The roll forming process is applied to the manufacturing of high frequency welded (HFW) pipes,section steels,etc. In this paper,the roll forming process of the HFW pipe is simulated with the finite element method (FEM...The roll forming process is applied to the manufacturing of high frequency welded (HFW) pipes,section steels,etc. In this paper,the roll forming process of the HFW pipe is simulated with the finite element method (FEM). A user-defined material routine of the commercial finite element code ABAQUS/Explicit is developed,and the mixed hardening constitution model is realized through the user-defined material routine. Based on the mixed hardening constitutive equation,the numerical simulation of roll forming process of HFW pipe is performed. The evolutions of equivalent stress and strain are analyzed,and the calculated results are also compared between different hardening models. The results show that the different material hardening models have some important effects on the variation of equivalent stress and strain of strip steel during the simulation of the roll forming process.展开更多
A simulation method for microscopic creep damage at grain boundaries in the fine-grain heat-affected zone of low-alloy steel welds involving high energy piping was proposed on the basis of the combination of elastic-c...A simulation method for microscopic creep damage at grain boundaries in the fine-grain heat-affected zone of low-alloy steel welds involving high energy piping was proposed on the basis of the combination of elastic-creep FEM (finite element method) analysis and random fracture resistance modeling of the materials. The procedure to determine the initiation and growth-driving forces of small defects were briefly described. Then, a simulation procedure combining the stress distribution from elastic-creep FEM and the random fracture resistance model was proposed, and Ms procedure was applied to the simulation of the microscopic damage progress in a welded joint model test and in actual power piping. The results in terms of the simulated number density of small defects throughout the wall thickness were in good agreement with the observed results.展开更多
高频感应焊接的机理研究十分复杂,影响到焊接钢管高频加热温度分布的工艺参数众多,且影响程度和影响规律不尽相同。本文在建立的高频焊管主要电磁工艺参数和目标函数的映射模型基础上,利用改进的非支配排序遗传算法对直缝焊管高频感应...高频感应焊接的机理研究十分复杂,影响到焊接钢管高频加热温度分布的工艺参数众多,且影响程度和影响规律不尽相同。本文在建立的高频焊管主要电磁工艺参数和目标函数的映射模型基础上,利用改进的非支配排序遗传算法对直缝焊管高频感应焊接参数进行优化。对优化得到的Pareto最优解集进行综合分析,最终确定了该工况下当开口角为6°、电流频率为218.39 k Hz、线圈到V点距离为255 mm时,所对应的优化目标值均较小,其所对应焊缝的焊接质量较好。本文的研究为进一步提高高频焊管的焊接质量提供了理论依据。展开更多
基金the National Natural Science Foundation of China (No. 50375095)
文摘The roll forming process is applied to the manufacturing of high frequency welded (HFW) pipes,section steels,etc. In this paper,the roll forming process of the HFW pipe is simulated with the finite element method (FEM). A user-defined material routine of the commercial finite element code ABAQUS/Explicit is developed,and the mixed hardening constitution model is realized through the user-defined material routine. Based on the mixed hardening constitutive equation,the numerical simulation of roll forming process of HFW pipe is performed. The evolutions of equivalent stress and strain are analyzed,and the calculated results are also compared between different hardening models. The results show that the different material hardening models have some important effects on the variation of equivalent stress and strain of strip steel during the simulation of the roll forming process.
文摘A simulation method for microscopic creep damage at grain boundaries in the fine-grain heat-affected zone of low-alloy steel welds involving high energy piping was proposed on the basis of the combination of elastic-creep FEM (finite element method) analysis and random fracture resistance modeling of the materials. The procedure to determine the initiation and growth-driving forces of small defects were briefly described. Then, a simulation procedure combining the stress distribution from elastic-creep FEM and the random fracture resistance model was proposed, and Ms procedure was applied to the simulation of the microscopic damage progress in a welded joint model test and in actual power piping. The results in terms of the simulated number density of small defects throughout the wall thickness were in good agreement with the observed results.
文摘高频感应焊接的机理研究十分复杂,影响到焊接钢管高频加热温度分布的工艺参数众多,且影响程度和影响规律不尽相同。本文在建立的高频焊管主要电磁工艺参数和目标函数的映射模型基础上,利用改进的非支配排序遗传算法对直缝焊管高频感应焊接参数进行优化。对优化得到的Pareto最优解集进行综合分析,最终确定了该工况下当开口角为6°、电流频率为218.39 k Hz、线圈到V点距离为255 mm时,所对应的优化目标值均较小,其所对应焊缝的焊接质量较好。本文的研究为进一步提高高频焊管的焊接质量提供了理论依据。
