. The results support the understanding of thermally induced microscopic stresses in discontinuous carbon fiber reinforced thermoplastics.