ITERATIVE ESTIMATES OF INTERNAL-STRESSES IN SHORT-FIBER METAL MATRIX COMPOSITES

The average internal stresses and overall thermoelastic properties of short-fibre metal matrix composites are estimated by computer calculations using a variable constraint model (VCM) based on Eshelby's ideas. While the VCM appears to provide upper and lower bounds for the average internal stresses in continuous-fibre composites, it turns out not always to deliver bounds on the internal stresses or the overall thermal expansion coefficients in short-fibre composites. Instead the VCM can deliver self-consistent iterative estimates by a computational scheme exploiting an analytic form of Eshelby's S tensor for a transversely isotropic matrix. The iterative estimates are, for high fibre contents, preferable to the conventional lower bound estimates.