Dynamics-based Damage Inspection of an Aircraft Wing Panel

Abstract

This paper presents damage detection of an aircraft wing panel using dynamic responses. The panel has an irregular shape, varying thickness, seven ribs on its backside, and defects. An in-house finite element code GESA (Geometrically Exact Structural Analysis) was used to model the panel using 528 DKT plate elements and to obtain mode shapes and natural frequencies, and experimental dynamic characteristics and Operational Deflection Shapes (ODSs) were measured using a scanning laser vibrometer. Results show that numerical dynamic characteristics agree well with experimental ones. Six defects were created in the panel, including four small nuts glued on the backside and two small slots cut by electron discharge machining. Detection of the six defects was performed using the distributions of RMS velocities under high-frequency broadband periodic chirp excitations provided by a PZT patch and damage locating curves obtained by processing experimental ODSs using a newly developed Boundary Effect Evaluation (BEE) method. The BEE method is nondestructive and model-independent; it processes experimental ODSs to reveal local boundary effects caused by defects. Experimental results show that the six small defects in the panel can be pinpointed using the approach.