Problemas termomecânicos inversos de processos de aquecimento localizado

Abstract

In the present work is presented a numerical methodology, based on finite elements, for the determination of the heat flux provided and the yield stress of the material of the structure with the temperature variation. To evaluate this methodology, experimental tests were performed on circular plates heated at the center by oxy-acetylene flame. Temperatures and displacements at different points of the plate are measured by means of thermocouples and LVDT’s, respectively. The heating model involves an uncoupled thermomechanical analysis using axisymmetric finite elements 2D. The Levenberg-Marquardt algorithm for the solution of the corresponding inverse problem, adapted for finite elements, was implemented to work together with the ANSYS commercial program. The development of the solution procedure involves comparing the temperatures and displacements measured in the experiment with those calculated in the numerical simulation of the process. In the thermal analysis, the heat flux supplied is discretized in blocks and compared to a Gaussian distribution. In the mechanical analysis, the yield stress varying with temperature is considered with multilinear behavior. The temperatures obtained numerically and the experimental ones present great approximation. Regarding the displacements, it can be said that for the regions farthest from the heat source, the numerical displacements show good agreement with the experimental ones.