变密度法在气缸体轻量化设计中的应用

Application of variable density method to light-weight design of cylinder block

将变密度拓扑优化方法应用于发动机气缸体轻量化设计中.以气缸体上施加最大爆发压力工况下的载荷为边界条件,以气缸体总柔度最小为优化目标,以气缸体体积比为约束条件,以单元密度为设计变量,对气缸体进行拓扑优化.对优化后的结构重新建模,分析了在最大爆发压力工况下的应力分布.结果表明,气缸体质量减轻了5 kg,最大主应力与优化前相当,整体应力分布更加均匀,达到了等强度设计的目的.将变密度法应用于气缸体的等强度轻量化设计,有助于确定气缸体的最佳形状,并减少重复设计验证的次数.

A variable density based topology optimization method was applied to the light-weight design of engine block. The topology optimization was performed with the load case of the maximum gas pressure as boundary condition, the minimum compliance of cylinder block as single objective, the volume ratio of cylinder block as constrain, and the material density as variable. After the model of the optimized cylinder block was rebuilt, the stress distribution of the new cylinder block was analyzed at the same load case. The results showed that although the cylinder block was reduced by 5 kg, the maximum principal stress was almost the same as that of the original one, and the stress distribution was more homogeneous, achieving the objective of equal-intensity design. Consequently the structure optimization used in the equal-intensity light-weight design can determine the best shape of cylinder block and decrease the repetitions of design and validation.