Implementation of Effective Force Testing for Nonlinear Structures

Abstract

Effective force testing (EFT) is a dynamic testing method that can consider the rate-dependent behavior of a structure. Because of the lack of knowledge of real-time force control for a servohydraulic actuator, however, EFT has seldom been used within the testing community. Recent advances in force control enable the force application to nonlinear structures in real-time and effectively resolve the natural velocity feedback issue of servohydraulic actuators. With the aid of the new real-time force control method, this paper demonstrates EFT conducted for a small-scale nonlinear concrete mass block system combined with a rubber bearing and a frictional slider, which was a challenging task to implement with the previous knowledge of EFT. This study uses two different earthquake ground motions with different frequency contents for the EFT. The accuracy of the applied effective force is evaluated by comparing the time domain data and the response spectra. In addition, a nonlinear numerical model for the test structure is constructed and used for numerical simulation to compare its result with the EFT result. Overall, satisfactory results are obtained, which show that this study successfully conducted the EFT.