Modal analysis based on power spectral density data
Heung‐Fai Lam, Jia-Hua Yang · 2022
This chapter discusses a practical method using power spectral density (PSD) data for modal analysis of full-scale structures without measuring excitations. The PSD around a spectral peak is first modeled using modal parameters. The modal parameters are identified by minimizing the difference between the experimental and model-predicted PSDs. Optima of mode shapes and PSDs of modal excitations given other modal parameters are analytically derived to reduce the dimension of minimization. Based on these optima, an efficient minimization algorithm is developed by iterating among modal parameters. A numerical study and an experimental study of a full-scale structure are used to demonstrate the proposed method.