Inelastic Dynamic Response of Structures Using Force Analogy Method

A new algorithm based on the force analogy method for studying the inelastic structural behaviors subjected to dynamic loadings is proposed. Inelastic analysis is performed based on varying the structural displacement field, which differs from the conventional method of changing stiffness. Each inelastic deformation of the structure is denoted as a degree of freedom, and therefore all inelastic behaviors are represented by a single equation. The algorithm is very time efficient because only initial stiffness is used, and it achieves high numerical accuracy when incorporating the use of a state space numerical integration method in dynamic analysis. Moreover, this algorithm is dynamically stable in analyzing structures with not only strain-hardening properties, but also elastic-plastic properties and strain-softening properties. Comparison between the proposed algorithm and an existing inelastic dynamic analysis software program is performed to demonstrate the accuracy and efficiency of this algorithm. Finally, application of the proposed algorithm to the dynamic response of a six-story hospital building is presented to show the complete inelastic analysis procedure in analyzing realistic structures.