Stress And Damage Sensing Of Composite Coupons With Piezospectroscopic Coatings

The application of piezospectroscopy (PS) as a technique for evaluating stress and predicting life of turbine blade coatings has been expanded through the development of an alumina-epoxy nanocomposite coating that can be applied to a wide array of structures. This work continues the development of PS coatings for structural health monitoring with novel experimental testing. The PS coating was applied to an open hole composite coupon under tensile loading and tested in conjunction with digital image correlation. The digital image correlation provided a secondary strain measurement. The PS measurements revealed spatial patterns that were comparable to strain field measurements using digital image correlation. A phenomenon described as a PS drop is proposed to be a quantifiable value that is related with loss of structural integrity and material state. Additionally, the data was collected over a field of view that allows for the estimation of the size of the damaged area. Copyright 2014 by University of Central Florida and Boeing Research & Technology