Subspace Flexibility Identification Adaptive to Different Types of Input Forces

Impact testing is an effective means of identifying structural flexibility. However, most flexibility identification methods have strict requirements on the type of input forces. For instance, methods operated in the frequency domain may generate incorrect flexibility identification results when double or multiple clicks occur in an impact test. This article proposes a method to estimate the structural modal scaling coefficients and flexibility characteristics using a subspace identification algorithm in the time domain. The advantage of the proposed method is that it adapts to the input force type and thus has the potential to be widely used in engineering practice. Numerical and experimental examples are presented to illustrate the effectiveness and robustness of the proposed method.