EFFECTS OF TANGENT OPERATORS ON PREDICTION ACCURACY OF MESO-MECHANICAL CONSTITUTIVE MODEL OF ELASTO-PLASTIC COMPOSITES

Abstract

With a newly developed homogenization cyclic constitutive model of particle reinforced metal matrix composites [Guo et al. (2011)], the effects of tangent operators, i.e., continuum and algorithmic tangent operators [defined by Doghri and Ouaar (2003)] on the accuracy of the developed meso-mechanical constitutive model to predict the monotonic tensile and uniaxial ratchetting deformations of SiC P /6061 Al composites were investigated in this work. The predictions were obtained by the developed model with the choices of different tangent operators and various magnitudes of load increments. Comparison of prediction accuracy and necessary error analysis on the results obtained by different tangent operators were conducted. It is shown that: the stress or strain difference in each load increment and produced by using different tangent operators will accumulate step by step; accurate prediction should be obtained by employing a load increment small enough, especially when the algorithmic tangent operator is used in predicting the uniaxial ratchetting of the composites.