Comparison of modal parameter estimation techniques on aircraft structural data

Abstract

Five global time domain parameter estimation methods, least squares, double least squares, total least squares, correlation fit and Smith least squares were compared using the same set of impulse responses taken from the ground vibration test of an aircraft structure. The behaviour of the modal parameter estimates was investigated for changes in the solution order and number of data points analysed. The techniques produced comparable results for the dominant modes, although there were some differences in the estimates of the other modes. The correlation fit and Smith least squares approaches found equivalent estimates to the other methods while using much smaller computational model orders.