Element level structural damage detection with unknown excitation

摘要

A finite-element based time domain system identification algorithm is proposed to identify the element parameters of structures subject to some unknown(unmeasured)excitation inputs.In the algorithm,only limited numbers of acceleration measurements of structures are utilized.Structure state vectors are treated as implicit functions of structural dynamic parameters and excitations.The unknown structural dynamic parameters and excitation inputs are identified by an algorithm based on recursive least squares estimation with unknown excitations(RLSE-UI).Structural damage at element level is detected by the degrading of stiffness of damaged structural elements.Numerical simulation results of a three-story plan shear building with proportional damping and a one-story plane steel frame structure with Rayleigh damping demonstrate that the proposed algorithm can identify structural element stiffness parameters and detect structural damage at element level with good accuracy.