This paper presents a system identification (SI) scheme in time domain using measured
acceleration data. The error function is defined as the time integral of the least square errors between
the measured acceleration and the calculated acceleration by a mathematical model. Damping
parameters as well as stiffness properties of a structure are considered as system parameters. The
structural damping is modeled by the Rayleigh damping. A new regularization function defined by
the L1-norm of the first derivative of system parameters with respect to time is proposed to alleviate
the ill-posed characteristics of inverse problems and to accommodate discontinuities of system
parameters in time. The time window concept is proposed to trace variation of system parameters in
time. Numerical simulation study is performed through a two-span continuous truss subject to
ground motion.
