Identification of steady-state uniform temperature distributions to facilitate a temperature driven method of Structural Health Monitoring

Structural Health Monitoring seeks to characterize the performance of a structure from combinations of recorded sensor data and analytic techniques. Temperature is normally considered noise in this analysis, obstructing the goal measuring the elastic response of the structure. While these elastic loads do help characterize a portion of structural behavior, the thermal loads on a structure can induce comparable strains to these elastic loads. Characterizing a relationship between the temperature of the structure and the resultant strain and displacement can provide a deep understanding of the structural condition. In order to begin characterizing this 3-dimensional relationship, time periods with relatively steadystate, uniform temperature distributions need to be identified from the measured data. These periods of uniform temperature distribution in the structure show a thermal response as free as possible from thermal gradients across the structure. These steady-state periods help create a signature of the structure when analyzed with the relevant strain and displacement measurements of the structure. An algorithm for finding these uniform distributions was created to identify these desirable time periods with data of interest. Finding time periods with a completely uniform temperature distribution can be unreasonable, so a suitable temperature interval was chosen to produce a set of data with a reasonable approximation to a uniform distribution, while still providing a large enough set of data to produce meaningful results. These time intervals provide the necessary temperature, strain, and displacement measurements to characterize a signature for the structure, providing a more in-depth analysis in SHM.