Papers by Keyword: Heat Source Model

Abstract: Ring-seam joint pipe is more and more widely used in advanced auto-body assembly. However, Aluminums higher conductivity, higher convection coefficient, oxidability and low plasticity in high temperature compared to convectional low carbon steel make its welding numerical simulation much more difficult. Thermal simulation is the fundamental of aluminums coupled calculations of thermo-elasto-plastic for welding. In this paper, a pipe joint of ring seam for ZL114 aluminum alloy is numerically modeled based on birth-death element method and moving-heat-source function loading method. The simulation results agree well with the experiments, which shows that the double ellipsoid heat source model is most suitable for MIG welding simulation of aluminum alloy.

Abstract: Great interest of the laser beam welding in industry is a new theoretical task, making planning the welding procedure specification and the quality control of welded joints easier. Estimating and calculating the dimensions of a weld pool and temperature distribution near weld mainly concern heat source modelling. In the presented work calculations of welding pool shape and thermal field for cylindrical-powered-normally model of heat source have been presented. Parameters of the model of heat source and weld pool geometry were determined using analytical-numerical calculations. The results of numerical calculations were compared with the experimental data for butt joint made by CO₂ laser beam. Comparable results have been observed. Practical recommendations for assumptions of model parameters - the flux density energy distribution of the heat source in case of calculations of the thermal field in the vicinity of a weld pool are given.

Abstract: Thermal stresses of grinding plays an important role on the fatigue and wear resistance of the component. A comprehensive analysis of thermal stress induced by surface grinding has been conducted with aid of the finite element method. To obtain a reliable figure of thermal stress induced by grinding, temperature-dependent properties of workpiece materials were taken into account. The developed finite element procedure has also been applied to calculate the surface and sub-surface thermal stress induced by moving source of triangular heat when convection and radiation is occurred over the whole work. Based on an analysis of the effects of wheel velocity on the thermal stress distributions in an elastic-plastic solid, some important conclusions were given.

Abstract: Resistance spot welding (RSW) is being taken place by partial lap laser welding for the poor surface quality and bad airtight due to the pressure of electrodes. The shape of partial lap laser welding is similar to the vase. When the penetration of the joint is in a certain range, there is no welding trace on the outer surface. Laser welding temperature field numerical analysis based on Abaqus finite element analysis software is committed to obtain a suitable range of process parameters to improve production efficiency and automation by determining the joint penetration. To master the laser lap welding of stainless steel weld penetration state, the combination of three-dimensional positive cone + three-dimensional inverted cone + half-ellipsoid heat source model was established simulating stainless steel lap laser weld pool shape and forecasting the range of process parameters .

Abstract: The heat source model and the heat input model were built by analyzing welding process. The rationalities of model were verified by finite element simulation. The method of prestressed welding was employed in order to reduce welding residual stress. The welding residual stress would be widely impacted by imposed prestress of 90% yield strength welding. At the same time the propagation of welding heat cracking in the heat-affected zone was properly controlled by prestressed welding.

Abstract: From the laser welding actual process, the welding heat source model of laser welding process was established, that is, superposition heat source. According to the knowledge of thermodynamics, the establishment of a welding process, the mathematical model of temperature distribution of laser welding process was obtained by laser welding heat source. Finally, the finite element simulation of welding temperature distribution was used. The simulated results were compared with the analytical results of mathematical model of temperature field, it was proved consistent between simulated results and analytical results, at the same time it can account for the correctness of the mathematical model of temperature field.

Abstract: In the case of welding of T-joints in a special structure, the joining is realized through a total penetration of deck plates. For the deck plate’s thickness over 6 mm, high power MAG welding process should be applied. To help experimental optimizing of this welding technology, a 3D quasi-stationary numerical model was established to predict the penetration and weld form of the high power MAG welding on a thick plate. In the analysis a new volumetric heat source model was put forward which considers the heat directly from the arc und that from transferred droplets separately. Because the weld pool surface under the arc was strongly pressed, the droplet heat source in the model was located under the workpiece surface. The size of the droplet heat source model was determined on the base of physical principles and available experimental data. Using a commercial finite element software the weld form inclusive penetration under different welding parameters was then simulated. Through comparison with the experimental results the presented FE-model was verified.