1. 南京航空航天大学,飞行器结构力学与控制教育部重点实验室, 南京210016；2. Dynamics Research Group, Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD，England
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
1. Key Lab of Structure Mechanics and Control for Aircraft (Ministry of Education), Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China 2. Dynamics Research Group, Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD, England
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.
2012, Vol. 31 
