MODEL OF LASER-TIG HYBRID WELDING HEAT SOURCE

The welding mechanism of laser-TIG hybrid welding process is analyzed. Withthe variation of arc current, the welding process is divided into two patterns: deep-penetrationwelding and heat conductive welding. The heat flow model of hybrid welding is presented. As todeep-penetration welding, the heat source includes a surface heat flux and a volume heat flux. Theheat source of heat conductive welding is composed of two Gaussian distribute surface heat sources.With this heat source model, a temperature field is calculated. The finite element code MARC isemployed for this purpose. The calculation results show a good agreement with the experimental data.

Investigation on automated loading of dynamic 3D heat source model for welding simulation

Since programing complex and dynamic heat source model for welding simulation is a complex job,the parametric methods are studied in this paper.Firstly,an overall flow to achieve automatically modeling welding was introduced.Secondly,an expert module rule for selecting welding heat source model was founded,which is based on simulation knowledge and experiences.Thirdly,a modularity routine method was investigated using writing with C++programing,which automatically creates subroutines of 3D dynamic heat source model for user.To realize the dynamic weld path,the local weld path coordinate system was moved in the global coordinate system and it is used to model the direction of weld gun,welding path and welding pose.The weld path data file was prepared by the automatic tool for the welding heat source subroutines.All above functions were integrated in the user interface and the connection with architecture was introduced.At last,a laser beam welding heat source modeling was automatically modeled and the weld pool geometry was compared with the reported literature.It demonstrated that the automated tool is valid for welding simulation.Since modeling became convenient for welding simulation using the tool proposed,it could be easy and useful for welding engineers to acquire the needed information.

Heat source analyses of dual laser-beam bilateral synchronous welding for T-joint

The DLBSW（ dual laser-beam bilateral synchronous welding） technology of T-type joint has been widely used for the connection of skins and stringers in airplane industry. To understand the thermodynamic and mechanical behavior of this process, it is necessary to establish a reasonable heat source model. Two different surface-body combination heat source models are adopted in this paper. Both models use the Gaussian surface heat source model and one is combined with the cone body heat source model and the other is combined with Gaussian rotator body heat source model. The simulation results of these two different models are investigated. And the temperature field results of DLBSW process for T-joint with two different heat sources are discussed. It is indicated that the combination heat source model is effective to simulate the DLBSW process and the current study is useful for more profound research in this field.

Modelling of the plasma-MIG welding temperature field

A three-dimensional simulation model for the plasma-MIG welding process, which takes the interaction between the plasma arc and MIG arc into account, is presented and the quasi-steady temperature fields on the workpiece are calculated with the model. The 10 mm-5A06 aluminum alloy is welded and the temperature fields are measured with the thermoelectric couple. The simulation results and measured results show that the biggest deviation of peak temperature between them is below 20 ℃, which indicates good coincidence between the simulation and measurement.

基于ABAQUS的EH36海工钢气电立焊数值模拟研究

为研究EH36海工钢气电立焊过程,以有限元软件ABAQUS为平台,建立了用于计算气电立焊焊接温度场和应力场的有限元模型。采用椭球体热源与高斯面热源的组合热源模型并通过DFLUX子程序实现,通过生死单元技术来控制焊缝的填充加载,通过实测得到EH36钢的热物理性能参数,模拟了气电立焊焊接过程。进行了焊接试验,并通过热电偶测得了焊板典型位置的热循环曲线。结果表明:焊后横向残余应力在立板的中间区域为拉应力,在其余区域为压应力。纵向残余应力在焊缝及其附近区域表现为较大的拉应力,而远离焊缝拉应力迅速衰减并过渡为压应力;计算得到的热循环曲线和焊缝形状与实际基本一致,表明了本文建立的气电立焊焊接模型的准确性。

Numerical analysis of thermal process in continuous drive radial friction welding

A heat source model for radial friction welding was proposed, which was determined by friction pressure, friction coefficient, material properties and extrusion speed of material. A 3D model was established to analyze the continuous drive radial friction welding temperature field of 45 steel pipe. The influences of friction pressure, friction time and rotation speed on the temperature of the friction interface were analyzed. The results showed that the temperature on the friction interface rapidly rose to a peak temperature in initial friction stage and kept constant in the stable friction stage. Welding parameters of friction pressure, friction time and rotation speed had few influences on the peak temperature, while the increase of frlctlon pressure and rotation speed could shorten the time to reach the peak temperature.

Numerical simulation of temperature field in deep penetration laser welding of 5A06 aluminum cylinder

Deep penetration laser welding temperature field of 5A06 aluminum alloy canister structure was simulated using the surface-body combination heat source model by ANSYS, which was made up of Gauss surface heat source model and Gauss revolved body heat source model. Convection, radiation and conduction were all con,sidereal during the simulation process. The thermal cycle curves of the points both on the shell outer surface and in the seam thickness direction were calculated. Simulated results agreed well with the experiment results. It concluded that the surface-body combination heat source model was fit for the temperature field simulation of deep penetration laser welding of the aluminum alloy canister structure. This method was proved to be an efficient way to predict the shape and dimension of welded joint for deep penetration laser welding of the aluminum alloy canister structure.

Finite element simulation of three-dimensional temperature field in underwater welding

Mathematical models of three-dimensional temperature fields in underwater welding with moving heat sources are built. Double ellipsoid Gauss model is proposed as heat sources models. Several factors which affect the temperature fields of underwater welding are analyzed. Water has little influence on thermal efftciency. Water convection coefftcient varies with the temperature difference between the water and the workpiece , and water convection makes molten pool freeze quickly. With the increase of water depth, the dimensions of heat sources model should be reduced as arc shrinks. Finite element technology is used to solve mathematical models. ANSYS software is used as finite element tool, and ANSYS Parametric Design Language is used to develop subprograms for loading the moving heat sources and the various convection coefftcients. Experiment results show that computational results by using double ellipsoid Gauss heat sources model accord well with the experimental results.

921A舰船钢激光-MAG复合焊接过程数值模拟分析

目的对厚度为16 mm的921A舰船钢进行激光-MAG复合焊接,得到最佳工艺参数,从数值模拟的角度验证焊接工艺的可靠性。方法利用SYSWELD+Visual-Environment软件对激光-MAG复合焊接过程进行数值模拟,选用3D高斯热源与双椭球热源相结合的复合热源模型对激光-MAG复合焊接过程进行仿真,绘制不同时刻及不同焊缝区域的时间-温度曲线,采用热弹塑性有限元法对应力变形场进行仿真计算。结果双椭球热源模型与3D高斯热源模型相结合的复合热源模型能够获得较为理想、接近真实热源形貌的热源形态;焊缝区域的焊接热源在行进过程中温度稳定,模拟热源温度可达3200℃,具有典型的焊接热循环曲线特征,且距离焊缝越远,升温速率和冷却速率越慢;焊接残余应力主要集中在焊缝处,约为440 MPa,且焊缝两端的结合部位具有较高的残余应力。结论复合热源模型适用于16 mm厚的921A钢激光-MAG复合焊接数值模拟,焊后板材的残余应力低于材料的屈服强度,冷却后板材的变形程度较小,最大变形量为1.13 mm,表明激光-MAG复合焊接方法及工艺适用于16 mm厚921A钢的焊接。

Research on modeling of heat source for electron beam welding fusion-solidification zone

In this paper, the common heat source model of point and linear heat source in the numerical simulation of electron beam welding （EBW） were summarized and introduced. The combined point-linear heat source model was brought forward and to simulate the welding temperature fields of EBW and predicting the weld shape. The model parameters were put forward and regulated in the combined model, which included the ratio of point heat source to linear heat source Qpr and the distribution of linear heat source Lr. Based on the combined model, the welding temperature fields of EBW were investigated. The results show that the predicted weld shapes are conformable to those of the actual, the temperature fields are reasonable and correct by simulating with combined point-linear heat source model and the typical weld shapes are gained.

Simulation of inverse heat conduction problems in fusion welding with extended analytical heat source models

纸为温度地论述围住的体积热来源和相应功能分析的表情。这里考虑的力量密度分布正常、指数、寓言。来源由于熔化和团结为象焊接的弧，激光横梁，电子横梁，等等，在焊接水池的传送对流以及潜伏的热一样的真实的热来源建模。热来源模型的参数是未知的 priori 并且不得不被解决一个反的热传导问题评估。为在靶子焊接的精明的 3D 温度地的功能分析的技术被开发。建议技术使更加为数据输入和答案减少全部的时间可能。它与激光横梁焊接钢盘子的一个例子被表明。

ANSYS有限元法在焊接温度场分析中的应用

通过对ANSYS在焊接温度场模拟应用的分析和总结,分别对ANSYS在焊接温度场模拟中热源理论基础、热源和边界条件的选择、温度场模拟步骤以及热循环模拟结果分析做了相应介绍,为具体研究ANSYS环境下的焊接温度场模拟与分析打下基础。

厚板铝合金YAG-MIG复合焊接温度场数值模拟

基于ANSYS软件,采用移动旋转高斯体热源函数加载,对12mm厚板铝合金YAG激光—MIG电弧复合焊接进行了温度场有限元数值模拟,模拟中综合考虑了对流、辐射和热传导对焊接热过程的影响,将模拟结果与相同工艺条件下实际的焊接试验结果进行了比较,验证了旋转高斯体热源模型在厚板铝合金复合焊接中的适应性。采用同样的数值模拟热源和试验模拟方法,同样得到了该铝合金5mm板模拟结果与实际结果相当一致的结论。从而为不同焊接工艺条件下铝合金中、厚板激光—电弧复合焊接焊缝形状和尺寸预测提供了一种有效的途径。

铝合金LB-VPPA复合焊接热源模型

激光-变极性等离子弧(Laser beam-variable polarity plasma arc,LB-VPPA)属双高能束新型复合焊接热源。采用Y4-S2型高速摄像检测了LB-VPPA复合焊接热源形态,在理论分析复合热源产热机理的基础上,利用Fortran语言对SYSWELD软件热源模型进行二次开发,建立能够实现正、反极性循环加载的LB-VPPA复合焊接热源模型。经与实际焊接熔池形状对比研究发现,熔池上部采用双椭球体热源,下部采用三维锥体热源,同时在小孔根部植入圆柱体热源的组合式热源模型与实际LB-VPPA复合焊接热源吻合。从模拟6 mm厚7A52铝合金板的VPPA焊和LB-VPPA复合焊接温度场分布结果发现,LB-VPPA复合焊能量更为集中,可以在平焊位置下实现穿孔型焊接。经实际焊接工艺试验验证了上述模拟结果的准确性。因此建立精确的LB-VPPA复合焊接热源模型对开展厚板铝合金LB-VPPA复合高效焊接提供强有力的理论支持。

基于BP和GA的激光焊接热源模型参数优化

通过BP神经网络与遗传算法GA对激光焊接有限元模拟中的热源模型参数进行优化,实现了对激光焊接温度场的精确模拟。选取面体热源模型对激光焊接温度场进行了有限元模拟,将模拟中难以确定并且对结果影响较大的热源有效功率系数、热能分配系数和热源作用半径作为输入量,以有限元模拟结果的误差作为输出量对BP神经网络进行训练,得到具有一定预测能力的神经网络,并形成结合神经网络和遗传算法的参数优化方法。结果表明,经过参数优化后的激光焊接有限元模拟具有较高的精度。

基于Simufact的大型钢结构架体焊接变形模拟分析与预测

为能够实现大型钢结构架体焊接变形的数值模拟,对架体的焊接特点进行了分析,简化分析模型,根据现有计算能力和容量确定有限元网格划分方法,建立了准确的热源模型,并完成大型钢结构架体焊接变形的模拟分析,实现了在特定焊接工艺条件下大型钢结构架体变形的准确预测。

基于ANSYS的焊接熔池传热速度对温度场影响的数值模拟

通过设定金属在熔点以上温度时不同等效导热系数,补偿ANSYS焊接温度场模拟时高斯表面热源的缺陷,研究电弧吹力和熔池液态金属对流共同作用下,熔池高温热交换速度变化对焊缝和热影响区粗晶区热循环的影响。结果表明,熔池高温传热速度对焊缝和热影响区800℃到500℃冷却时间的影响很小,用ANSYS软件模拟电弧吹力较大的焊接温度场时,若只考虑焊缝和热影响区800℃到500℃冷却时间时,采用高斯热源加载方式是可行的。

API X65管道深水铺设GMAW横向焊接温度场

为了应对管道深水铺设GMAW横向焊接熔池下坠、窄坡口、无衬垫等挑战,建立了管道三维模型并进行了网格划分,利用材料软件生成了API X65温度场材料数据库,通过模拟温度场云图与实际焊缝截面的匹配校核了Goldak双椭球热源模型,管道焊接温度场分布SYSWELD软件模拟结果与实际焊接过程相符合.建立了焊接温度场测试系统,通过背孔法埋设的热电偶测量了API X65管线钢平板焊接的热循环曲线.测试曲线与SYSWELD仿真曲线具有相同的温度升降趋势,上板节点温度也均明显低于下板节点温度.采用焊缝截面平均热循环曲线作为热源进行了多道焊模拟,并进行了试验.结果表明,多道焊焊接变形是由焊接工艺参数与残余应力释放共同确定的.

摇动电弧窄间隙GMAW焊温度场数值分析模型

从宏观传热学出发,依据横断面几何形状特征,综合考虑电弧摇动、接头几何特征及焊缝表面形状对电弧热流分布特征的影响,建立了摇动电弧窄间隙GMAW焊瞬态温度场数值分析模型.利用ANSYS软件对摇动电弧瞬态温度场及热循环曲线进行了模拟计算,分析了其分布特征.结果表明,模型能够合理、准确反映摇动电弧的移动轨迹及分布特性,且焊缝横断面的计算结果与试验结果吻合较好,从而证明了模型的准确性.在焊接电流为300A,摇动频率为2 Hz时,熔池形态变化有限.

基于FEA计算机模拟的激光透射轮廓焊接工艺

采用有限元分析和实验设计对激光透射轮廓焊接工艺进行系统模拟。通过开发的三维热源模型,模拟带有移动热源的激光透射轮廓焊接工艺。采用商业ANSYS多物理场有限元软件,通过实施高斯体积热源模型,并结合对流辐射边界条件,获得数值结果。将实验设计与回归分析结合,设计实验,并在仿真结果的基础上开发数学模型。四个关键工艺参数,即功率、焊接速度、光束直径以及吸收聚合物中碳黑含量作为自变量,而焊接面最高温度、焊缝宽度以及透明和吸收聚合物中焊缝深度作为因变量。灵敏度分析可以用来确定自变量的不同取值如何影响某个因变量。