THE TENSILE-STRENGTH OF SHORT-FIBER-REINFORCED COMPOSITES

Tensile strength is one of the most im porta nt mechanical properties of structural short fibre composites, and its prediction is essential for composite design. This paper develops a strength theory for three- dimensionally oriented short fibre-reinforced composites. The contribu tion of direct fibre strengthening to the composite strength is derive d using a maximum-load composite failure criterion. Other strengthenin g mechanisms, such as residual thermal stress, matrix work hardening a nd short fibre dispersion hardening are also incorporated into the cal culation of composite strength. In the derivation of direct fibre stre ngthening, the strain and stress of short fibres with different inclin ation angles were first derived, and the direct fibre strengthening wa s calculated from the maximum total load these short fibres can carry in the composite loading direction.