Real-time hybrid testing of a structure with a piezoelectric friction controllable mass damper by using a shake table

A structure with semi-active control devices is usually a highly nonlinear system. To investigate the aseismic performance of such a system, real-time hybrid testing (RTHT) can be a cost-effective experimental method. However, a substructure with a semi-active friction device is difficult to be tested by the RTHT, because the dynamic behavior of a friction device, which consists of sliding and sticking phases, is determined by the exerted force of the primary structure, rather than its displacement response. To overcome this problem, a methodology of RTHT with a shake table (RTHT-ST) is utilized in this study. In the RTHT-ST, which is an experimental technique combining shaking table test and RTHT, the shake table is employed to mimic the acceleration response of the primary structure that is simulated by a numerical model and imposed to the substructure, which is mounted on the shake table. In order to verify the feasibility of the experimental method, a semi-active piezoelectric friction controllable mass damper substructure is tested by using the RTHT-ST. The test results of the RTHT-ST are compared with those of a full shaking table test, in which the integrated primary structure and piezoelectric friction controllable mass damper system have been physically tested. Moreover, to evaluate the accuracy of the RTHT-ST result, one category of indicators called root-mean-square energy error index is also proposed. Unlike previously existing hybrid-testing indices, the root-mean-square energy error index is able to distinguish modeling error from control system error.