A Multiphysical Modelling Approach for Virtual Shaker Testing Correlated with Experimental Test Results

A virtual shaker testing simulation environment aims to predict the outcome of a spacecraft vibration test numerically, prior to its physical execution at the environmental test facility. Therefore, it needs to comprise the complex dynamical characteristic of the test setup and facility in order to calculate and predict the interaction between the electrodynamic shaker system, test specimen, and vibration controller as it occurs during tests of large spacecraft. A currently derived one-dimensional multiphysical shaker model with three degrees-of-freedom, e.g. the 160 kN electrodynamic shaker of the European Space Agency (ESA), is based on a tailored experimental system identification methodology to estimate the system's parameter. The model is validated by subsequent simulations to recalculate and predict the test results. The main focus of the paper is the enhancement of the shaker model to encompass additionally, lateral and rotational dynamics of the shaker table as well as the coupling with test specimen dynamics and control system performance. The improvements are based on analytical modelling steps in conjunction with the exploitation of experimental test results of hammer impact excitations, and closed-loop random and sine control testing performed on the shaker, loaded with a dummy specimen and excited with different excitation levels.