Interaction of Lamb Waves with Fatigue Cracks in Aluminum
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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Elastic waves can travel across relatively large distances in thin metallic plates, and can be affected by discontinuities such as cracks. This paper presents an investigation of the interaction of Lamb waves with both open and closed low-cycle fatigue cracks in aluminum plates using a three-dimensional laser Doppler vibrometer 3D-LDV. The 3D-LDV provides measurements of both in- and out-of-plane velocity components over a uniform grid of up to 27,000 points with approximately 0.7 mm spacing in the x- and y-directions. Images created from the 3D-LDV measurements clearly show the interaction of the elastic wave energy with the cracks. Comparisons between in- and out-of-plane components provide insight into whether and how the propagation behaviors of symmetric and antisymmetric Lamb wave modes differ upon encountering fatigue cracks.
- Properties of Metals and Alloys
- Acoustic Detection and Detectors