Fatigue Crack Propagation Behavior and Degradation Characteristics of STS316L by Nondestructive Evaluation

Abstract

Structural health monitoring (SHM) is a new technology that has been increasingly evaluated by the industry as a potential approach to improve the cost and ease of structural inspection. Piezoelectric smart active layer (SAL) sensor was fabricated to verify the applicability of finding cracks and conducting source location in a various materials. A crack detection and source location works were done in three kinds of test condition such as aluminum plates with crack for patch type SAL sensor, a smart airplane with embedding SAL sensor, and a concrete beam with real crack for practical application. From this experimental study, the evaluation algorithm for the arrival time delay and decrease of signal amplitude was suggested in this paper. Consequently, it was found that the SAL sensor and detection algorithm developed in this study can be effectively used to detect and monitor damages in the both existing structures and new designed smart structures.

Bending Strength of Al₂O₃ Ceramics for Textiles Machinery and Elastic Wave Characteristics by Wavelet Analysis

“…Thus, we used the wavelet transform (WT) scheme for analyzing the time response obtained by using resonant type AE sensors so the dominant frequency in the AE signal and its frequency analysis could be found. To apply this usefully to guarantee structural integrity and/or to the survey of destruction in structural engineering, the authors have already studied some items on several ceramics [7][8][9].…”