两层弹性软基底中压电薄膜的屈曲分析

Buckling analysis of piezoelectric thin film sandwiched between two elastic soft substrates

硬薄膜软基底结构在压应力作用下通常会发生一种褶皱形式的屈曲失稳,这种结构在微纳机电系统、柔性电子器件等领域有非常广泛的应用。压电材料因其独特的力电耦合特性具有普通材料不可替代的作用,受到软基底-硬薄膜-软基底3层结构能进一步提高其弯曲性能的启发,从理论上分析了关于压电薄膜3层结构在压应力作用下的屈曲问题,结合线性扰动分析和能量法获得了3层结构压电薄膜屈曲的临界应变、波数、波长和幅值的解析表达式,并且与弹性薄膜3层结构进行了对比分析,发现压电薄膜比弹性薄膜有更强的抵抗屈曲变形能力。

The stiff film on a compliant substrate will wrinkle under applied compressive stress,this structure is widely used in the fields of micro-nano electromechanical systems,flexible electronic devices.Piezoelectric materials cannot be replaced because of its unique mechanical and electrical coupling characteristics with common materials.Inspired by that the bending performance for three-layer structure of soft substrate-hard film-soft substrate can be further improved,the buckling problem of a piezoelectric thin film three layers structure under the compressive stress is theoretically analyzed.The analytical expressions of the critical strain,wave number,wavelength and amplitude of the three-layer piezoelectric thin films are obtained by the linear perturbation analysis and the energy method.Compared with the three layer structure of the elastic thin film,it is found that the piezoelectric thin film is more capable of resisting the buckling than the elastic film.