Fluctuation of Structural Response, Why and How

The uncertainties involved in a structural system are discussed in conjunction with the resultant fluctuation of structural response. The methodology studied is a stochastic finite element method which is based on the mean-centered second order perturbation technique. Small probabilistic variables are assigned to finite elements in order to represent the uncertainties, and the rates of change of the finite element solution with respect to the probabilistic variables are evaluated by means of the perturbation technique. A way is described to estimate the variance of structural response in relation to the variance of the uncertainties. Numerical examples are given in regard to inply stresses of an FRP laminated plate with uncertain stacking parameters and natural frequencies of spatial pipe whose restraint locations are uncertain.