Modeling Cyclic Deformation With the MATMOD-BSSOL Unified Constitutive Equations

The capability of the MATMOD family of unified constitutive equations to simulate cyclic deformation is demonstrated. The MATMOD approach to deformation modeling is reviewed and the most recent and complete model, MATMOD-BSSOL, is presented. This model is briefly described, emphasizing the blend of physics and phenomenology used to design terms in the equations that enable them to properly simulate cyclic deformation. Computer calculations using MATMOD-BSSOL are presented to demonstrate the ability of the MATMOD family of equations to model various cyclic deformation behaviors, including: directional strain softening, cyclic hardening, softening, and saturation. The physically realistic way in which the equations produce these behaviors is discussed. Finally, MATMOD is used to predict the stresses and strains ahead of a crack tip in a material subjected to variable temperature cyclic loading. This demonstrates the usefulness of MATMOD as a tool for solving complex structural problems.