Uncertainty quantification for nonlinear seismic analysis of cabinet facility in nuclear power plants

摘要

Effects of spatial variability of structural properties on seismic responses of cabinet facility in the nuclear power plant are investigated. For the nonlinear behaviour of the cabinet, the effects of the softening and axial force are investigated through the analytical model. The accuracy of the model is verified against the experimental tests. To account for the randomness of material and geometrical properties, input variables are treated as random variables and produced with the random field theory. An efficient method using the combination of a covariance matrix decomposition (i.e. Cholesky, Eigen, and modified Cholesky decompositions) and a midpoint discretization method is proposed and it is implemented for the stochastic response analyses of structures. The effectiveness of the method is evaluated with the dispersion and uncertainty of output responses. It is found that the heterogeneity of material properties has a strong influence on the seismic vulnerability assessment of cabinet facility, and the performance of modified Cholesky decomposition is better than other methods in generating random fields.