Study of the approximate approaches to the POD based spectral representation method

The spectral representation method (SRM) is most widely used in simulating the stochastic field. The proper orthogonal decomposition (POD) based SRM is an important form. This paper investigates the approximate approaches to the POD-based SRM in simulating two typical problems, i.e., the seismic ground motion and wind velocity fields simulations. Then, the accuracy resulting from the power spectral density matrix-based POD method (PSRM) is compared to that of the coherency matrix-based POD method (CPSRM). It is concluded that the CPSRM maintains a much higher accuracy than the PSRM. In the CPSRM, the linear interpolation of eigenvectors and third-order polynomial interpolation of eigenvalues can be accepted to attain high accuracy; the linearly distributed interpolation nodes are effective in the ground motions simulation; however, the exponentially distributed interpolation nodes are effective in the wind velocity simulation.