Patent ID: 8232801
Filing Date: 2012-07-31
Classification: G01R

Abstract:
1. A method of monitoring stress in a composite, comprising: scanning the composite using an NQR spectrometer, the composite comprising a polymer matrix and a microcrystalline material disposed in the polymer matrix, wherein the microcrystalline material comprises molecules having nuclei with respective nuclear quadrupole moments; correlating using the NQR spectrometer, one or more locations of the composite with NQR spectra collected at the one or more locations to produce localized NQR spectra; generating using the NQR spectrometer, an average local strain map of at least a portion of the composite from the NQR scan; comparing using the NQR spectrometer, the generated average local strain map to an original strain map of the composite; and determining using the NQR spectrometer, differences between the generated average local strain map and the original strain map based on the comparison of local strain data contained within each map to quantify fatigue in the composite.