GROUND VIBRATION TEST (GVT) AND CORRELATION ANALYSIS OF AN AIRCRAFT STRUCTURE MODEL

Abstract– Ground Vibration Test (GVT) is one of the standard tests used for designing new aircraft. In this paper, GVT was carried out on an aircraft structure model by the phase separation method. In order to obtain more accurate results, the structure was excited by hammer, random and sine excitations. The results were then used to extract the modal parameters, i.e. natural frequencies, modal damping factors and mode shapes. Extraction algorithms were based on multidegree of freedom (MDoF) methods where several FRFs are analyzed simultaneously. Correlation between different test techniques was also investigated. Next, a finite element model of the structure was constructed and the theoretical modal analysis results have been compared with experimental ones. The test results obtained from the phase separation technique were also compared with a similar test carried out on the same structure by the phase resonance method. Finally, a cylindrical mass was added to the right tail wing of the model. A new set of modal tests was carried out to investigate the effect of unsymmetry on the modal properties of the structure.