COMPOSITE AEROSPACE STRUCTURE IN-SITU DIAGNOSTICS WITH THE USE OF NETWORK PZT SENSORS

In the article, an approach for damage characterization in composite aerospace structures for the linear acoustic non destructive evaluation technique is presented. The damages which affect the structural integrity of such components among others are: disbonds, delaminations and foreign object inclusions. One of the significant damages which may occur during structure operation is low energy impact damage (BVID - Barely Visible Impact Damage). BVID may decrease the stiffness of the component due to the creation of internal damages resulting in impact energy dissipation across the material. In the paper an approach for their diagnostics is presented. The approach is based on structure integrated PZT piezoelectric sensors. The application of such sensors enables acoustic and local distortion fields propagation based on the physics of small displacements in continuous media. This can be affected by local geometry changes caused by BVID which opens an opportunity for their detection. The signal processing methods which may enable damage detection and their classification are presented in the article. The results of low energy impact detection based on the PZT sensor network approach as well as their full characterization using classical NDE are also provided.