热机电耦合结构动力学及其主动控制的有限元分析

发布时间：2018-05-17 01:40

本文选题：热-机-电耦合 + 压电结构　；参考：《苏州大学》2014年硕士论文

【摘要】：本文采用8节点实体壳单元、电势沿厚度二次分布的压电单元以及等参热单元构造了热-机-电耦合单元。基于Hellinger-Reissner广义变分原理建立了热-机-电耦合的线性压电板壳动力学有限元模型。为克服梯形自锁、厚度自锁以及剪切自锁，进一步采用应力杂交元和ANS（Assumed Natural Strain）法。根据本文建立的有限元方程分别对压电片整体铺设和分片铺设结构的静态和动态问题进行数值计算，，确定外界载荷、电场、温度场对结构的力学性能的影响规律，主要是结构形变、模态、主动控制等力学性能。数值结果显示本文模型具有相当高的收敛性和精确性。通过对热流和电载荷联合作用对整片和分片铺设压电片结构的静动态特性的影响情况分析，得到在现有假设的前提下，热流作用仅影响机械场的载荷向量，电场影响机械场的刚度矩阵和载荷向量。在线性有限元模型的基础上，采用常增益负速度反馈控制方法对压电结构和热-机-电耦合结构导出了动力控制的有限元模型并进行了有效主动振动控制的数值计算。进一步采用了新的控制模式消除了温度场效应所引起的平衡位置的偏移。最后考虑几何非线性的耦合结构。采用增量分析法，建立有效的非线性热-机-电耦合结构的有限元模型。数值分析了非线性对结构的静态形变的影响，结果显示本文给出的非线性模型的有效性和精确性。
[Abstract]:In this paper, a thermal-mechanical-electric coupling element is constructed by using an 8-node solid shell element, a piezoelectric element with a quadratic distribution of potential along the thickness, and an isoparametric heat element. Based on the Hellinger-Reissner generalized variational principle, a thermo-mechanical coupled finite element model of piezoelectric plate and shell dynamics is established. In order to overcome trapezoidal self-locking, thickness self-locking and shear self-locking, the stress hybrid element and ANS(Assumed Natural training method were further used. According to the finite element equations established in this paper, the static and dynamic problems of piezoelectric monolithic and piecewise laying structures are numerically calculated, and the influence of external load, electric field and temperature field on the mechanical properties of the structure is determined. Structural deformation, modal, active control and other mechanical properties. Numerical results show that the proposed model has high convergence and accuracy. Based on the analysis of the influence of heat flux and electric load on the static and dynamic characteristics of the whole and segmented piezoelectric structure, it is obtained that the heat flux only affects the load vector of the mechanical field under the existing assumptions. The electric field affects the stiffness matrix and load vector of the mechanical field. Based on the linear finite element model, the finite element model of the dynamic control is derived by using the constant gain negative velocity feedback control method for piezoelectric structures and thermal-mechanical-electrically coupled structures, and the numerical calculation of the effective active vibration control is carried out. Furthermore, the new control mode is used to eliminate the equilibrium offset caused by the effect of temperature field. Finally, the coupled structure with geometric nonlinearity is considered. An effective finite element model for nonlinear thermo-mechanical coupled structures is established by incremental analysis. The effect of nonlinearity on the static deformation of the structure is numerically analyzed. The results show the validity and accuracy of the nonlinear model given in this paper.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535

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