A correlation study of satellite finite element model for coupled load analysis using transmissibility with modified correlation measures

In this paper, a correlation study of satellite finite element (FE) models for coupled load analysis (CLA) using transmissibility and modified correlation measures is reported. CLA is performed with the launch-vehicle company to assess the structural integrity of satellite structure as well as the safety of its payload and electronics as a final verification by investigating the calculated acceleration, gap, and interface loads under launch environment conditions. To increase the accuracy of CLA, the complex FE model has to be validated via FE model updating with the results from dynamic tests, such as sine vibration testing, with proper criteria of correlation. When comparing modal properties obtained by analysis and testing, such as natural frequencies, mode shapes, and frequency response functions (FRFs), transmissibility measured from accelerometers with known input acceleration, but not input force, is used as a reference test data because it is often difficult or impossible to measure excitation force directly in many industrial structures.To match analysis results with the test results showing weak nonlinearity with respect to excitation level, several peaks of acceleration as well as modal properties are taken from transmissibility according to the excitation level, and then the FE model is updated using the sensitivity analysis with several correlation measures, such as frequency deviation error, frequency domain assurance criteria (FDAC), frequency response assurance criteria (FRAC) and modified versions of them to customize the correlation measures for CLA.Finally, it is shown that the proposed approach with transmissibility and the modified correlation measures is quite efficient and reliable for preparing a FE model for CLA, while meeting the standards of many aerospace agencies.