Figure 7 (a-d).nb from Investigating wave propagation across loosely bonded interfaces in visco-piezo composites with flexoelectricity in LiNbo3 and AlN

This study compares the transference of surface seismic waves at the loosely bonded interface of a visco-piezo composite structure using two materials, lanthanum niobate (LiNbO3) and aluminium nitride (AIN). The structure comprises a viscoelastic layer bonded to a piezoelectric substrate, incorporating the flexoelectric effect. The shear response of the upper layer is modelled using three rheological models: Kelvin–Voigt, Maxwell and Newton. An analytical separable variable method is employed to derive complex dispersion relations for both electrically open- and short-circuit conditions. The numerical analysis focuses on the influence of key parameters, such as bonding conditions and interfacial parameters, on phase velocity and attenuation coefficients in both materials. Results indicate that AIN shows higher phase velocities, while LiNbO3 demonstrates a stronger impact on attenuation, particularly in the Kelvin–Voigt model. In addition, the flexoelectric effect significantly alters the wave behaviour in both materials, impacting both phase velocity and attenuation. This comparison reveals important differences in wave propagation behaviour, which is crucial for the development of devices like sensors, actuators and energy harvesters. The study offers new insights into piezo-flexo coupling and its potential applications in advanced piezoelectric systems.本研究针对黏弹性压电复合结构的弱结合界面，以铌酸镧（LiNbO3）与氮化铝（AIN）两种材料为研究对象，对比了表面地震波在该界面的传输特性。该复合结构由黏弹性层与压电基底结合而成，并引入了挠曲电效应。上层的剪切响应采用三种流变模型进行建模：开尔文-沃伊特（Kelvin–Voigt）模型、麦克斯韦（Maxwell）模型与牛顿（Newton）模型。本研究采用解析分离变量法，推导得到了电开路与电短路两种工况下的复色散关系。数值分析部分重点探究了结合状态、界面参数等关键参数对两种材料的相速度与衰减系数的影响规律。研究结果表明，氮化铝（AIN）具备更高的相速度，而铌酸镧（LiNbO3）对衰减的影响更为显著，尤其在开尔文-沃伊特模型中表现突出。此外，挠曲电效应对两种材料的波动行为均存在显著调控作用，同时影响相速度与衰减特性。本次对比揭示了两种材料在波传播行为上的显著差异，这对于传感器、执行器与能量收集器等器件的研发具有重要价值。本研究为压电-挠曲电耦合效应及其在先进压电系统中的潜在应用提供了全新的理论见解。