IMPROVED NUMERICAL INTEGRATION PROCEDURE FOR APPLICATION TO SEISMIC HYBRID SIMULATION

Hybrid simulation is a powerful test method for evaluating the seismic performance of structural systems.Thismethod makes it feasible that only critical components of structure be tested experimentally while the rest of the structure is numerically modelled. This paper presents a newly proposed integration algorithm for seismic hybrid simulation which is aimed to extend the capabilities of hybrid simulation to a wide range of systems where existing methods encounter some limitations. In the proposed methodwhich is termed Variable Time Step (VTS) integration method, an implicit scheme is employed for hybrid simulation by eliminating the iterative phase on experimental element, the phase which is necessary in regular implicit applications.In order to study the effectiveness of the VTS method, a series of numerical investigations are conducted, in them the restoring force of the column is assumed to be achieved experimentally. The results show the successfulness of VTS method in obtaining accurate, stable and converged responses.Also in a comparative approach, the improved accuracy of VTS method over commonly used integration methods isdemonstrated utilizing two error indicators.