Use of DSA analysis results for Ritz fast analysis of perturbed models

Finite element analysts often have to perform analysis of perturbed models in order to validate the dimensioning through sensitivity analysis. This is also the case during Finite Element model updating process or for stochastic dynamic analysis where we want to obtain a statistical description of a solution, provided the statistical distributions of some design driving physical parameters. These analyses often lead to a huge amount of calculations if the analysis is performed using a loop inside a Finite Element software. CNES has developed a fast dynamic reanalysis method based on a Ritz formulation using the results of a Design Sensitivity Analysis performed with MSC/NASTRAN in order to introduce the variation of some physical parameters in the analysis. This paper presents the basic developments and implementation of this method.