Assessment of damage detection methods in GRID-LOCK® structures

Bonded metallic GRID-LOCK® structures are being adopted for a variety of aerospace applications due to their structural efficiency and damage tolerance. However, effective damage detection in these structures is complicated by a lack of interior access. In this paper, the feasibility of various non-destructive evaluation (NDE) techniques for detecting the presence, location, and magnitude of damage in GRID-LOCK® is investigated. Experiments conducted on a GRID-LOCK® test structure reveal that vibration-based damage detection and optical nde methods are superior to ultrasonic C-scans in detecting disbond defects. Finite-element analysis (FEA) is used to interpret experimental results and highlight the advantages of alternate NDE approaches.