Nondestructive Evaluation for Artificial Degraded Stainless 316 Steel by Time-Frequency Analysis Method

J. Ocean Eng. Technol. 2001;15(3):87-92.

Nam Ki-Woo,Kim Young-Un

Division of Materials Science and Engineering Pukyong National University,Korea Institute of maritime and Fisheries Technology

Keywords: Nondestrustive evaluation, Artificially degraded material, Sound velocity, Attenuation, Joint-time frequency analysis, Short time fourier transform and wigner-Ville distribution

Abstract

In this studies, joint time-frequency analysis techniques were applied to analyze ultrasonic signals in the degraded austenitic 316 stainless steels, to study the evolution of damage in these materials. It was demonstrated that the nonstationary characteristics of ultrasonic signals could be analyzed effectively by these methods. The WVD was more effective for analyzing the attenuation and frequency characteristics of the degraded materials through ultrasonic. It is indicated that the joint time-frequency analysis, WVD method, should also be useful in evaluating various damages and defects in structural members.