Abstract: To realize the feasibility and efficiency of continuum structural optimization,an optimization method based on local characteristics of substructure was proposed.Starting from the sub-functions of optimization process and the analysis on geometric features of continuum structure,the continuous structure was divided into parametric substructure,super-element substructure and state variable substructure.By choosing the geometric features of parametric substructure as the design variables,the optimized posture evaluation model was established to minimize continuous structure mass with requirements of stress and strain,which were made of the maximum stress and strain of the continuous structure supported by the parametric substructure and the state variable substructure.The local structure which implied the unchangeable local geometry of whole structure and the exclusive desired state variables named the super-element substructure.The model was solved by the sequential quadratic programming based on gradient.As the illustrative examples,the analysis and optimization were preformed through the continuous structural optimization of diesel engine piston,the reasonableness and superiority of proposed method were illustrated by comparing with the traditional methods at the convergence and efficiency.

Key words: local characteristics, substructure method, super-element, continuous structural optimization, diesel engine piston

摘要： 为了实现连续结构优化的可行性和高效性,提出一种基于局部特征子结构的优化方法。从优化过程的各个子功能和连续结构的几何特征分析出发,将连续结构划分为参数化子结构、超单元子结构和状态变量子结构,以参数化子结构的几何特征为设计变量建立连续结构评价的目标函数;以最小的连续结构质量为优化目标,将参数化子结构和状态变量子结构所承载的连续结构应力应变作为约束条件,建立连续结构评价的最优化数学模型,其中隐含着整体结构局部几何不变而且不包含所需状态变量的局部构造,即超单元子结构。采用基于梯度的序列二次规划法对模型进行求解。以某柴油机活塞连续结构优化为例进行分析优化,并从收敛性和高效性方面与传统优化方法进行比较,说明了所提方法的合理性和优越性。

关键词: 局部特征, 子结构法, 超单元, 连续结构优化, 柴油机活塞