Load Updating for Finite Element Models

Abstract

A method for reducing the differences between experimental testing or real-world events and their finite element counterparts is presented. In this method system identification or finite element model updating are not performed; instead, the loads on the finite element model that would create equivaient displacements or strains are identified by various means, thus saving a large amount of computational effort. This method of finding an applied load is also extremely useful in the analysis of testing data for vehicles and other structures. Using methods based on classical least-squares methods, we present the basis for finite element load updating and sample application through the use of a computer program for a beam under static loads. We examine the conditioning number of the resulting system of equations and provide a least-squares solution that is more robust through the use of singular value decomposition. This allows an easier analysis of structural models, for example, of a prototype vehicle, by determining the loads that the prototype is subjected to in testing. These loads can then be used on other models of that vehicle during the design process to decrease the time spent in testing while increasing design's reliability by reducing uncertainties in the applied load.