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| 2. |
- Babu, Bijish, et al.
(författare)
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Physically based constitutive model for Ti-6Al-4V used in the simulation of manufacturing chain
- 2009
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Ingår i: Computational Plasticity X. - : International Center for Numerical Methods in Engineering (CIMNE). - 9788496736696
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Konferensbidrag (refereegranskat)abstract
- Simulations of manufacturing process chain involving forming, welding and heat treatment are complex because of the varying length and time scales and the range of temperatures which trigger the different associated deformation mechanisms. This paper demonstrates the use of a physically based constitutive model in simulation of a manufacturing chain.
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| 3. |
- Barsoum, Zuheir, et al.
(författare)
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Simplified FE welding simulation of fillet welds : 3D effects on the formation residual stresses
- 2009
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Ingår i: Engineering Failure Analysis. - : Elsevier BV. - 1350-6307 .- 1873-1961. ; 16:7, s. 2281-2289
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Tidskriftsartikel (refereegranskat)abstract
- In this study two- and three-dimensional finite element welding simulations have been carried out. The welded component studied is a T-type fillet weld which is frequently used in the heavy vehicle machine industry with plate thicknesses of eight and 20 mm, respectively. The software's used for the welding simulations is MSC.Marc and ANSYS. The objective is to study the formation of the residual stresses due to 3D effect of the welding process. Moreover, welding simulations using solid models and contact models in the un-fused weld roots were carried out in order to investigate the possible effect with respect to the residual stresses. Residual stress measurements were carried out using X-ray diffraction technique on the manufactured T-welded structure. The 2D residual stress predictions shows good agreement with measurements, hence the 2Dwelding simulation procedure is suitable for residual stress predictions for incorporation in further fatigue crack growth analysis from weld defects emanating from the weld toe and the un-fused root.
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| 4. |
- Lundbäck, Anna-Karin, et al.
(författare)
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Assembly of Kch, a putative potassium channel from Escherichia coli
- 2009
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Ingår i: Journal of Structural Biology. - : Elsevier BV. - 1047-8477 .- 1095-8657. ; 168:2, s. 288-293
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Tidskriftsartikel (refereegranskat)abstract
- Attempts to explore the structure and function of Kch, a putative potassium channel of Escherichia coli have yielded varying results; potassium-associated functions have been found in vivo but not in vitro. Here the kch gene is shown to produce two proteins, full-length Kch and the large C-terminal cytosolic domain (the RCK domain). Further, these two proteins are associated at the initial stages of purification. Previous structural studies of full-length Kch claim that the isolated protein forms large aggregates that are not suitable for analysis. The results presented here show that the purified protein sample, although heterogeneous, has one major population with a mass of about 400 kDa, implying the presence of two Kch tetramers in a complex form. A three dimensional reconstruction at 25 angstrom based on electron microscopy data from negatively stained particles, revealed a 210 angstrom long and 95 angstrom wide complex in which the two tetrameric Kch units are linked by their RCK domains, giving rise to a large central ring of density. The formation of this dimer of tetramers on expression or during purification, may explain why attempts to reconstitute Kch into liposomes for activity measurements have failed.
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| 5. |
- Lundbäck, Andreas, et al.
(författare)
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Simulation and validation of TIG-welding and post weld heat treatment of an Inconel 718 plate
- 2005
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Ingår i: Mathematical modelling of weld phenomena 7. - Graz : Techn. Univ. TYG. - 390135199X ; , s. 683-696
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Konferensbidrag (refereegranskat)abstract
- A finite element based model was used to simulate the thermal and mechanical response of a simple geometry TIG welded joint, validated through experiments. TIG welding experiments were carried out to produce butt welds in Inconel 718 sheets of thickness 3.2 mm, followed by heat treatment. Transient temperature and strain measurements were performed during welding; residual stress measurements were carried out after welding and after heat treatment. Calculated and measured welding temperature histories, strains and residual stresses were compared. The effect of buckling occurrence on the sensitivity of the model is noted.
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| 6. |
- Lundbäck, Andreas, et al.
(författare)
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Validation of three-dimensional finite element model for electron beam welding of Inconel 718
- 2005
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Ingår i: Science and technology of welding and joining. - 1362-1718 .- 1743-2936. ; 10:6, s. 717-724
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Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional finite element model for the prediction of the distortion and residual stresses induced during electron beam welding is described. The model is validated by butt welding experiments on two Inconel 718 plates. A particular effort is made to determine a good model for the heat input. A combined conical and double ellipsoid heat source is used to model the deep penetration characteristic of the electron beam and this source is calibrated using the results from a separate thermodynamic simulation, using the ELSIM finite difference code. Parallel computation is used to reduce the overall simulation time in the coupled thermomechanical simulation of welding. The agreement between calculations and experiments is good with respect to the residual stresses. Measured and computed deformations agree qualitatively although they differ in magnitude
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