Identification of Materials Properties by Thermo- Mechanical Tests Results

This paper deals with the problem of identifying material parameters by means of measured mechanical and/or thermal quantities. We propose different energy functions measuring the distance between Analysis and Tests. They allow to compute indicators which determine if a given set of experimentally obtained data is able to identify the desired thermal and/or mechanical material characteristics. These indicators are based on error measures on the constitutive relations. The so-called constitutive relations relate the load quantities (ie stress, heat flux vector) to the strain and/or temperature. These indicators measure the potentiel validity of the identification method in evaluating material parameters. The same functionnals in which the correction variables are introduced, are used also to update the tensors associated with the material properties. I) Introduction The identification of structural parameters commonly uses a function describing the difference between the predicted results given by a parametric modeling and the experimentally obtained data. For complex structure The modeling, most often is a finite element model. It is described with initial values of structural parameters. These parameters should be corrected minimizing the gap distance between Analysis and Tests. Several methods have been developed for updating problems and can be found in the literature, [see for example the Friswell and Motterheads review paper in [1], Gladwell in [2]]. Most methods are dedicated to mechanics and concern dynamic test data. Identification techniques in thermal engineering are well developed [3] [4]. Here we look for an unified approach allowing to conjugate thermo-mechanical data to improve the identification of material characteristics.