Inelastic dynamic response of structures using force analogy method

A new algorithm based on the force analogy method for studying the inelasti c 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 inel astic deformation of the structure is denoted as a degree of freedom, and t herefore all inelastic behaviors are represented by a single equation. The algorithm is very time efficient because only initial stiffness is used, an d it achieves high numerical accuracy when incorporating the use of a state space numerical integration method in dynamic analysis. Moreover, this alg orithm is dynamically stable in analyzing structures with not only strain-h ardening properties, but also elastic-plastic properties and strain-softeni ng properties. Comparison between the proposed algorithm and an existing in elastic dynamic analysis software prog;ram is performed to demonstrate the accuracy and efficiency of this algorithm. Finally, application of the prop osed algorithm to the dynamic response of a six-story hospital building is presented to show the complete inelastic analysis procedure in analyzing re alistic structures.