Topology Optimization of Multibody Systems Undergoing Dynamic Loading using an Equivalent Static Displacement Method

Structural topology optimization for vehicle structures under static loading is a well-established practice. Unfortunately, extending these methods to components subjected to dynamic loading is challenged by the absence of sensitivity coefficients: analytical expressions are unavailable and numerical approximations are computationally impractical. To alleviate this problem, researchers have proposed methods such as hybrid cellular automata (HCA) and equivalent static load (ESL). This work introduces a new approach based on equivalent static displacement (ESD). The proposed ESD method uses a set of prescribed nodal displacements, simulating the resultant reaction forces of a body subjected to dynamic loading, at different simulation time steps to establish the boundary conditions for each corresponding model—one model for each simulation time. A scalarized multi-objective function is defined considering all the models. A gradient-based optimizer is incorporated to find the optimal topology. Then, a new dynamic analysis is performed, the new ESD is defined for each model, and a new topology is obtained. The iterative process continues until convergence. Furthermore, this work also demonstrates the extension of the proposed ESD method in the topology optimization of multibody systems. To this end, the result shows an internal combustion engine's iterative topology optimization of the connecting rod and piston. Additionally, results from multiple load case problems have been presented to prove the effectiveness of the ESD methodology.