Finite element response sensitivity analysis in earthquake engineering

This paper presents a method to compute the exact sensitivities with respect to material constitutive parameters and discrete loading parameters of the computationally simulated response of a structure. Focus is placed on plasticity-based materially-nonlinear-only finite element models of structural systems and on two types of state-of-the-art analysis used in earthquake engineering, namely nonlinear static push-over analysis and nonlinear response history analysis. Implementation of the method in a general purpose nonlinear finite element analysis program (FEAP) is discussed. Application examples related to a concrete gravity dam and a moment-resisting building frame are provided, serving also to validate the exact response sensitivity results through their finite difference calculations. These application examples illustrate the fact that sensitivities with respect to both material and loading parameters of plasticity-based structural models are discontinuous in time and that the method presented is able to capture these discontinuities.