Proceedings home preface contents authors keywords copyright reference ©2012 Civil-Comp Ltd				Paper 297 A Practical Tool for Estimating Errors of Stresses in Assemblies S. Pavot1, E. Florentin1, P. Pasquet2 and S. Guinard3 1LMT-Cachan (ENS Cachan / CNRS / UPMC / PRES UniverSud Paris), France 2SAMTECH, Massy, France 3EADS-IW, Toulouse, France Keywords: assemblies, error estimation, quantity of interest. full paper (pdf) - reference A common practice in the framework of industrial design is to use finite element codes to model assemblies. In this paper a study is presented examines the quality of such simulations. Some work has been developed in the past for controlling finite element simulations with contact but the measure introduced was global. Mechanical criteria are often local, hence a global measure is not sufficient. The path followed is to obtain an error in a quantity of interest and to extend previous work developed for linear analysis. The final objective is to control meshing in the framework of assemblies, starting from the local error measure defined in this work. For more than thirty years the global discretization error has been extensively developed. More recently, research has focused on goal-oriented error estimation, i.e. the estimation of the error on specific outputs of interest, which may be relevant for design purposes. Several techniques have been proposed for goal-oriented error estimation, and particularly for linear problems based on the resolution of a dual problem. Extensions of this method have also been proposed for different non-linear problems. Here a different approach is proposed that results in a lower cost. The results are not proved mathematically but remains very sharp, which is interesting from a practical point of view. Here the constitutive error concept is used to estimate the finite element error. This method relies on the construction of the so-called admissible fields. The first point of the work, described in this paper, is to revisit the construction of the stresses that check equilibrium. Particular attention is paid to the construction at the boundary of the studied domain; especially for boundaries that are part of the contact zone. From a practical point of view, some information can be missing as a result of file transfer between the codes and are not available for a posteriori error estimation. The second point is to develope a practical tool for estimating error on the bais of stress. Different methods are proposed and numerical tests are carried out in order to illustrate the proposed methodology.