Advancement of Reference-free Diagnosis for Aging Aircraft Monitoring

摘要

The goal of this project was to develop a new NDT technique/algorithm based on Lamb waves, in which damage can be detected 'without relying on past reference data.' In particular, a NDT methodology was formulated for detecting defects such as crack, corrosion and delamination commonly found in aircraft. The proposed concept of 'reference-free' damage diagnosis attempts to address some of the fundamental technical hurdles that have to be overcome before NDT systems can be deployed for continuous monitoring of aircraft. The intent of the present approach is not to disregard useful prior knowledge or information gained but to relax explicit dependency on baseline data so that the proposed methodology can be made more attractive for aircraft monitoring during its normal operation. By incorporating the proposed approach to the conventional NDT techniques, it is envisioned that more reliable damage diagnosis can be achieved. New reference-free damage diagnosis techniques developed in this study are (1) Reference-free crack detection using transducer impedance: and (2) Instantaneous crack detection under varying temperature and static loading conditions.