Comparative results for DSS and hybrid testing for a base isolated structure with rubber bearings

In a general sense, there are two main types of method for dynamical substructuring testing. One is the hybrid test method, which is the most well-known and commonly used for pseudo-dynamical substructuring tests. The other is the dynamical substructuring system (DSS) method, which has been developed and proposed relatively recently. These approaches differ in the method of analysis and control synthesis and therefore in the manner of determining input signals to the test rig actuators. In hybrid testing the outputs of the numerical substructures are fed directly into the physical substructures via actuators, under the idealized assumption that such boundary output/input pairs are identical. In contrast, DSS is based on a control synchronization approach, which is synthesized to ensure that the boundary errors between the numerical and physical substructure outputs are driven towards zero, via the action of the actuators. Although the difference in the two methods is known, the comparative performance of the methods has not yet been studied in dynamical substructuring tests. Therefore, this paper compares the performance of these methods via dynamical substructuring tests for base isolated structures with natural rubber bearings. Dynamical substructuring tests with the hybrid test and DSS were conducted for an experimental system having a pure time delay 6.0ms, itself resulting from a series of digital processing delays. DSS achieved the dynamical substructuring test goals whilst maintaining stability, whereas the hybrid test failed to do so. DSS was found to maintain stability with a pure time delay of up to 19.0ms.