Effect of aging treatment on bending collapse and energy absorption of 7003 aluminum alloy bumper beams

The bending collapse and energy absorption of 7003 aluminum alloy bumper beams under four aging conditions (pre-aging, under-aging, peak-aging, and over-aging) were investigated through three-point bending tests. Microstructural characterization was performed using scanning electron microscopy and transmission electron microscopy. Based on the Swift−Hockett−Sherby constitutive model combined with the Gurson−Tvergaard−Needleman damage model, the plastic response and fracture behavior of the 7003 aluminum alloy under uniaxial tension and three-point bending were accurately predicted. The results showed that the peak bending force of the beams was proportional to the strength under different aging states, while stress triaxiality governed the cracking failure. Pre-aged and under-aged beams resisted cracking until reaching 250 mm displacement due to stress transition from tensile to compression on the bottom surface. The under-aged beam exhibited optimal energy absorption (7.86 kJ) and a higher peak force (38.75 kN).