Publications Details

Estimating the uncertainty in modal parameters using SMAC

Simmermacher, Todd W.; Mayes, R.L.

Estimation of the uncertainty in experimental modal parameters is valuable when validation of a finite element model is performed based on modal frequencies and shapes. The uncertainty in the data is needed to establish distribution functions for the comparison to computational models. A part that is typically neglected with the experimental data is to quantify the uncertainty in the estimated parameters established from the data. This uncertainty is an important piece of the puzzle in a validation exercise. If the uncertainty in the fit is not accounted for, the uncertainty estimate of the experimental data is incomplete. This paper will explore the uncertainty of the modal parameter estimates measured from the Synthesize Modes and Correlate (SMAC) algorithm using a Monte Carlo technique. The uncertainty in the parameter fit will be determined for both analytically and experimentally determined frequency response functions. It is found that the largest uncertainty in the SMAC algorithm is within the optimization step of the fitting process. © 2009 Society for Experimental Mechanics Inc.