Fatigue damage evaluation on austenitic stainless steel using nonlinear ultrasonic method

Abstract

The closed crack and micro damage are liable to be underestimated in conventional (linear) ultrasonic nondestructive testing, which lead to unpredictable safety hazards. The objective of this work was to detect the fatigue damage in the stainless steel samples by use of nonlinear ultrasonic method. In the first, the macro cracks of fatigue specimens were measured by metallographic method. Secondly, the finite amplitude method of nonlinear ultrasonic testing was employed to evaluate the