Patent ID: 8892384
Filing Date: 2014-11-18
Classification: G01M,G01N

Abstract:
1. A method for compensating for environment induced variations in structural health monitoring application data, said method comprising: imparting a vibration signal onto a structure at a first location, the structure at a first temperature; receiving a comparison signal at a second location of the structure, the comparison signal resulting from the vibration signal; accessing data representing a reference signal, the reference signal previously received at the second location, based on an imparted vibration at the first location, the reference signal received when the structure was at a second temperature; dividing the comparison signal and the reference signal across a plurality of time windows; performing a cross correlation between the comparison signal and the reference signal in each time window by recording an amount of time shift required to maximally correlate the comparison signal and the reference signal within each time window; performing a weighted regression on time to estimate time delay, the weights based on a relative amount of signal energy from the reference signal in each time window, to determine a relationship between time and time shift as a quadratic or higher order equation, wherein a weight for higher signal energy in each time window is greater than a weight for lower signal energy in each time window; and using the determined relationship between time and time shift of the comparison signal to reduce the effects of environment on the comparison signal.