Stochastic response analysis of 3D vibro-acoustic system with acoustic impedance and modeling parameter uncertainties

A novel stochastic response analysis scheme for 3D vibro-acoustic systems is constructed based on the PUFEM/FEM and the direct probability integral method, and the effect of uncertain acoustic impedance and modeling parameters on the system response is investigated. The proposed scheme has the capability of capturing waveform within the element, the small system matrices and easy handling acoustic impedance, also can efficiently treat the propagation of parameter uncertainties through transforming the integration of the response probability density function into the summation of the response under each representative point by partitioning the input probability space and smoothing the Dirac & delta; function. Numerical examples show that the mean and standard deviation of the responses computed by the proposed scheme agree well with the MCS, but the agreement of the standard deviation is slightly lower at the frequency with large response dispersion. The effect of uncertain acoustic impedance on the system response is mainly at the low frequencies, where the location and amplitude of resonance peaks fluctuate significantly. Uncertain modeling parameters synthetically modify the stiffness and mass matrix, altering the intrinsic properties and response of the system, and the response at the higher frequency is more sensitive to the uncertain modeling parameters.