A cyclic visco-plastic constitutive model for time-dependent ratchetting of particle-reinforced metal matrix composites

Based on the Eshelby equivalent inclusion theory and the extended Mori–Tanaka (MT) method, a new visco-plastic meso-mechanical constitutive model was proposed to predict the time-dependent ratchetting of particle-reinforced metal matrix composites (i.e. SiCP/6061Al composites) presented under the stress-controlled cyclic loading conditions at various stress rates and with certain peak stress holds. In the proposed visco-plastic meso-mechanical model, the time-dependent constitutive equations were formulated as linear thermo-elasticity-like relations by the generalized incrementally affine linearization method. A new extension of Mori–Tanaka homogenization model was developed for the visco-plastic composites subjected to a stress-controlled cyclic loading. Moreover, a nonlinear kinematic hardening rule similar to that used in the previous work [Guo, S.J., Kang, G.Z., Zhang, J., 2011. Meso-mechanical constitutive model for ratchetting of particle-reinforced metal matrix composites. Int. J. Plast. 27, 1896–1915] was employed to describe the time-dependent ratchetting of un-reinforced metal matrix which exclusively determines the ratchetting of the composites. With assumption of spherical particles, the capability of the proposed model to predict the time-dependent ratchetting of SiCP/6061Al composites was verified by comparing the predicted results with the corresponding experiments or finite element simulations. It is shown that the proposed model predicts the time-dependent ratchetting of SiCP/6061Al composites very well.