Abstract: Pressure-actuated compliant mechanisms obtained by topology optimization are prone to de facto hinges,which may cause manufacturing difficulties.To meet the requirements of manufacturing process,a method for topology optimization of pressure-actuated compliant mechanisms with minimum length scale control was proposed.By using the improved solid isotropic material with penalization model,the fluid pressure loads was calculated with Darcy's law and the drainage term.The maximization of mutual strain energy and the minimization of strain energy for compliant mechanisms were developed as multi-objective functions.The skeleton features of compliant mechanisms were extracted by Otsu algorithm and topology refinement algorithm,and the minimum length scale control was constructed.The structural volume and minimum characteristic size were employed as constraints.The model for topology optimization of pressure-actuated compliant mechanisms with minimum length scale control was established.The method of moving asymptotes algorithm was employed to solve the optimization problem for designing pressure-actuated compliant mechanisms.The results of numerical examples showed that the minimum length scale of the pressure-actuated compliant mechanisms obtained by the proposed method could be effectively controlled,and the effect of different minimum length scale control limits on the results was investigated.

Key words: compliant mechanisms, pressure loads, topology optimization, minimum length scale control

摘要： 拓扑优化设计的压力驱动柔顺机构拓扑构型容易出现类铰链结构,导致难以制造加工。为了满足制造工艺要求,提出一种考虑最小尺寸控制的压力驱动柔顺机构拓扑优化设计方法。采用改进的固体各向同性材料惩罚模型,利用达西定律结合排水项计算流体压力载荷,以机构的互应变能最大化和应变能最小化为优化目标,采用Otsu算法和拓扑细化算法提取柔顺机构的骨架特征,从而构建最小特征尺寸控制,以结构体积和最小特征尺寸作为约束,建立考虑最小尺寸控制的压力驱动柔顺机构拓扑优化模型,采用移动渐近线算法进行压力驱动柔顺机构拓扑优化问题求解。数值算例结果表明,所提设计方法获得的压力驱动柔顺机构最小特征尺寸满足约束,能够有效地抑制类铰链结构,并且分析不同最小控制尺寸对柔顺机构拓扑优化结果影响规律。

关键词: 柔顺机构, 压力载荷, 拓扑优化, 最小尺寸控制