Développement d'une méthode de calcul des contraintes résiduelles pour la méthode des contours et mesures expérimentales des contraintes résiduelles de joints soudés en T sous l'influence de bridage

Abstract

This research involves two spécifie objectives. Initially, it is proposed to demonstrate the applicability of the constant pressure cell method (CPM), based on the influence functions established by Love from the Boussinesq and Cerruti équations for calculating residual stresses using the contour method. The motivations to use CPM instead of FEM are time savings and accuracy of solutions. To this end, an algorithm is developed and solutions are validated by means of finîtes cléments method (FEM). For comparable précision level, the CPM requires up to four fîmes less éléments than the MEF, and thereby, may proportîonally reduce Computing time. The second objective of the research program is to link the restraint intensity level of welded T joints with induced residual stresses. A séries of test is conducted. Each test is performed using a restraint device to obtain maximum rigidity. The restraint intensity is controlled by the plates thickness. In addition, the plates are instrumented with gauges and thermocouples throughout the welding process to collect déformation and température values inhérent to the process. The internai stresses are also studied through the contour method. The algorithm developed above is used. The displacement field is generated by an EDM eut at the center of each tested assembly. In addition, a new approach is proposed to calculate accurately the restraint intensity for T joints. This approach is determined from the dominant movements in the thermal shrinkage of the filler métal. The différent approaches of evaluating intensity are used to détermine the interaction between the clampîng intensity and the residual stress measured with strain gauges and calculated by the contours method in the T-joints.

Date	5 May 2010
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Raynald Guilbault (Supervisor)