Numerical Simulation For Ratcheting Of Particle Reinforced Metal Matrix Composites Based On Periodical Boundary Condition

When the materials and structures subjected to a cyclic stressing with non-zero mean stress, a cyclic accumulation of inelastic deformation will occur in the direction of average stress, which is called ratchetting. Due to the complicated internal structure of the composites, the research of the ratchetting effect of the composites is very difficult. Domestic and international scholars had a lot of researches, and attained valuable experimental and theoretical achievements. Recently, following the rapid development of computer, finite element softwares have been used in numerical simulation for the ratchetting effect of the composites, which greatly improve the calculation efficiency and accelerate the experimental and theoretical research progress.Three-dimensional elastic-plastic finite element models were used to analyze the ratchetting behavior of SiC/6061Al composites:Firstly, the effects of stochastic properties of SiC particles on the ratchetting behavior of SiC/6061Al composites were numerically analyzed by employing a 3D multi-particulate unit cell and using an existed cyclic constitutive model. A 3D multi-particle unit cell containing randomly distributed particle was generated by Random Sequential Adsorption (RSA) method in the simulation. It is shown from the results that:results of the single numerical simulation indicated dispersion. The introduction of statistical method decreases the dispersibility of the simulation results, the reliability of results were highly increased.Secondly, the three-dimensional simulation model, which can be applied in periodic boundary conditions, had been built by used Hypermesh. The periodic boundary conditions and simplified boundary conditions were used to simulate the cyclic deformation behaviors of SiC/6061Al composites. It is shown from the results that:there is a relatively large deviation for calculating results under two kinds of boundary conditions, and the numerical results with periodic boundary conditions satisfy experimental data, showing the result is more reasonable.Thirdly, simulate the monotonic tensile and ratchetting behaviors of SiC/6O61Al composites with periodic boundary condition. The microscopic features, such as the particulate shape, numbers and size as well as the arrangement, were concerned in the numerical simulation of the ratchetting mechanical properties of the composites. It is concluded that increasing the particulate numbers and decreasing particulate size contained in the unit cell can enhance the reinforcement of the particles. The boundary of the particulate is more poignant, the reinforcement of the particles is more enhanced; increasing the stacking density of the particles can enhance the flow stress of the composites.