含SMA和PZT二元驱动器的智能复合材料结构形状控制

基于有限元素法求解嵌入SMA和PZT作为联合变形驱动器的板壳型智能结构的变形,采用优化方法将最小化目标变形和实际变形差作为目标函数,确定各个驱动器的驱动电压或控制温度以实现自适应结构的任意变形控制,并考虑到了控制电压和结构温度的限制。算例结果列举了联合控制同单独PZT或SMA控制方式的控制效果对比。      

压电梁振动的多输入多输出主动控制

对表面上贴有多个用作驱动器和传感器的压电陶瓷片的“压电梁”结构，导出了从驱动器到传感器的频响函数公式，作为压电结构设计和振动控制的数学模型。提出了压电梁对缓变周期扰动振动环境的多输入多输出振动抑制方法。     

Stiffness control of cylindrical shells under axial compression using piezocomposite actuators—An experimental investigation

The present study explores the modification and control of prebuckling stiffness of cylindrical shells for their potential use in smart structures. The effects of surface-bonded microfiber composite actuator patches on cylindrical shells subjected to axial compression are studied experimentally. The actuators are placed such that the distance separating them is less than the observed axial and circumferential buckling wavelengths. Strain gauge sensors are used to measure the axial strains at discrete locations on the cylindrical shell. Experimental results indicate that the actuation effect can reduce the local strains as well as improve the overall stiffness of the structure. The results obtained in this study potentially have a significant impact in space applications.     

温度梯度场中梁的形变控制研究

5介绍了一种新型的压电作动器—层叠式压电作动器,并使用这种作动器对温度场中的梁进行了形状控制研究。根据哈密顿原理,得到了粘贴有层叠式压电作动器的梁结构的控制方程,进行了数值仿真,并且用Comsol软件进行了模拟,两者的结果基本一致。对压电作动器的控制电压进行了优化,得到了最优控制电压。由于层叠式压电作动器的控制力与压电片的层数成二次函数关系,当控制电压恒定时,层叠式压电作动器的控制力随着压电器层数的增加而迅速减小。使用层叠式压电作动器可以在比其他作动器更小的电压下取得更好的控制效果。通过与普通压电作动器的比较,可以发现层叠式压电作动器可以有效地降低作动器的施加电压,而且可以显著增强控制效果。这种形状控制方法为应用层叠式压电作动器进行薄壁结构的形状控制提供了理论基础。     

压电悬臂梁的动力学建模与主动控制

为计及压电层的刚度特性,基于一阶剪切变形理论推导压电层合梁的抗弯刚度,由Hamilton变分原理建立压电层合梁的有限元模型,采用模态叠加方法对有限元模型降阶。在应变最大处配置制动器和传感器,基于鲁棒极点配置算法对低阶系统设计状态反馈,配置极点至期望位置。把针对低阶系统设计的控制器作用于原系统以实现振动主动控制。数值算例验证了这种力学建模方法和控制器设计方法的有效性。     

含压电作动器和传感器的复合材料层板静变形有限元分析和形状控制研究

本文研究了含压电作动器和传感器层的复合材料层板理论,建立了位移和电自由度的四节点有限元素,利用总势能最小原理推导了静力平衡方程,实现和验证了含压电作动器/传感器复合材料层板静态分析有限元程序。并对该类复合材料层板进行了形状控制研究。      

含压电片复合材料层合板的高阶计算模型

给出了一种分析含任意内埋压电片复合材料层合板的高阶耦合模型, 板的位移场采用三阶剪切理论, 并提出了压电片中电势场在厚度方向的三次分布模式, 可以更精确地描述力、电耦合作用下电场的非均匀分布。在平面应力的假设下给出了简化的压电材料本构方程, 推导了基于该模型的压电层合板有限元计算公式, 并对双压电片梁的弯曲和层合板的变形控制进行了计算, 压电梁的弯曲计算结果与解析结果吻合良好, 表明本文的模型和公式是精确有效的。     

含压电作动器和传感器的复合材料层板静变形有限元分析和形状控制研究

本文研究了含压电作动器和传感器层的复合材料层板理论，建立了位移和电自由度的四节点有限元素，利用总势能最小原理推导了静力平衡方程，实现和验证了含压电作动器／传感器复合材料层板静态分析有限元程序。并对该类复合材料层板进行了形状控制研究。     

压电陶瓷致动器的动态控制模型及逻辑规则控制

提出了一种新的压电陶瓷致动器的动态控制模型．该控制模型建立在泛布尔代数理论基础上;它依赖于压电陶瓷的控制经验．通过一系列控制规则,采用泛布尔代数的符号进行控制模型的表述．在所建模型基础上,结合PID控制器对压电陶瓷进行了Rule＋PI控制的离线仿真研究;仿真结果表明,该控制模型结构简单,控制方便,易于实现．     

压电智能结构振动控制中执行元件最优位置的选择

采用模态分析及控制理论,确定了定量度量模态对贮存在结构中能量积分贡献的方法。利用奇异值分解技术确定了定量度量模态可控程度的方法。以压电智能结构振动控制效果为目标,将两个度量指标加权结合,构造了一种新的度量压电智能结构可控程度的指标,并以此为选择压电执行元件最优位置的依据。最后给出数值示例说明文中方法的有效性     

Optimal shape control of functionally graded smart plates using genetic algorithms

This paper deals with optimal shape control of functionally graded smart plate containing patches of piezoelectric sensors and actuators. The genetic algorithm (GA) is designed to search for optimal actuator voltage and displacement control gains for the shape control of the functionally graded material (FGM) plates. The work extends the earlier finite element formulations of the two leading authors, so that it can be readily treated using genetic algorithms. Numerical results have been obtained to study the effect of the shape control of the FGM plates under a temperature gradient by optimising (i) the voltage distribution for the open loop control, and (ii) the displacement control gain values for the closed loop feedback control. The effect of the constituent volume fractions of zirconia, through varying the volume fraction exponent n, on the optimal voltages and gain values has also been examined.     

FINITE ELEMENT MODELLING OF STRUCTURES INCLUDING PIEZOELECTRIC ACTIVE DEVICES

Finite element modelling is used to study the response of plate structures on which piezoelectric active devices are mounted. Such devices are typically small in relation to the size of the structure which can be modelled as a plate or shell structure. In modelling the response of such devices, it is necessary to use a detailed model of the device but to do the same for the whole structure is computationally expensive and unnecessary. Full three-dimensional elements are used to model the piezoelectric devices because such devices are anisotropic, couple electric and elastic fields and satisfy boundary conditions independently on the two fields. Shell elements, approximated by many flat-shell elements are used in modelling the structure. Transition elements have been derived to connect the three-dimensional solid elements in the piezoelectric region to the flat-shell elements used for the plate. This approach has merits in terms of accuracy in modelling the piezoelectric device and computational economy for the plate structure. The use of shell elements is preferred for the structure since brick elements lead to unnatural stiffening of the plate and artificially high natural frequencies. The aspect ratio of the transition elements are first optimized through a numerical study and the sensor and actuator performance of the devices is then verified. © 1997 by John Wiley & Sons, Ltd.     

压电作动器对热变形层合板形状修复研究

基于一阶剪切效应Mindlin板理论,建立了在热载下含分布式压电作动器的复合材料层合板有限元分析模型和控制方程,分别研究了该板在内外表面存在温差的情况下的热变形,以及使用压电作动器对热变形区域进行形状修复的问题;在分析中考虑了压电作动器与复合材料层合板间含有胶接层的影响。由典型算例结果讨论,得到如下结论:1)使用压电作动器可以有效地对复合材料层合板的表面热变形形状进行修复;2)压电作动器的分布位置对修复效果影响很大;3)在电压达到一定数值后,继续增加电压值对修复效果贡献很小。