A mathematical model is developed for numerical analysis of thermal process in TIG welding with a moving arc, which is considered the double-elliptic distribution for both arc heat flux and arc pressure. An adjusting ...A mathematical model is developed for numerical analysis of thermal process in TIG welding with a moving arc, which is considered the double-elliptic distribution for both arc heat flux and arc pressure. An adjusting factor is introduced into the expression of arc pressure. The domain within which the arc heat flux is distributed non-symmetrically due to arc moving is selected appropriately, and three conditions for the domain to meet are described. The latent heat is taken into consideration by liquid fraction method. The dynamic development of weld pool geometry during TIG welding is analyzed numerically, and the effect of arc moving on the weld pool geometry is discussed. The experimental results show that the numerical analysis accuracy is obviously improved through taking the above-mentioned measures.展开更多
The forces acting on a gas tungsten arc （GTA） weld pool are analyzed. A model of static force condition for fullypenetrated weld pool is developed, and the criterion is set up to judge and evaluate the occurrence te...The forces acting on a gas tungsten arc （GTA） weld pool are analyzed. A model of static force condition for fullypenetrated weld pool is developed, and the criterion is set up to judge and evaluate the occurrence tendency of burn-through defect. Transient variations of the forces affecting the surfaces deformation and collapsing of weld pool are computed, and the percentages of their influencing roles are obtained. For specific material and workpiece thickness, the threshold values below which the burn-through phenomenon does not occur are determined, and compared with the experimental results.展开更多
The governing equations of surface-deformation in fully-penetrated GTAW weld pool are derived. The solution scheme of the Lagrange multiplier, which makes the top surface-deformation equation be coupled with that for ...The governing equations of surface-deformation in fully-penetrated GTAW weld pool are derived. The solution scheme of the Lagrange multiplier, which makes the top surface-deformation equation be coupled with that for the bottomsurface of a single weld pool, is given out. Through numerical analysis of weld pool surface-deformation in GTA W, it is found that there is clear correlation between the penetration extent and the Lagrange multiplier, in addition to the relationship between the penetration extent and the maximum depression and hump as well as the depressed volume of the top surface of weld pool. It lays good foundation for top-side sensing based weld penetration control.展开更多
基金the financial support for this project from the National Natural Science Foundation of China under Grant No.50475131.
文摘A mathematical model is developed for numerical analysis of thermal process in TIG welding with a moving arc, which is considered the double-elliptic distribution for both arc heat flux and arc pressure. An adjusting factor is introduced into the expression of arc pressure. The domain within which the arc heat flux is distributed non-symmetrically due to arc moving is selected appropriately, and three conditions for the domain to meet are described. The latent heat is taken into consideration by liquid fraction method. The dynamic development of weld pool geometry during TIG welding is analyzed numerically, and the effect of arc moving on the weld pool geometry is discussed. The experimental results show that the numerical analysis accuracy is obviously improved through taking the above-mentioned measures.
基金The authors are grateful to the financial support for this project from the National Natural Science Foundation of China under Grant No. 50475131.
文摘The forces acting on a gas tungsten arc （GTA） weld pool are analyzed. A model of static force condition for fullypenetrated weld pool is developed, and the criterion is set up to judge and evaluate the occurrence tendency of burn-through defect. Transient variations of the forces affecting the surfaces deformation and collapsing of weld pool are computed, and the percentages of their influencing roles are obtained. For specific material and workpiece thickness, the threshold values below which the burn-through phenomenon does not occur are determined, and compared with the experimental results.
基金the National Natural Science Foundation of China under Grant No50475131
文摘The governing equations of surface-deformation in fully-penetrated GTAW weld pool are derived. The solution scheme of the Lagrange multiplier, which makes the top surface-deformation equation be coupled with that for the bottomsurface of a single weld pool, is given out. Through numerical analysis of weld pool surface-deformation in GTA W, it is found that there is clear correlation between the penetration extent and the Lagrange multiplier, in addition to the relationship between the penetration extent and the maximum depression and hump as well as the depressed volume of the top surface of weld pool. It lays good foundation for top-side sensing based weld penetration control.
