Analysis and optimization of the front subframe of vehicle

Abstract

As an important load-bearing part of the automobile chassis, the subframe is connected to the body and suspension system, and it is of great significance to perform the research on subframe lightweighting to improve the ride comfort and handling stability of the automobile. In order to comprehensively reflect the influence of operating conditions on the subframe, and at the same time consider the performance requirements such as strength and modal, the lightweight design of the subframe was performed with the combination of multi-condition topology optimization and multi-objective optimization methods. A rigid-flexible coupled multibody dynamic model of the front suspension was constructed to extract the loads at each articulation point of the subframe under multiple working conditions. Furthermore, the subframe was optimized for multi-condition topology in combination with the compromise programing method. Subsequently, the subframe was reconstructed based on the topology optimization results and a radial basis function (RBF) neural network approximation model was constructed using the optimal Latin hypercube tests. Then, the NSGA-II algorithm was adopted for multi-objective optimization of the reconstructed subframe. The optimized front subframe satisfies the performance requirements with the first-order frequency increased by 4 Hz, a weight reduction of 2.5 kg, the lightweight rate reaches 9.1%.