智能材料MFC驱动双稳态板的跳变特性研究

Study on the Snap Characteristics of Bistable Plate Actuated by MFC Intelligent Material

智能可变形结构能感知周围环境的变化并做出适当的反应,其主要原理是利用智能材料层产生应变以达到驱动主体结构发生变形.含有智能材料压电纤维MFC的双稳态复合材料层合板可以通过智能驱动实时调整主体结构的形状,实现稳态构型之间的跳变.论文对中心点固支的MFC压电智能驱动双稳态复合材料层合板的稳态构型、跳变规律及其影响因素进行了系统地研究.研究内容主要包括:含MFC的双稳态层合板的稳态构型、分叉行为和驱动跳变分析.利用理论模型分析了层合板的长宽比、厚度尺寸、铺层方式和MFC粘贴位置对双稳态板分叉行为的影响,并预测了双稳态层合板的临界尺寸以及驱动跳变的临界电压.双稳态板的跳变是一个大变形的非线性行为,实现和控制跳变行为的研究是其应用的基础.论文的研究结果为新型压电材料驱动双稳态板的结构设计提供了一定的理论参考.

Due to the residual stress, asymmetric cross-ply bi-stable laminates can show two different stable deformation states at room temperature. In this paper, the stable configurations and the snap through behaviors of the bi-stable laminate actuated by MFC with center point fixed is studied. Considering the effect of mechanical-electric coupling, the mechanical model of the system is constructed. Based on the classical laminate theory of Krichhoff hypothesis, the potential energy of the system is obtained according to the Von-Karman strain-displacement relationship, and the Rayleigh-Ritz technique is used to obtain the configuration of the bi-stable laminate with MFC actuator. Using numerical method, systematic parametric analyses are conducted to investigate the influences of aspect ratio, ply thickness and laminate size on the bifurcation phenomenon of the bi-stable laminate with MFC. The critical size of bi-stable laminate and the snap-through voltage are predicted. It is found that the out-of-plane displacement of the corner point of the bi-stable laminate with MFC bifurcates with the increase of the side length of the laminate, and the bi-stable critical length increases with the increase of the aspect ratio. The critical thickness of the bi-stable laminate with MFC decreases with the increase of the aspect ratio. Using a specific MFC to actuate asymmetric laminates, there is a certain range of requirements for the size of the laminate. If the size of the laminate is too small, it will lose the bi-stable state, and if the size of the laminate is too large, it will exceed the actuating capability of the MFC. Compared with unidirectional actuating asymmetric laminates, adding MFC on the other side can achieve bidirectional actuating, but the snap-through voltage needs to increase. The snap through behavior of bi-stable laminates is a nonlinear behavior with large deformation, and the study of realization and control of snap behavior are very important for its application in engineering. Bi-stable laminate actuated by MFC is an intelligent deformable structure with fast response, easy control and strong reliability. The results of this paper provide a certain theoretical reference for the structural design of bi-stable laminates actuated by new piezoelectric materials.