A combined shape and topology optimization algorithm based on isogeometric boundary element method for 3D acoustics is developed in this study.The key treatment involves using adjoint variable method in shape sensitiv...A combined shape and topology optimization algorithm based on isogeometric boundary element method for 3D acoustics is developed in this study.The key treatment involves using adjoint variable method in shape sensitivity analysis with respect to non-uniform rational basis splines control points,and in topology sensitivity analysis with respect to the artificial densities of sound absorption material.OpenMP tool in Fortran code is adopted to improve the efficiency of analysis.To consider the features and efficiencies of the two types of optimization methods,this study adopts a combined iteration scheme for the optimization process to investigate the simultaneous change of geometry shape and distribution of material to achieve better noise control.Numerical examples,such as sound barrier,simple tank,and BeTSSi submarine,are performed to validate the advantage of combined optimization in noise reduction,and to demonstrate the potential of the proposed method for engineering problems.展开更多
基于多材料变密度拓扑优化方法提出了一种密度指数函数插值的有序多材料性能近似(ordered exponential approximation of material properties, ordered-EAMP)模型,数学性质以及算例表明,与传统的SIMP/RAMP插值相比,该模型具有计算稳定...基于多材料变密度拓扑优化方法提出了一种密度指数函数插值的有序多材料性能近似(ordered exponential approximation of material properties, ordered-EAMP)模型,数学性质以及算例表明,与传统的SIMP/RAMP插值相比,该模型具有计算稳定,收敛速度快,优化结构灰度单元少的特点。在优化准则(OC)法求解变密度拓扑优化模型时,构造了一种适用于多材料的密度过滤格式,算例表明:可以有效减少灰度单元,且降低了优化的目标函数值。运用MATLAB-ANSYS联合优化,实现三类热边界条件下复杂热环境的多材料传热结构拓扑优化。相比于高热传导系数的单材料结构,多材料传热拓扑优化结构由于各种热传导系数材料的优化分布,结构的传热势容耗散更小,算例4中对比分析降低了20.3%,传热效率更高。展开更多
当前,直流变压器是解决直流输电系统互联时电压等级不一致问题的主要方法,但传统的直流变压器中含有交流变压器因而价格昂贵。对此文中提出了一种无需交流变压器的模块化组合式直流变压器(modular combined DC transformer,MCT)。文中...当前,直流变压器是解决直流输电系统互联时电压等级不一致问题的主要方法,但传统的直流变压器中含有交流变压器因而价格昂贵。对此文中提出了一种无需交流变压器的模块化组合式直流变压器(modular combined DC transformer,MCT)。文中首先分析了MCT的拓扑结构和工作原理,然后根据MCT的性能要求提出了参数的选择原则,最后在PSCAD研究了含有MCT的直流输电系统仿真模型。时域仿真结果验证了文中所提出的MCT的可行性。展开更多
涡轮机组合循环(Turbine based combined cycle,TBCC)发动机控制系统通信网络拓扑结构是其分布式控制系统方案设计的重要部分,优化网络拓扑结构可提高发动机推重比和控制系统可靠性。本文基于智能优化算法提出TBCC分布式控制系统网络拓...涡轮机组合循环(Turbine based combined cycle,TBCC)发动机控制系统通信网络拓扑结构是其分布式控制系统方案设计的重要部分,优化网络拓扑结构可提高发动机推重比和控制系统可靠性。本文基于智能优化算法提出TBCC分布式控制系统网络拓扑结构优化方法。基于图论建立TBCC几何模型和网格模型,以重量和可靠性为优化性能指标,同时考虑发动机表面高温区域以及控制节点的工作可靠性,分别采用粒子群算法和遗传算法优化星形结构中智能中央节点位置、中央节点的环形拓扑结构,获得星形-环形混合拓扑结构。仿真实例表明,基于本文方法优化所得的混合拓扑结构相较于星形集中式控制结构,系统重量降低了51.9%。展开更多
基金This study was financially supported by the National Natural Science Foundation of China(NSFC)under Grant No.11772322the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDB22040502.
文摘A combined shape and topology optimization algorithm based on isogeometric boundary element method for 3D acoustics is developed in this study.The key treatment involves using adjoint variable method in shape sensitivity analysis with respect to non-uniform rational basis splines control points,and in topology sensitivity analysis with respect to the artificial densities of sound absorption material.OpenMP tool in Fortran code is adopted to improve the efficiency of analysis.To consider the features and efficiencies of the two types of optimization methods,this study adopts a combined iteration scheme for the optimization process to investigate the simultaneous change of geometry shape and distribution of material to achieve better noise control.Numerical examples,such as sound barrier,simple tank,and BeTSSi submarine,are performed to validate the advantage of combined optimization in noise reduction,and to demonstrate the potential of the proposed method for engineering problems.
文摘基于多材料变密度拓扑优化方法提出了一种密度指数函数插值的有序多材料性能近似(ordered exponential approximation of material properties, ordered-EAMP)模型,数学性质以及算例表明,与传统的SIMP/RAMP插值相比,该模型具有计算稳定,收敛速度快,优化结构灰度单元少的特点。在优化准则(OC)法求解变密度拓扑优化模型时,构造了一种适用于多材料的密度过滤格式,算例表明:可以有效减少灰度单元,且降低了优化的目标函数值。运用MATLAB-ANSYS联合优化,实现三类热边界条件下复杂热环境的多材料传热结构拓扑优化。相比于高热传导系数的单材料结构,多材料传热拓扑优化结构由于各种热传导系数材料的优化分布,结构的传热势容耗散更小,算例4中对比分析降低了20.3%,传热效率更高。
文摘当前,直流变压器是解决直流输电系统互联时电压等级不一致问题的主要方法,但传统的直流变压器中含有交流变压器因而价格昂贵。对此文中提出了一种无需交流变压器的模块化组合式直流变压器(modular combined DC transformer,MCT)。文中首先分析了MCT的拓扑结构和工作原理,然后根据MCT的性能要求提出了参数的选择原则,最后在PSCAD研究了含有MCT的直流输电系统仿真模型。时域仿真结果验证了文中所提出的MCT的可行性。
文摘涡轮机组合循环(Turbine based combined cycle,TBCC)发动机控制系统通信网络拓扑结构是其分布式控制系统方案设计的重要部分,优化网络拓扑结构可提高发动机推重比和控制系统可靠性。本文基于智能优化算法提出TBCC分布式控制系统网络拓扑结构优化方法。基于图论建立TBCC几何模型和网格模型,以重量和可靠性为优化性能指标,同时考虑发动机表面高温区域以及控制节点的工作可靠性,分别采用粒子群算法和遗传算法优化星形结构中智能中央节点位置、中央节点的环形拓扑结构,获得星形-环形混合拓扑结构。仿真实例表明,基于本文方法优化所得的混合拓扑结构相较于星形集中式控制结构,系统重量降低了51.9%。
