| In recent years,automotive lightweighting has become one of the development trends of the automotive industry.Aluminum alloy has become one of the most ideal materials in current automotive lightweighting technology because of its high specific strength,abundant reserves and recyclability.Aluminum alloy hot stamping can obtain high-quality parts.Therefore,The damage evolution and formability of 7075 aluminum alloy during hot stamping were studied based on meso-damage.The specific studies are as follows:The damage evolution of 7075 aluminum alloy during tensile deformation at different deformation temperatures was analyzed by high-temperature in-situ tensile experiments,and the stress-strain curves were obtained.Based on the experimental data,the GTN damage parameters at different temperatures were calibrated by the finite element reverse calibration method,and the obtained damage parameters were coupled to the uniaxial tensile finite element model to verify the accuracy of the damage parameters.The forming limit of 7075 aluminum alloy at different temperatures was tested by isothermal Nakazima experiment.The experiment was analyzed by a finite element model coupled with GTN damage.The thickness distributions and fracture locations of different specimens obtained from the finite element simulation were in agreement with the experimental results.It is shown that the GTN damage model is sufficient to describe the mechanical properties and fracture characteristics of 7075 aluminum alloy well.The influence of different process parameters on the stamping quality of automobile S-rail was analyzed by numerical simulation.The results show that high-quality 7075 aluminum alloy S-rail parts can be obtained by hot stamping under the conditions of stamping speed of 40mm/s,initial blank temperature of 410°C,friction coefficient of 0.1and blank holder force of 5k N.It provides some theoretical support for the hot stamping forming process of 7075 aluminum alloy.Figure 50;Table 5;Reference 62... |
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