Ratcheting prediction of Al 6061/SiCP composite samples under asymmetric stress cycles by means of the Ahmadzadeh-Varvani hardening rule

摘要

The present study intends to examine ratcheting response of SiCP particle-reinforced Al 6061 matrix (Al 6061/SiCP) composite samples over asymmetric load cycles based on the kinematic hardening rule of Ahmadzadeh-Varvani. The Ahmadzadeh-Varvani hardening rule offered a simple framework by taking into account of both material and stress level dependent coefficients to predict the quasi-shakedown of ratcheting of composite samples with various volume fractions under single- and multi-step loading conditions. The coefficients in the Ahmadzadeh-Varvani rule were estimated by means of mathematical expressions involving material properties, mean stress, and stress amplitude for any given stress levels. Ratcheting strain progressively increased as composite materials experienced low-high loading sequences when stress level increased over steps of loading histories. Ratcheting strain curves of low-high and high-low loading histories were successfully predicted. The predicted ratcheting curves with high-low loading sequences have shown change in ratcheting direction consistent with the experimental data.