During deep drawing process,the material parameters of blank have a significant effect on the quality of the drawn part and the determination of process parameters. Here,a 3D finite element model is developed for the ...During deep drawing process,the material parameters of blank have a significant effect on the quality of the drawn part and the determination of process parameters. Here,a 3D finite element model is developed for the deep drawing process of a thin-walled hemispheric surface part. Then the influences of material parameters including hardening exponent n,yield stress σs and elastic modulus E on the process are investigated by simulation. The results show that the effects of n and σs on punch force,thickness variation and equivalent strain are more notable. The maximum equivalent plastic strain occurs outside the die corner. However,when the value of n is 0.03 or σs is smaller than 120 MPa,higher equivalent plastic strain occurs at ball top.展开更多
Hydraulic counter pressure deep drawing of truncated conical part is numerically simulated with MARK and the nature of increasing the forming limit in this process is searched.The effects of blank holding force and c...Hydraulic counter pressure deep drawing of truncated conical part is numerically simulated with MARK and the nature of increasing the forming limit in this process is searched.The effects of blank holding force and chamber pressure on forming results are investigated by experiments and,as a result,truncated conical parts with large drawing ratio are successfully formed in single step with this drawing method.展开更多
The intelligent press forming of sheet metal is a completely new and comprehensive technology that combines control-science, computer science, material science and metal forming theory. Although the technology origina...The intelligent press forming of sheet metal is a completely new and comprehensive technology that combines control-science, computer science, material science and metal forming theory. Although the technology originated in 1980s from America, it was focused on the spring-back of V-shaped bending. Not until 1990s was some pioneering research conducted on the intellectualized control of cup-deep drawing. The research field is expanded to the axis-symmetric part and non-axis symmetric part. After a series of theoretical and experimental research, an intellectualized control system on the deep drawing processing of sheet metal is developed. The common general feature of sheet metal on the process of deep drawing is analyzed and a completely mechanical model is concluded and the deep drawing intellectualized control of sheet metal is finally realized.展开更多
Friction law is researched in rectangular parts deep drawing using simulation test ma-chine that is used to assess lubricants performance in deep drawing process. Friction coefficientsin different positions on die sur...Friction law is researched in rectangular parts deep drawing using simulation test ma-chine that is used to assess lubricants performance in deep drawing process. Friction coefficientsin different positions on die surface in deep drawing process are measured through probe sensors.Friction coefficients of flange corner, near straight border and far straight border are verified anddescribed quantitatively. It plays an important role in using appropriate lubricants in auto-bodypanel deep drawing process.展开更多
Inner wrinkling phenomenon is more likely to develop during hydrodynamic deep drawing （HDD） of complicated component-forms due to the higher demand for controlling deformation sequences. Aiming at the problems in co...Inner wrinkling phenomenon is more likely to develop during hydrodynamic deep drawing （HDD） of complicated component-forms due to the higher demand for controlling deformation sequences. Aiming at the problems in control of inner wrinkling for an irregular surface part featured with both concavity and convex, this research proposes an optimal design method of drawbead parameters to change the material flow. According to theoretical analysis of the mechanism of inner wrinkling, optimizing cavity pressure only is unreasonable to form a wrinkle-free deep-drawn part, so semi-circular drawbeads are employed. The effects of layout and height of drawbeads on forming results are discussed, and a process window is established based on evaluation indicators including the anti-wrinkle coefficient and the minimum wall thickness. Experiments are carried out to validate the process window, and the wall thickness and the wrinkle height are measured and compared with numerical findings. The results show that the anti-wrinkle ability of drawbeads weakens with increasing oblique angle and distance from the die center, while the wall thickness increases with increasing oblique angle and distance, and the inner wrinkling can be completely suppressed by drawbeads arranged in zones I and II with optimum penetration.展开更多
基金Project(2007CB613802) supported by the National Basic Research Program of ChinaProject(50805121) supported by the National Natural Science Foundation of China
文摘During deep drawing process,the material parameters of blank have a significant effect on the quality of the drawn part and the determination of process parameters. Here,a 3D finite element model is developed for the deep drawing process of a thin-walled hemispheric surface part. Then the influences of material parameters including hardening exponent n,yield stress σs and elastic modulus E on the process are investigated by simulation. The results show that the effects of n and σs on punch force,thickness variation and equivalent strain are more notable. The maximum equivalent plastic strain occurs outside the die corner. However,when the value of n is 0.03 or σs is smaller than 120 MPa,higher equivalent plastic strain occurs at ball top.
文摘Hydraulic counter pressure deep drawing of truncated conical part is numerically simulated with MARK and the nature of increasing the forming limit in this process is searched.The effects of blank holding force and chamber pressure on forming results are investigated by experiments and,as a result,truncated conical parts with large drawing ratio are successfully formed in single step with this drawing method.
基金Projects(59875074 50375136) supported by the National Natural Science Foundation of China
文摘The intelligent press forming of sheet metal is a completely new and comprehensive technology that combines control-science, computer science, material science and metal forming theory. Although the technology originated in 1980s from America, it was focused on the spring-back of V-shaped bending. Not until 1990s was some pioneering research conducted on the intellectualized control of cup-deep drawing. The research field is expanded to the axis-symmetric part and non-axis symmetric part. After a series of theoretical and experimental research, an intellectualized control system on the deep drawing processing of sheet metal is developed. The common general feature of sheet metal on the process of deep drawing is analyzed and a completely mechanical model is concluded and the deep drawing intellectualized control of sheet metal is finally realized.
文摘Friction law is researched in rectangular parts deep drawing using simulation test ma-chine that is used to assess lubricants performance in deep drawing process. Friction coefficientsin different positions on die surface in deep drawing process are measured through probe sensors.Friction coefficients of flange corner, near straight border and far straight border are verified anddescribed quantitatively. It plays an important role in using appropriate lubricants in auto-bodypanel deep drawing process.
基金supported by Chengdu Aircraft Industrial Corporation
文摘Inner wrinkling phenomenon is more likely to develop during hydrodynamic deep drawing （HDD） of complicated component-forms due to the higher demand for controlling deformation sequences. Aiming at the problems in control of inner wrinkling for an irregular surface part featured with both concavity and convex, this research proposes an optimal design method of drawbead parameters to change the material flow. According to theoretical analysis of the mechanism of inner wrinkling, optimizing cavity pressure only is unreasonable to form a wrinkle-free deep-drawn part, so semi-circular drawbeads are employed. The effects of layout and height of drawbeads on forming results are discussed, and a process window is established based on evaluation indicators including the anti-wrinkle coefficient and the minimum wall thickness. Experiments are carried out to validate the process window, and the wall thickness and the wrinkle height are measured and compared with numerical findings. The results show that the anti-wrinkle ability of drawbeads weakens with increasing oblique angle and distance from the die center, while the wall thickness increases with increasing oblique angle and distance, and the inner wrinkling can be completely suppressed by drawbeads arranged in zones I and II with optimum penetration.
