Determination of Elastic modulus of thin materials by Speckle Interferometry

摘要

The paper proposes a sonic resonance test for an elastic modulus measurement which is based on speckle pattern interferometry (SPI). Previous measurement technique of elasticconstant has the limitation of application for thin film or polymer material because contact to specimen affects the result. Speckle pattern interferometry (SPI) has been developed as a noncontact optical measurement technique which can visualize resonance vibration mode shapes with whole-field. The maximum vibration amplitude at each vibration mode shape is a clue to find the resonance frequencies. The dynamic elastic constant of test material can be easily estimated from vibration of a beam equation using the measured resonance frequencies. The proposed technique is able to give high accurate elastic modulus of materials through a simple experiment set up and analysis. The result also compared to the theoretical result. In this paper, the basic principles of the technique are described briefly.