智能结构中存在着复杂的弹性场

层合压电智能结构是由弹性材料,压电材料和粘结层构成,在层合压电智能结构中存在着复杂的弹性场、电场的相互耦合作用。因此建立能准确描述层合压电智能结构在外荷载作用下的静动态响应的分析模型,要进行力-电耦合行为的建模;力-电耦合的定量设计、优化设计与计算机模拟;探索力学场,电场的宏观场的耦合作用,讨论层状智能材料力-电耦合问题的计算理论和方法;层合压电智能结构的优化设计;研究传感层和致动层嵌置深度、厚度及位置的优化设计模型,建立嵌置有传感层和致动层的层合智能结构的优化设计的有限元分析模型和闭合反馈控制算法的理论公式,实现层合压电智能结构的静力分析、形状控制和主动控制,这些都是亟待解决的问题。本文研究的主要内容如下:(1)、层合压电智能结构的有限元方程推导和有限元分析模型建立。从Hamilton原理和磁电力热耦合的本构方程出发,通过引入对电场和弹性场适当的近似,建立层合压电结构的有限元分析模型和计算公式,编制基于ANSYS/APDL的有限元分析程序,为静力分析和主动控制做准备。(2)、层合压电智能结构的静力分析。在现有的压电有限元分析模型中,大部分都忽略了粘结层的影响,实际上粘结层对结构的性态是有影响的。建立能准确描述压电材料层合结构在外荷载作用下的弹性场、电场、和温度场的分布以及结构的感知和致动行为的有限元分析模型。重点揭示单点配置和多点配置压电片、以及不同粘贴与埋置方式对于结构致动性能和传感性能的影响。(3)、层合压电智能结构的优化设计。在层合压电智能结构中调整压电的电场和电压可以实现静力变形控制。早期层合智能结构的研究主要集中在传感层和致动层都附着在层合智能结构的表面。在这种情况下,附着在层合智能结构表面的传感层和致动层比较容易受到化学腐蚀和机械损坏。另一方面致动力的大小与压电层的厚度、嵌置位置和深度密切相关。随着智能结构动力学、材料科学以及电子技术的发展,在层合智能结构的制造过程中将传感层和致动层嵌置在层合结构内部在技术上已成为可能。(4)、层合压电智能结构的主动控制。本文研究了传感层和致动层嵌置深度、厚度及位置的主动控制模型,建立嵌置有传感层和致动层的层合智能结构的优化设计的有限元分析模型和闭合反馈控制算法的理论公式。数值研究主要集中研究不同叠层形式、材料性质和主动层的位置对层合压电智能结构振动响应的影响。本课题采用理论推导和有限元建模方法,科学地分析压电层合结构的静力问题、优化设计、形状控制和主动控制,开展层状压电结构的计算理论和方法的研究具有重要的科学意义和应用价值。
工业羊毛毡
Laminated piezoelectric smart structures consist of elastic materials, piezoelectric materials and bonding layers. The complicated inter-coupling effects between elastic and electric field exist in smart structures. Consequently, establishing analysis model that can accurately describe static-dynamic response of the laminated piezoelectric smart structures under external load, modeling the behavior of quantitative design, optimization and computer simulation of the electro-mechanical coupling; exploring the macroscopical field coupling of mechanical and electric field, discussing the computational theory and method of electro-mechanical coupling problem, optimizing laminated piezoelectric-magnetic smart structures, sensor and actuator layer depth, thickness and place, developing the finite element model and theory formula of laminated smart structures embedded sensor and actuator layers, carrying out the static analysis, shape control and active control. All these problems mentioned above are urgent to solve. The main contents of this paper are as follows:1. Finite element equation derivation and analysis model establishment of laminated piezoelectric smart structure. By properly approximating the electric and elastic field, the finite element analysis model and calculation formula of laminated piezoelectric structure are established according to Hamilton principle and magnetic-electro-mechanical-thermal constitutive equation. Programs are compiled based on ANSYS/APDL preparing for static analysis and active control.2. Static analysis of laminated piezoelectric smart structures. The effect of bonding layers was ignored in most of the existed piezoelectric FE model, although bonding layers have effect to structure indeed. So establishing the FE model that can accurately describe the distribution of elastic field, electric field and temperature field as well as the behavior of structure self-perception and action of laminated piezoelectric structure is very important.3. Optimization design of laminated piezoelectric smart structures. Adjusting the electric field and voltage of laminated piezoelectric structure will result in structure shape control. Early researches of smart structures were mainly concentrated in adhesive sensor and actuator layers. However, the adhesive sensor and actuator layers are prone to be chemically corrupted and mechanically damaged. The actuator force is closely related to embedded depth, thickness and place of piezoelectric sensor and actuator layers. The developments of smart structural dynamics and materials science have made it possible to embed piezoelectric sensor and actuator into structures.4. Active controlling of laminated piezoelectric smart structures. This paper researched the active control model involving embedded sensor and actuator depth, thickness and place, developed the finite element optimization design and theory formula of close loop feedback control algorithm of smart structure with embedded sensor and actuator layers. Numerical research is performed to the effect of different laminated form material property and vibration of actuator layer place response of laminated piezoelectric smart structures.The subject scientifically analyzed the static problem, optimization design, shape control and active control of laminated piezoelectric structures developing by of theoretical derivation and FE modeling method. It has great scientific significance and practical value to make research on the calculation theory and method of laminated piezoelectric smart structures.