Simulation of Process Dependend Properties with MAT_254 Demonstrated for the ‚Bake-Hardening‘ of an 6xxx Aluminum Alloy

Taking into account the strain and thickness distributions of cold formed parts is well established in LS-DYNA. Additionally, *MAT_TAILORED_PROPERTIES offers the possibility to use a tabulated set of flow curves dependent on a history variable. The physical quantity represented by the chosen history variable can be defined by the user. Getting the distribution of this history variable may be a difficult task. For press-hardening simulation exclusively, LS-DYNA offers *MAT_244/248 to calculate the distribution of mechanical properties based on the distribution of metallurgical phases. The phase distribution is a result of the thermo-mechanically coupled simulation of the production process. To overcome the limitations of these two material models, *MAT_GENERALIZED_PHASECHANGE was implemented. This material has been used successfully for the simulation of press-hardening, welding and 3D-Printing. The current work presents a new field of application for *MAT_GENERALIZED_PHASECHANGE, simulating the “bake-hardening”-effect of specific aluminium alloys. The local final strength of hardenable aluminum alloys for automotive applications depends on the local pre-strain from the forming process and the local time-temperature-profile during paint bake. An initial approach to model this behavior is given. Implemented extensions to *MAT_GENERALIZED_PHASECHANGE, which enable are more precise description of the underlining mechanisms, will be shown.