Conform and non-conformal contact problem in the face of piezoelectric motors can be hard to grasp, especially both the friction drive and wear lifespan are considered. Flowing the classical contact issue, an elastic brittle flat punch as the driving tip of the stator for piezoelectric devices is chosen and the contact behaviour under elliptical ultrasonic vibration is investigated using finite element method. A limited stress analysis is conducted after the quasi-static contact of the driving tip and the slider of the linear ultrasonic motors. After the analytical traces and experimental test on the fracture failure induced by the stress actions, the failure criteria of the elastic brittle driving tip are discussed. Results show that this quasi-static method can be applied to the complex contact analysis of an elliptical vibration device, and the failure characteristics induced by stress and strain can be obtained by FEM simulation and experiment verification. The pre-fracture stress map provides an important basis for the design of the geometrical mutation edge (e.g. edge fillet) of the elastic brittle punch and the composite structure for strength capacity. The failure analysis of brittle materials under ultrasonic vibration requires attention on quasi-brittle and quasi-plastic strength criterions. This study focus on determination of the contact stresses and the limited states during the elliptical vibration of a stator tip against slider. It also is important for the analysis on failure modes of frictional materials of ultrasonic devices, fretting wear of high-frequency connecting parts and machining process assisted with ultrasonic vibration.

压电电机面对的共形和非共形接触问题很难掌握，尤其是摩擦驱动和磨损寿命都被考虑在内。针对经典的接触问题，选择弹性脆性平冲头作为压电器件定子的驱动尖端，并使用有限元方法研究椭圆超声振动下的接触行为。在驱动尖端与线性超声波马达的滑块准静态接触后进行有限应力分析。在对应力作用引起的断裂破坏进行分析轨迹和实验测试后，讨论了弹性脆性驱动尖端的破坏准则。结果表明，该准静态方法可以应用于椭圆振动装置的复杂接触分析，应力应变引起的失效特征可以通过有限元模拟和实验验证得到。断裂前应力图为弹性脆性冲头几何突变刃口（如棱角）的设计和强度能力的复合结构设计提供了重要依据。脆性材料在超声振动下的破坏分析需要关注准脆性和准塑性强度准则。本研究的重点是确定定子尖端对滑块的椭圆振动期间的接触应力和限制状态。对超声器件摩擦材料的失效模式、高频连接件的微动磨损和超声振动辅助加工过程的分析也具有重要意义。