| The Structure components are often subjected to asymmetrical cyclic loading. A cyclic accumulation of inelastic deformation (i.e., ratcheting) will occur in the components when a cyclic stressing with non-zero mean stress is applied. Ratcheting effect is very important to the safety design and life assessment of engineering structures, and has been widely studied. In the last two decades, many experimental and theoretic researches on ratcheting for metallic materials have been reported. The cyclic constitutive models of ratcheting, and its finite element implementation have advanced significantly. However, the existing researches are only limited to the monolithic metallic materials, They can not be directly extended to the particulate reinforced metal matrix composite (PRMMC), which is homogeneous in macro-scale but heterogeneous in meso-scale. So, based on the existing experiments, it is of great importance to carry out a thoroughly study on the cyclic deformation behavior of the composite.In order to carry out a creative research on the cyclic deformation behavior of the particulate reinforced metal matrix composite (PRMMC), the present thesis mainly concerns with the following topics:1. The uniaxial cyclic deformation of T6-treated SiCp/6061Al alloy composites was observed by experiments at room temperature and 300℃. The cyclic softening/ hardening feature and ratcheting behavior of unreinforced matrix and the composites containing two kinds of particulate volume fractions were discussed under the different loading conditions. The effects of loading history, strain/stress rate and holding-time at peak/valley points of each cycle on the ratcheting were discussed. The results are helpful to construct a constitutive model of ratcheting for the composite.
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