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16.29: Determination of the residual stress distribution of steel bridge components by modelling the welding process
Author(s) -
Van Puymbroeck Evy,
Nagy Wim,
Schotte Ken,
UlAbdin Zain,
De Backer Hans
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.486
Subject(s) - welding , residual stress , materials science , heat flux , material flow , structural engineering , stress (linguistics) , thermal , finite element method , mechanics , mechanical engineering , composite material , heat transfer , engineering , thermodynamics , ecology , physics , biology , linguistics , philosophy
ABSTRACT Welding operations are typically used for the connections in steel bridges. Several locations with residual stress concentrations exist within the welded parts due to the welding itself, but also because of the influence of geometric discontinuities on the flow of the stresses. This can result in fatigue failure. The knowledge of residual stresses is essential to determine the effect of the residual stresses on the fatigue life behaviour of the welded components [1]. In this paper, the residual stresses of two flat plates of construction steel S235 welded together are determined by modelling the welding process. The temperatures during the welding operations are calculated in a thermal analysis, taking into account the thermal properties and behaviour of the steel. The heat input during welding is implemented on the model by defining a thermal flux for the different time steps representing the passage of the welding torch. A double ellipsoidal volume heat source is used to describe the heat flow through the material for a moving heat source. The distribution of the thermal flux is considered, taking into account the thermal material properties of steel as a function of temperature. After the calculation of the temperatures introduced during the welding process in the thermal analysis, a subsequent mechanical analysis is performed. The temperatures are introduced as a time dependent load onto the model. The elements of the model in the fusion zone of the welding are activated based on their reached temperature. The finite element modelling predicts the residual stresses induced by the welding procedure which can later be verified through comparison with measured residual stress distributions.