Abstract: Aiming at the problem of self-weight of a micro-electric commercial vehicle, the structure size and bearing capacity of a micro-electric commercial vehicle frame were studied and then a lightweight optimization design idea for the frame of electric commercial vehicle was proposed. A mathematical model with the minimum beam mass as the objective function and the boundary condition, strength, stiffness and stability of the beam section size as the constraints was established. The optimization of the cross-section dimensions of the frame beam was realized by the simulated annealing intelligent algorithm toolbox in Matlab, and the optimal cross-section dimensions of the frame beam were obtained. The CATIA software was used to establish the 3D model before and after the frame optimization, and the ANASYS Workbench software was introduced to establish the finite element model. Based on this, static analysis (full load bending and full load torsion) and modal analysis were performed. The results indicate that the weight of the optimized frame is reduced by 13.43% compared with that before. The stress and deformation of the optimized frame meet the service conditions of material Q235 steel. The low-order free mode frequency before and after the frame optimization has only a small overlap with the road surface excitation frequency, the coincidence rate is only 4.8%, and the possibility of resonance is small. The lightweight optimization design idea is reasonable.
Key words: electric vehicle; lightweight; frame; optimized design; simulated annealing; finite element analysis