ANALYSIS OF THE STRENGTHENING MECHANISM-BASED ON STRESS-STRAIN HYSTERESIS LOOP IN SHORT-FIBER-REINFORCED METAL-MATRIX COMPOSITES

The strengthening mechanism of short fiber or whisker reinforced metal matrix composites has been studied by a continuum mechanics treatment utilizing finite element analysis (FEA). To assess. the tensile and c ompressive constitutive responses, a constraint-unconstraint comparati ve study based on stress-strain hysteresis loop has been performed. Fo r analysis procedures, the aligned axisymmetric single fiber model and the stress grouping technique have been implemented to evaluate the d omain-based field quantities. Results indicate that the development of significant triaxial stresses within the matrix both for the tensile and compressive loading, due to the constraint imposed by reinforcemen ts, provide an significant contribution to strengthening. It was also found that fiber stresses are not only sensitive to the fiber/fiber in teraction effects but also substantially contribute to the composite s trengthening both for the tensile-and compressive loading.