Instantaneous frequencies identification for linear time-varying structures using continuous wavelet transform of free decay acceleration response

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Journal of Vibration and Shock ›› 2012, Vol. 31 ›› Issue (20) : 166-171.

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Instantaneous frequencies identification for linear time-varying structures using continuous wavelet transform of free decay acceleration response

XU Xin1, 2, SHI Zhi-yu1, Wieslaw J. Staszewski 2, Long Shuang-li1

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Abstract

This paper presents a deduction on continuous wavelet transform of an arbitrarily function’s integration. Based on this algorithm, assuming the linear time-varying structural mass coefficients are constants or known in advance, the CWT values of the velocities and displacements response of a linear time-varying structure can be estimated only by using free decay acceleration response. Consequently the time dependent physical parameters (stiffness and damping) at different instance can be determined by solving least square problem from simple linear equations of a short time. Subsequently a five-story shear-beam building model and a three degree-of-freedom structure with closely spaced modes are investigated and their instantaneous frequencies are identified by the proposed method. Numerical results validate the proposed identification method with good accuracy, effectiveness and improved anti-noise capability.

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time-varying system / parameter identification / continuous wavelet transform / acceleration response

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XU Xin;;SHI Zhi-yu;Wieslaw J. Staszewski;Long Shuang-li. Instantaneous frequencies identification for linear time-varying structures using continuous wavelet transform of free decay acceleration response[J]. Journal of Vibration and Shock, 2012, 31(20): 166-171