Abstract: To achieve the lightweight of the engine hood while ensuring its stiffness and strength and other performance, a multi-variable coupling multi-objective optimization method was adopted. The engine hood with carbon fiber outer panel and metal inner panel was designed. Based on the principle of equal stiffness, the initial thickness of the carbon fiber outer panel of the engine hood was determined. The metal plate was restructured based on topology optimization, and three inner panel structure schemes were obtained. Considering the influence of inner panel material, inner panel structure, inner panel thickness and carbon fiber outer panel ply thickness on the performance of the engine hood, Latin hypercube sampling was used, and on this basis, a radial basis function (RBF) neural network surrogate model was constructed for multi-variable coupling multi-objective optimization. To obtain the best carbon fiber ply sequence, the ply sequence of the outer panel was optimized in OptiStruct. The optimization results show that the static performance of the designed engine hood system meets the design requirements, and the mass is reduced by 51.27% compared with the original engine hood.

Key words: engine hood, topology optimization, lightweight design, composite materials