A receptance based formulation for modal scaling using mass perturbations

Normalization of modes obtained from operational modal analysis has received significant attention since the seminal paper on the use of mass perturbations by Parloo et al., in 2002. The contribution in this paper is a formulation where the square of the scaling constants are computed from an over-determined linear system of equations, obtained by evaluating the pole residue form of the receptance at the eigenvalues of the perturbed system. The formulation is exact when there is no truncation and, independently of truncation, for all conditions where existing solutions are exact. Given that identification results are stochastic, the normalization constants are random variables and the paper examines performance in terms of the bias and the standard deviation of the error distribution. The advantage of the receptance approach over other existing techniques is illustrated.