Body reinforcement design of suspension mounting point under dynamic loads using multi-objective topology optimization

Abstract

This paper presents a multi-objective topology optimization process for the body structure of the suspension mounting point to determine the optimum configuration that reduces the acceleration under external dynamic loads. As it is difficult to avoid the excitation force that occurs inside or outside the vehicle while driving, it is important to install a reinforcing structure in the vehicle to decrease the vibration that can directly affect the ride comfort of occupants. However, when a dynamic load is considered in the topology optimization problem, it is difficult to determine the optimum reinforcing bracket configurations because the material distribution is not always continuous, and the design variables converge to intermediate values that make the optimum design representation ambiguous. Discontinuous and unclear design tends to occurs more in dynamic load problems since the distribution of material in a design domain mostly affects the dynamic performance. Moreover, the objective function results would be worsened or enhanced depending on how the design space is defined. Therefore, it is necessary to develop a systematic process to derive an optimized design that not only enhances performance but is also suitable for manufacturability. Accordingly, an optimum reinforcing bracket configuration was obtained via a systematic approach. The area connected to nearby components is determined via sequential optimization, and both dynamic and static loads are simultaneously considered in the multi-objective optimization to derive a continuous design. The material distribution trend in the design space is investigated from the obtained designs, and the final design is modeled using shell elements considering manufacturability. It was confirmed that within a limited amount of material, the overall vehicle acceleration could be reduced.