A hybrid quasi-static/dynamic process for forming large sheet metal parts from aluminum alloys

Auto makers interested in building aluminum bodies are in need of a competent technology that can successfully manufacture complex aluminum sheet components within the production constraints of the industry. A hybrid process consisting of a conventional, global quasi-static pre-form phase and local dynamic high velocity forming events is offered as a technically feasible and economically attractive solution to the formability problems attendant to aluminum auto body panels. The combination of conventional matched tool forming with electromagnetic pulse forming (MT-EM) was chosen as the best candidate for near term development.; Coupon experiments were conducted to investigate the interaction between quasi-static forming strains and the subsequent limit strains generated at high velocities. The positive results of these experiments led to application trials involving full size auto body parts. The results of the experiments and trials are reported along with an approximate method for initial design of the process components and estimation of energy requirements. For the purpose of detailed analysis of the process, numerical method codes are identified that are capable of modeling the conventional phase. GEM, a compact hydrodynamic code base on the smoothed particle (SPH) method, was chosen for modeling the electromagnetic pulse forming phase. A simple model of the test coupon system was written and the simulation results are compared to the actual coupon test data.