疲劳寿命约束下的连续体结构拓扑优化

    Continuum Topology Optimization With Fatigue Life Constraint

    • 摘要: 在连续体结构拓扑优化设计中,优化模型通常考虑强度、刚度、稳定性等力学性能.为研究在结构优化设计中疲劳特性对于结构拓扑的影响,基于独立、连续、映射(independent continuous mapping,ICM)拓扑优化方法,引入了疲劳寿命过滤函数,提出了连续体结构疲劳拓扑优化的模型和求解方法.建立以结构质量最小为目标、疲劳寿命为约束的连续体疲劳拓扑优化模型,通过将疲劳寿命约束转化为应力约束,对优化模型进行了求解.数值算例对比了不同刚度过滤函数、疲劳寿命过滤函数的系数,得到了过滤函数系数对结构质量与结构构型的影响规律;研究了疲劳寿命和应力分别作为约束时拓扑优化结果的差异性,给出了不同的循环外载荷工况情况下的算例,得出了随循环外载荷变化时的结构质量及结构构型.研究结果验证了连续体疲劳拓扑优化理论的有效性与可行性.

       

      Abstract: In topology optimization design for continuous structure, common mechanical properties are considered, such as structural strength, stiffness and stability. To investigate the influence of fatigue on structural topology in optimization design, filter function of fatigue life was introduced and then the model and solution method of fatigue topology optimization for continuous structures were proposed based on independent continuous mapping (ICM) method. With structure minimum weight as objective and the fatigue life as constraints, the fatigue topological optimization model was established and solved by transforming fatigue life constraint into stress constraint. The numerical examples verified the feasibility and effectiveness of theory of fatigue topology optimization. By comparing different coefficients of stiffness filter function and fatigue life filter function, influences from filter function coefficients on structural weight and structural configuration were obtained. Moreover, the differences of topological results were investigated using fatigue and stress as constraints, respectively, structural weight and structural configuration were obtained by giving numerical examples with different cyclic external loads cases. The results extend the ICM method and this basic theory provides a new idea for fatigue topology optimization of continuum structures.

       

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