Based On The Stress State Of Metal Material Deformation Behavior Research

The properties and press states of metal materials play crucial roles intheir deformation and cracking process. The stress state parameters areintroduced, including Stress triaxialityR_σ, Lode parameterμ_σand Stress statesoft coefficient, to characterize the stress states of materials.A novel plastic deformation partitioning method, which combinesR_σwithμ_σ, was proposed and quantified in this study. This method under thevalues of Stress triaxiality and Lode parameter in the deformable bodies, thisstudy divde the plastic deformation zone into five basic types. They areelongation deformation under tensile stress(R_σ>0,μ_σ<0); Compressiondeformation under tensile stress(R_σ>0,μ_σ>0); Elongation deformation undercompressive stress(R_σ<0,μ_σ<0); Compression deformation undercompressive stress(R_σ<0,μ_σ>0); Planar deformation (μ_σ=0). Furthermore,theR_σ,μ_σand the new partitioning approach were visualized by thesecondary development of DEFORM.The variations of two stress state parameters were studied by simulatingseveral plastic deformation processes. Then combined with the new partitionapproach, the visualizations ofR_σ,μ_σand the new partitioning methodwere discovered capable of prompting the modularity of the complexdeformation process and providing convenience to analyze the changes ofthe materials stress-strain states under different applied loads. In addition,these visualizations may observe the status of destructive deformation zonesto some extent and provide the basis for analyzing and predicting thesituations of metal flow in these zones.It was possible to lead to positive tensile fracture in the areas with theR_σ>0andμ_σ<0corresponding to the elongation under tensile stress. If thestress triaxiality was larger than the threshold, the open crack would occur inthe area, and its cross section was perpendicular to the ground.