Abstract：In order to increase usable testing information in each dynamic testing, a dynamic response expansion method was proposed for spatial trusses under step excitations. The structural free vibration responses at any time which are caused by step excitations can be approximated by linearly combining several contribution modes. Based on the approximate expression of dynamic responses, an iterative strategy was put forward to select optimal tested locations, aiming to obtain unbiased estimates of contribution mode coefficients (i.e., generalized coordinates) at each moment. The dynamic response expansion was then naturally realized from only a few tested locations to the full degrees of freedom. The dynamic response expansion mechanism was explained, and a correlation coefficient index was established to select non-tested locations with high expansion accuracy. A spatial truss with 560 members was numerically studied. Results show that the proposed method can conveniently accomplish the dynamic response expansion for the spatial truss, select many non-tested locations with high expansion accuracy, and is beneficial to improve the efficiency of the dynamic testing of spatial trusses.
Key words: spatial structures; dynamic testing; response reconstruction; model updating; step excitation.
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WU Xiaoshun, CHENG Runhui. Dynamic response expansion and its error analysis of space truss structures under step excitation. JOURNAL OF VIBRATION AND SHOCK, 2022, 41(17): 213-220.
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