汽车薄壁冲压件焊点的拓扑优化

Topological optimization of spot-weld for thin-walled punched structures of automobile

汽车薄壁冲压件的焊点数量是汽车制造成本的决定性因素,为了降低成本,焊点的拓扑优化逐渐成为人们关注的热点。基于ICM(Independent Continuous Mapping,即独立、连续、映射)方法,将焊点有无的离散拓扑优化问题转化为[0,1]区间上的连续优化问题;建立了以结构刚度最大为目标、结构强度为约束的连续拓扑优化模型;采用K-S函数将多目标和多约束问题转化为单目标和单约束问题;运用响应面(RSM)方法将位移和应力转化为设计变量的显式函数,采用序列二次规划(SQP)方法求解优化模型。为了提高求解效率,对优化问题的可并行性进行了分析,搭建并行环境,用C++和Fortran语言开发了焊点优化问题的并行程序。工程实例表明,优化算法和程序是可靠、有效的。

The number of spot-weld of thin-walled punched structures of automobile has important impacts on the automotive manufacturing cost.In order to reduce the cost,topological optimization of the spot-weld is becoming a hotspot.Based on the ICM （Independent Continuous Mapping）method,the discrete topological optimization problem about spot-weld＇s existence or not is transformed into the continuous optimization problem on [0,1].The optimization model is founded with maximizing the structural stiffness as objective and structural strength as constraints.The problem of multi-objectives and multi-constraints is transformed into the problem of single-objective and single-constraint with the K-S function.The displacement and stress are transformed into the explicit function of design variables with the Response Surface Methodology （RSM）.The optimization model is solved with Sequential Quadratic Program（SQP）.To improve solution efficiency,the feasibility of the optimization problem is analyzed to found the parallel environment,and the parallel program of spot-weld optimization is exploited with C＋＋ and Fortran languages.The engineering practice shows that the optimization algorithm and program is feasible and efficient.