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- Edstorp, Marcus, 1980-
(författare)
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A Simplifed Finite Element Formulation for Spray Transfer GMA Weld Pools
- 2008
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Ingår i: Progress in Industrial Mathematics at ECMI 2006. - Berlin, Heidelberg : Springer. - 9783540719915 ; , s. 822-826
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Konferensbidrag (refereegranskat)abstract
- This chapter is concerned with the matter of mathematically modelling and computationally simulating the thermo and fluid dynamical phenomena occuring in the workpiece during a gas metal arc welding (GMAW) process, and does so by employing a continuum mechanical approach and a finite element formulation for approximating the solution of equations expressing the continuity of mass, the balance of linear momentum, the conservation of energy and the motion of the weld pool surface. GMAW is an electrode arc fusion welding process. The designation arc fusion signifies that an electric arc is struck between the welding electrode and the workpiece, and this causes the base material to melt on either side of the joint. During the subsequent solidification this will cause fusion between the workpiece parts. The electrode consist in a filler metal, and it is hence consumed during the process and molten droplets are, under the influence of electromagnetical and gravitational forces, transferred to the liquid weld pool. Mass is thus added to the workpiece and this causes a reinforcement of the joint.
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- Edstorp, Marcus, 1980-
(författare)
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An Investigation of Mesh Moving Methods for Simulating the Deformation of Incompressible Fluid Bodies
- 2009
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Ingår i: COMSOL Conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this article we apply a finite element method for approximating the geometrical deformation of a two dimensional incompressible fluid body the flow velocity of which is not constrained along its top boundary. As a pressure force is applied on the free boundary, the domain occupied by the fluid deforms. There are several well established methods for treating this type of problem. The purpose of the present work is to investigate the computational efficiency of a number domain-mapping methods, which are akin to many solid mechanical applications involving large deformations, in that they employ a mapping of the initial configuration range onto the current. However, in fluid dynamical applications the deformation of the fluid body may be very large and contain several vortices. When employing domain-mapping methods, the spatial representations of the element domains are attached to the motion, and the Lagrange formulation is therefore inadequate. Instead we wish to find a motion which minimizes the element deformations and the computational complexity of the problem, while satisfying the kinematic constraint along the boundaries.
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- Edstorp, Marcus, 1980-
(författare)
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Weld Pool Simulations
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This investigation is devoted to the study of welding and its effect on the workpiece, focusing on the thermo and fluid dynamical phenomena occuring during a autogenous or nonautogenous arc fusion welding process. Its aim is to simulate the behaviour of the weld pool and analyze the consequence of the solid-liquid phase change, thus obtaining a methodology for predicting the appearance of weld defects related to solidification and cooling. In order to accomplish this, we solve equations governing a number of continuum mechanical and electromagnetical quantities, as well as consider the motion of the freely moving boundary of the weld pool. Since the state of these quantities is strongly influenced by phenomena such as arc and droplet impingement, non-isothermal phase change, surface tension, Marangoni forces and Lorentz forces, much effort is necessarily devoted to the modelling of the corresponding fluxes and sources, as well as to the implementation of computationally efficient techniques for simulating the geometrical deformation of the workpiece, which in our setting is entirely determined by the motion of the weld pool surface.Common to all arc fusion welding processes is the employment of a welding arc. Many techniques rely on the arc to clean and shield the workpiece during the process, however in this study we consider it to be its main purpose to cause the local increase of thermal energy that is required for the establishment of the weld pool, and also to exert the mechanical forces that provoke the subsequent fluid flow which enhances heat transfer and facilitates weld penetration. The physics of the welding arc itself is quite intricate, and although the modelling of the arc is not the prime objective of this research project, we conclude that arc forces act on the pool surface, and that the investigation of the arc behaviour is important insofar that it provides input to the pool model and thus enables a more accurate prediction of the quality of the weldment that is created once the pool has solidified
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- Edstorp, Marcus, 1980
(författare)
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Weld Pool Simulations
- 2008
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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