Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve ...Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve the life of the dies in cold rotary forging.The purpose of this work is to reveal the contact force responses in cold rotary forging through the modelling and simulation.For this purpose,a 3D elastic-plastic dynamic explicit FE model of cold rotary forging is developed using the FE code ABAQUS/Explicit.Through the modelling and simulation,the distribution and evolution of the contact force in cold rotary forging is investigated in detail.The experiment has been conducted and the validity of the 3D FE model of cold rotary forging has been verified.The results show that: 1) The contact force distribution is complex and exhibits an obvious non-uniform characteristic in the radial and circumferential directions; 2) The maximum contact force between the upper die and the workpiece is much larger than that between the lower die and the workpiece; 3) The contact force evolution history is periodic and every period experiences three different stages; 4) The total normal contact force is much larger than the total shear contact force at any given time.展开更多
Stress analysis and optimization of combined die structure with two stress rings were performed.Using thermoelastic deformation,the contact pressure at the interfaces between layers was calculated.Then,theoretical exp...Stress analysis and optimization of combined die structure with two stress rings were performed.Using thermoelastic deformation,the contact pressure at the interfaces between layers was calculated.Then,theoretical expressions of stress distribution for the combined die were derived.The thermal-mechanical effect under working conditions was considered.To verify the theoretical expressions,simulation work was performed.Optimization of die design was carried out by defining radius ratio and shrink fit coefficient as optimization variables.The objective was to minimize the effective circumferential stress at the inner surface of the die insert,under the constraint that the maximum equivalent stress values of die insert and stress rings did not exceed their respective yield stresses.The Kriging model was used to describe the influence of shrink fit and die dimensions on the objective function and the maximum equivalent stress.Using a genetic algorithm,optimum parameters were found with a minimum circumferential stress of 442.9 MPa under a working stress of 1800 MPa.Further analysis of five selected optimal results was carried out,and the specific design parameters of these combined dies are different under the same level of circumferential stress,and the combined die is overdesigned if the thermal effect is ignored.展开更多
基金Project(51105287)supported by the National Natural Science Foundation of ChinaProject(2012BAA08003)supported by the Key Research and Development Project of New Products and New Technologies of Hubei Province,ChinaProject(2013M531750)supported by China Postdoctoral Science Foundation
文摘Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve the life of the dies in cold rotary forging.The purpose of this work is to reveal the contact force responses in cold rotary forging through the modelling and simulation.For this purpose,a 3D elastic-plastic dynamic explicit FE model of cold rotary forging is developed using the FE code ABAQUS/Explicit.Through the modelling and simulation,the distribution and evolution of the contact force in cold rotary forging is investigated in detail.The experiment has been conducted and the validity of the 3D FE model of cold rotary forging has been verified.The results show that: 1) The contact force distribution is complex and exhibits an obvious non-uniform characteristic in the radial and circumferential directions; 2) The maximum contact force between the upper die and the workpiece is much larger than that between the lower die and the workpiece; 3) The contact force evolution history is periodic and every period experiences three different stages; 4) The total normal contact force is much larger than the total shear contact force at any given time.
基金the National Natural Science Foundation of China(No.51475294)。
文摘Stress analysis and optimization of combined die structure with two stress rings were performed.Using thermoelastic deformation,the contact pressure at the interfaces between layers was calculated.Then,theoretical expressions of stress distribution for the combined die were derived.The thermal-mechanical effect under working conditions was considered.To verify the theoretical expressions,simulation work was performed.Optimization of die design was carried out by defining radius ratio and shrink fit coefficient as optimization variables.The objective was to minimize the effective circumferential stress at the inner surface of the die insert,under the constraint that the maximum equivalent stress values of die insert and stress rings did not exceed their respective yield stresses.The Kriging model was used to describe the influence of shrink fit and die dimensions on the objective function and the maximum equivalent stress.Using a genetic algorithm,optimum parameters were found with a minimum circumferential stress of 442.9 MPa under a working stress of 1800 MPa.Further analysis of five selected optimal results was carried out,and the specific design parameters of these combined dies are different under the same level of circumferential stress,and the combined die is overdesigned if the thermal effect is ignored.
