A Process of Decoupling and Developing Body Structure for Safety Performance

This paper describes a novel approach of decoupling and developing local structures for crash performance . The process discussed here enables quick development of local structure to address packaging changes in a mass efficient manner. Hundreds of design choices compatible with other design constraints were evaluated to select the optimized design. Here optimum is defined as the design that met the required parameters (crashworthiness, NVH, package, manufacturability and robustness) at the minimum mass. A large number of choices could be evaluated by using a highly simplified simulation process, since the goal was often making an A-to-B choice at a local level, as opposed to predicting exact performance at a system level. The primary focus of mass reduction was efficiency of the load path strategy, and exploitation of the unique geometrical shapes feasible in the hydroforming process. The designs were also rendered robust through a Montecarlo Simulation process for manufacturing variations and small variations in angle of impact. A subset of the new design was incorporated into a vehicle, which was tested full-scale under the ODB format. Cost constraints prevented complete rebuilding of the load path. The optimized test vehicle had comparable performance when compared to the original design, although the mass of load carrying members was reduced by 20%.