某电动客车车身骨架的轻量化

Lightweight on body frame of electric bus

为了满足某电动客车轻量化的需求,在保证车身骨架在模拟车辆行驶的4种极限工况(水平弯曲、极限扭转、紧急转弯和紧急制动)结构性能良好后,用灵敏度分析找出能有效减轻底盘骨架质量而对骨架结构性能影响不大的部件.以型材厚度作为优化设计变量值,骨架总质量最小为目标,各工况下的最大位移为约束条件,对车身骨架建立多目标优化数学模型.利用响应面算法(RSM)得到优化后各设计变量的厚度值.对轻量化前后的车身骨架在相同条件下进行了模态和结构性能对比分析.结果表明:优化后4种极限工况下的车身骨架强度与刚度均能得到保证,模态频率也在要求范围内,且车身骨架总质量减轻45.6 kg,约占其总质量的5.36%,轻量化效果较好.

To meet the demand of lightweight for an electric bus,the body frame simulation was ensured with good structural performance under four limit conditions of horizontal bending,ultimate torsion,emergency turn and emergency braking. By sensitivity analysis,the components of chassis frame were obtained to effectively reduce the quality with slight effect on the performance of chassis structure. With the profile thickness as design variables,the minimum total frame quality as goal and the maximum displacement under different working conditions as constraints, the multi objective optimization mathematical model of body frame was established. By response surface method（ RSM）,the design variables of the thickness values were obtained after the optimization. The model and the structure performance of lightweight body frame under the same conditions were comparatively analyzed. The results show that the strength and the stiffness of body frame can be guaranteed under four limit conditions,and the modal frequency is also within the required range. The total weight of body frame is reduced by 45. 6 kg,which is about 5. 36% of the total mass.