Nondestructive Mechanical Contact Impedance and Compliance Testing of Rubberlike Materials

This paper is dedicated to the problems of nondestructive testing of rubberlike materials. A new method which we call an audiosonic contact impedance evaluation is developed. It is based on mechanical contact impedance evaluation (MCIE) at the local contact area between a piezo active sensor and specimen. A theoretical model consisting of quasistatically loaded and consequently connected dissipative Voigt's elements is discussed and solved analytically. A resonance equation used for MCIE at the local contact area consists of two impedances: mechanical impedance of PZT sensor and mechanical impedance of the specimen. Analytical results are compared with the results obtained from the simulation using the finite element method (FEM). Simultaneous measurements of the contact impedance and compliance associated with rubberlike materials having different hardnesses are accomplished by the multilayered piezo active sensor. A dynamic response obtained from the experimental sensor highly correlates with mechanical and rheological parameters.