Piezoelectric Transponder System for Naval Aircraft Damage Detection

A structural health monitoring system is proposed for Naval aircraft such as the V22. Changes in measured dynamic properties will be the basis for detection of problems. The key innovation is the use of piezoelectric transponder patches to perform both actuation and sensing. Advantages include (1) identical conditions for every test repetition in terms of location and orientation of actuation and sensing, (2) ability of each patch to induce strain over an area many times its own size, and (3) excitation in a medium frequency range, avoiding both low-frequency modes that are sensitive to changing store weights and high frequency dynamics that cannot be characterized by normal modes. Damage detection will be sought by comparison of frequency response functions measured on the aircraft early in its life to those measured periodically thereafter. Phase I efforts will consist of finite element simulations and bench-scale experiments using prototype piezoelectric patches on a test article of aircraft-like construction. Automated means for signature comparison and correlation with damage will be sought. The proposed system will be especially beneficial for composite structures, but should also be useful for metallic structures.