An advanced Acoustic Emission (AE) monitoring and signal processing system was developed and applied to elucidate the fracture dynamics of hydrogen assisted cracking (HAC) of QT-treated low alloy steel. The developed system enables to monitor an initiation of microcrack correctly and also to elucidate the dynamics of microcracks when multi channel moment tensor analysis is jointly used. The system consists of 8 channel monitoring. One channel monitors the surface displacement in loading direction excited by the propagation of elastic wave, and gives the source wave by the deconvolution integral of it with the Green’s function of the second kind. Another 7 channels were designed to measure arrival time and relative amplitude of the P-waves, and to determine both the source location and the crack kinematics by tensor analysis. This paper introduces the developed monitoring system and signal processing method, and fracture dynamics of microcracks in HAC.

Subject
Openings, Sensors, Geometry, Microcracks, Notches, Crack initiation, Crack propagation, Waves, Stress cracking, Fracture, Cracks, Hydrogen, Low alloy steel
Keywords:
Acoustic Emission, Hydrogen Assisted Cracking, Moment Tensor, Fracture Dynamics, Green’s Function, Inversion Processing
© 1994 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1994
Association for Materials Protection and Performance (AMPP)
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