基于区间非概率模型的热驱动柔顺机构可靠性拓扑优化

Reliability-based Topology Optimization of Thermally Actuated Compliant Mechanisms Based on Interval Non-probabilistic Model

摘要:

为了满足热驱动器可靠性要求，提出一种基于区间非概率模型的热驱动柔顺机构可靠性拓扑优化方法。采用区间非概率模型描述热载荷的不确定性，以输出位移构建可靠性功能函数，在可靠性指标约束条件下寻求机构体积最小化，建立基于区间非概率模型的热驱动柔顺机构可靠性拓扑优化模型，利用移动渐近线算法更新设计变量。与确定性优化结果相比，可靠性拓扑优化获得的热驱动柔顺机构体积有所增加，能够有效地满足可靠性指标约束，可靠性设计的热驱动柔顺机构输出位移上、下限理论值与有限元分析结果误差均小于5%，验证了设计方法有效性；并且分析了不同输出刚度和热载荷区间对热驱动柔顺机构可靠性拓扑优化结果的影响。

Abstract:

To meet the reliability requirements of thermal actuators, a method for reliability-based topology optimization of thermally actuated compliant mechanisms based on interval non-probabilistic model was proposed. The interval non-probabilistic model was adopted to describe the uncertainties of thermal load. The functional function was constructed by the output displacement of thermally driven compliant mechanisms. The objective function was used to minimize the volume of the thermally actuated compliant mechanisms, and the reliability index was used as the constraint. The model for reliability-based topology optimization of thermally actuated compliant mechanisms based on interval non-probabilistic model was established. The method of moving asymptotes was applied to update the design variables. Compared with the results of deterministic topology optimization, the volume of thermally actuated compliant mechanisms obtained by reliability-based topology optimization was increased, and the reliability index constraints can be effectively met. The theoretical results of thermally actuated compliant mechanisms obtained by reliability design had an error of less than 5% relative to the finite element analysis results. The effectiveness of the proposed design method for thermally actuated compliant mechanisms was demonstrated. The influence of different output stiffness and thermal load intervals on the results of reliability-based topology optimization of thermally actuated compliant mechanisms was analyzed.