비선형 탄성-음향 효과를 이용한 비선형 탄성 계수의 계측과 금속재료의 특성평가

Measurement of Nonlinear Elastic Constants and Material Characterization by Using Nonlinear Elasto-acoustics

In this paper, a new method to estimate stress status in metal nondestructively by using nonlinear dependency of sound speed on stress is proposed. For the purpose, equivalent nonlinear elastic constants up to fourth-order are introduced and a new characteristic parameter given as a function of these constants is presented. And a concrete system to measure the characteristic parameter is constructed by electromagnetic pumping wave and ultrasonic probing wave system. Some experimental results for Al alloy showed that the estimation of stress status in metal is possible by the proposed method.