Euclid Spacecraft Sine Vibration Test Prediction Through the Virtual Shaker Testing Technique

In the space industry, the sine vibration test prediction of a spacecraft is approached numerically by exploiting the spacecraft finite element model (FEM). A frequency response analysis is run for this purpose, and the spacecraft is assumed in hard-mounted boundary conditions, thus neglecting the shaker compliance. Consequently, unrepresentative structural predictions may lead to test article under- or overtesting, as well as incorrect FEM mathematical model updating, and affect the proper fulfilment of the launcher frequency requirements. Virtual shaker testing (VST) solves these issues by including the shaker FEM within the computational framework and exploiting a coupled transient analysis inclusive of the vibration control system. In this study, VST is applied as a pioneering predictive tool to study spacecraft-shaker dynamic coupling of the Euclid spacecraft, before mechanical qualification tests. Experimental measurements such as test control accelerations, lateral bending moments, cross talk, and notching were effectively predicted and compared to the classical approach. Compression factor effects were investigated through a sensitivity analysis, and test predictions were strongly influenced by this parameter. VST has been shown to be a valid methodology to faithfully simulate the sinusoidal test and extract data otherwise unavailable.