TIME-DOMAIN PARAMETER-ESTIMATION ALGORITHM FOR STRUCTURES .1. COMPUTATIONAL ASPECTS

A time-domain equation error estimator is proposed for the problem of estimating constitutive parameters of a complex linear structure. We h ave assumed that the geometry and topology of the model are known and have measured the history of applied loads, and the accelerations at c ertain locations. For the proposed parameter estimation algorithm, we first estimate the displacement and velocity at the locations where ac celerations have been measured by standard integration/filtering techn iques. We recast the equations of motion as a discrete multistep metho d in terms of the displacements at the unmeasured degrees of freedom, and establish our measure of error as the weighted sum of residual for ces at adjacent time points. We estimate the unknown constitutive para meters by solving a constrained nonlinear optimization problem, and ta ke the parameter estimate to be the average of estimates over several time windows. We advocate the use of the recursive quadratic programmi ng method to solve the optimization problem. The proposed time-domain estimator can accommodate response sampled incompletely in time, state , and space and is amenable to identification of complex structural sy stems.