Identification of nonlinear structural dynamic systems using wavelets

This paper addresses the use of wavelets in the identification of nonlinear structural dynamic systems. The proposed method accurately determines hysteresis curves and damping coefficients of the structural system without the need for prior assumptions about the nonlinear characteristics of the system, thereby enabling us to clarify complex phenomena occurring in nonlinear behavior. The tangent stiffness of the structural system is expressed as a series expansion of wavelets. The coefficients of the series are estimated by means of the least-squares method. This identification method has been applied to numerical and experimental results under earthquake motion, demonstrating its effectiveness and applicability.