Spacecraft base-sine vibration test data uncertainties investigation based on stochastic scatter approach

This article describes some results of the study “DYNAMITED”. The study is funded by the European Space Agency (ESA) and performed by a consortium of European industries and university, led by EADS Astrium Satellites.One of the main objectives of the study is to assess and quantify the uncertainty in the spacecraft sine vibration test data. For a number of reasons as for example robustness and confidence in the notching of the input spectra and validation of the finite element model, it is important to study the effect of the sources of uncertainty on the test data including the frequency response functions and the modal parameters.In particular the paper provides an overview on the estimation of the scatter on the spacecraft dynamic response due to identified sources of test uncertainties and the calculation of a “notched” sine test input spectrum based on a stochastic methodology.By means of Monte Carlo simulation, a stochastic cloud of the output of interest can be generated and this provides an estimate of the global error on the test results. The cloud is generated by characterizing the assumed sources of test uncertainties by parameters of the structure finite element model and by quantifying the scatter of the parameters. The uncertain parameters are the input random variables of the Monte Carlo simulation.Some results on the application of the methods to telecom spacecraft sine vibration tests are illustrated.

► Assessment and quantification of a wide variety of uncertainties in mechanical testing.
► Estimation of the scatter on the spacecraft dynamic response due to identified sources of test uncertainties.
► Calculation of a “notched” sine test input spectrum based on a stochastic methodology.