评介隋允康和彭细荣教授的专著《结构拓扑优化ICM方法新进展——概念深化及理论拓展》,其中ICM(independent continuous and mapping)意思是独立、连续和映射,该方法是结构拓扑优化的主流研究方法之一。该书借助于鉴史(力学史)和驭法(...评介隋允康和彭细荣教授的专著《结构拓扑优化ICM方法新进展——概念深化及理论拓展》,其中ICM(independent continuous and mapping)意思是独立、连续和映射,该方法是结构拓扑优化的主流研究方法之一。该书借助于鉴史(力学史)和驭法(方法论),总结了自2014年以来ICM方法的发展成果:深入阐述了ICM方法的阶跃函数的离散本质及对其光滑逼近的近似连续本质、逼近的快慢特性和多种映射策略;介绍了ICM方法的数学基础、求解算法和本体理论等方面的拓展性研究成果,包括可分离凸规划转换为求解对偶规划显式模型(dual programming-explicit model,DP-EM)解法、互逆规划理论及其优化应用等;探讨了该领域忽视的结构拓扑优化合理化建模问题;发展了包含疲劳寿命性能的局部性能约束的结构拓扑优化解法;归纳了破损-安全设计理论的演化,给出了位移、应力及频率约束的破损-安全拓扑优化问题的建模及求解;移植ICM方法至国际上广泛应用的变密度方法中。该书可供结构优化领域从事科研的师生和技术人员借鉴和参考。展开更多
Flexoelectricity refers to the link between electrical polarization and strain gradient fields in piezoelectric materials,particularly at the nano-scale.The present investigation aims to comprehensively focus on the s...Flexoelectricity refers to the link between electrical polarization and strain gradient fields in piezoelectric materials,particularly at the nano-scale.The present investigation aims to comprehensively focus on the static bending analysis of a piezoelectric sandwich functionally graded porous(FGP)double-curved shallow nanoshell based on the flexoelectric effect and nonlocal strain gradient theory.Two coefficients that reduce or increase the stiffness of the nanoshell,including nonlocal and length-scale parameters,are considered to change along the nanoshell thickness direction,and three different porosity rules are novel points in this study.The nanoshell structure is placed on a Pasternak elastic foundation and is made up of three separate layers of material.The outermost layers consist of piezoelectric smart material with flexoelectric effects,while the core layer is composed of FGP material.Hamilton’s principle was used in conjunction with a unique refined higher-order shear deformation theory to derive general equilibrium equations that provide more precise outcomes.The Navier and Galerkin-Vlasov methodology is used to get the static bending characteristics of nanoshells that have various boundary conditions.The program’s correctness is assessed by comparison with published dependable findings in specific instances of the model described in the article.In addition,the influence of parameters such as flexoelectric effect,nonlocal and length scale parameters,elastic foundation stiffness coefficient,porosity coefficient,and boundary conditions on the static bending response of the nanoshell is detected and comprehensively studied.The findings of this study have practical implications for the efficient design and control of comparable systems,such as micro-electromechanical and nano-electromechanical devices.展开更多
基金This work was supported by the Le Quy Don Technical University Research Fund(Grant No.23.1.11).
文摘Flexoelectricity refers to the link between electrical polarization and strain gradient fields in piezoelectric materials,particularly at the nano-scale.The present investigation aims to comprehensively focus on the static bending analysis of a piezoelectric sandwich functionally graded porous(FGP)double-curved shallow nanoshell based on the flexoelectric effect and nonlocal strain gradient theory.Two coefficients that reduce or increase the stiffness of the nanoshell,including nonlocal and length-scale parameters,are considered to change along the nanoshell thickness direction,and three different porosity rules are novel points in this study.The nanoshell structure is placed on a Pasternak elastic foundation and is made up of three separate layers of material.The outermost layers consist of piezoelectric smart material with flexoelectric effects,while the core layer is composed of FGP material.Hamilton’s principle was used in conjunction with a unique refined higher-order shear deformation theory to derive general equilibrium equations that provide more precise outcomes.The Navier and Galerkin-Vlasov methodology is used to get the static bending characteristics of nanoshells that have various boundary conditions.The program’s correctness is assessed by comparison with published dependable findings in specific instances of the model described in the article.In addition,the influence of parameters such as flexoelectric effect,nonlocal and length scale parameters,elastic foundation stiffness coefficient,porosity coefficient,and boundary conditions on the static bending response of the nanoshell is detected and comprehensively studied.The findings of this study have practical implications for the efficient design and control of comparable systems,such as micro-electromechanical and nano-electromechanical devices.
