128 C. Beale et al. Fig. 11.24 TRAC values of all nodes computed from the expanded time responses for all expansion approaches and test cases generally yielded an inverted matrix having a condition number within the range of 3–25. The only case that yielded a higher condition number was during the mode shape expansion analysis for the lowest noise severity. This is likely because the noise was too insignificant to have a notable effect, as explained by the good correlations that were achieved without regularization using an inverted matrix with a condition number of ~487. The expanded results obtained using regularization were significant but were not enough to yield good correlations for the shapes of all modes and time responses of all nodes. In the most severe noise cases for both expansion types, several diagonal MAC values and numerous TRAC values were low (below 0.9). Therefore, it is important to note that regularization can provide considerable improvements to the results but cannot completely resolve the issue of noise contamination in the expansion process. The data should be thoroughly assessed and appropriate engineering judgement should be used before deciding to apply regularization, and expansion in general, on noise contaminated data.
RkJQdWJsaXNoZXIy MTMzNzEzMQ==