A comparative study of piezoelectric unimorph and multilayer actuators as stiffness sensors via contact resonance

• Published in: Acta mechanica Sinica Vol. 32; no. 4; pp. 633 - 639
• Main Authors: Fu, Ji, Li, Fa-Xin
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences 01.08.2016; State Key Laboratory for Turbulence and Complex System, College of Engineering, Peking University, Beijing 100871, China
• Subjects: Bimorphs; Classical and Continuum Physics; Computational Intelligence; Contact; Engineering; Engineering Fluid Dynamics; Impedance method; Multilayers; Piezoelectric actuators; Piezoelectricity; Research Paper; Sensors; Stiffness; Theoretical and Applied Mechanics; 传感器; 共振; 单层; 压电式; 压电致动器; 基础刚度; 工作原理; 接触刚度; Stiffness sensor; Piezoelectric actuator; Contact resonance
• ISSN: 0567-7718; 1614-3116
• DOI: 10.1007/s10409-015-0540-4

Piezoelectric bar-shaped resonators were proposed to act as hardness sensors in the 1960 s and stiffness sensors in the 1990 s based on the contact impedance method.In this work, we point out that both multilayer and unimorph（or bimorph） piezoelectric actuators could act as stiffness/modulus sensors based on the principle of mechanical contact resonance. First, the practical design and the performance of a piezoelectric unimorph actuator–based stiffness sensor were presented. Then the working principle of piezoelectric multilayer actuator–based stiffness sensors was given and verified by numerical investigation. It was found that for these two types of resonance-based sensors, the shift of the resonance frequency due to contact is always positive, which is different from that of the contact impedance method. Further comparative sensitivity study indicated that the unimorph actuator–based stiffness sensor is very suitable for measurement on soft materials, whereas the multilayer actuator–based sensor is more suitable for hard materials.