Extraction of Modal Parameters from Structural Acoustical Responses

A method to identify modal parameters from structural acoustical signals was proposed by a combination of empirical model decomposition (EMD) and stochastic subspace identification (SSI). Firstly, several intrinsic mode functions (IMF) were obtained with EMD, then the data obtained from the EMD was used as the input of the SSI to identify the modal parameters. Taking a wheel loader as an example, the acoustical signals in the loader cab were recorded through field tests, and were employed to identify the fundamental modal frequencies. The resultant frequencies show reasonable consistency with those by finite element analysis, and therefore prove the feasibility of the proposed method, which means that acoustical signals could be utilized as a useful supplement of the structural vibration responses in the modal parameter identification.