SMC材料发动机罩的多工况分析及优化研究

Analysis and Optimization of SMC Engine Hood Under Multiple Operating Conditions

SMC材料凭借良好的力学性能、轻量化、耐腐蚀性能等优点,在汽车结构设计中的应用逐渐增多。对某车型发动机罩开展SMC材料替代传统钣金结构的研究,即发动机罩内板、外板采用SMC材料,采用粘胶工艺替代包边、点焊工艺。但经仿真分析发现,SMC发动机罩存在整体刚度不足的问题。通过多学科优化工具对SMC发动机罩开展多工况结构优化,即将发动机罩外板、内板的各安装点区域和中间支撑梁区域进行分块处理,以每个分块的板厚为设计变量,模态和位移值为约束条件,以发动机罩总质量为优化目标进行多工况下的板厚尺寸优化。从优化结果来看,厚度调整后的SMC发动机罩在模态和其他刚度性能均能够满足性能要求,并且减重0.8 kg。

SMC material with good mechanical properties,lightweight,corrosion resistance and other advantages enjoys increasing application in automotive structure design.SMC material is used to replace traditional sheet metal structure in a certain type of engine hood,that is,SMC material is used in the inner and outer panels of the engine hood,and viscose process is used to replace the edging and spot welding process.However,it is found by simulation that SMC engine hood has insufficient stiffness.Multi-disciplinary optimization tools are used to optimize the structure of the SMC engine hood under multiple working conditions,that is,the installation point areas of the outer and inner plates of the engine hood and the middle support beam area shall be divided into blocks.The plate thickness of each block is used as the design variables,modal and displacement values as constraint,and the minimum weight as the goal,for the thickness size optimization.From the optimization results,the SMC engine hood with adjusted thickness can meet the performance requirements in mode and other stiffness,and the weight is reduced by 0.8 kg.