Optimization Design of the Structure of the Automobile Bonnet Made of Fiber Composite Material

In this research, carbon fiber and glass fiber reinforced materials were used to conduct the empirical laminate design, sample manufacturing and modal experiment for the automobile bonnet. The experimental results were compared with the metal parts. The results showed that the fiber reinforced bonnet can not only meet the requirements of stiffness and modal, but also effectively reduced the weight, with a lightweight ratio of 51.2%. In different working conditions, the finite element method was used to analyze the modal and stiffness of the bonnet and compared with the metal parts to verify the effectiveness of the design. Based on the finite element model, according to the top-down design process, a new composite material structure optimization method was adopted, which used the finite element optimization technology. This method was divided into three stages: concept design, system design and detail design. The research showed that the new optimization design scheme can ensure the modal and stiffness of the automobile bonnet meet the requirements. At the same time, the lightweight effect was more obvious, which further reduced the weight of the automobile bonnet by 18% compared with the experiential laminate composite material.