Investigation into hydromechanical reverse redrawing assisted by separate radial pressure—process development and theoretical verification

1997 ◽  
Vol 211 (6) ◽  
pp. 451-462 ◽  
Author(s):  
J B Kim ◽  
D W Lee ◽  
D Y Yang ◽  
C S Park
Keyword(s):  
Deep Drawing ◽  
Process Development ◽  
Radial Pressure ◽  
Fe Analysis ◽  
Navier Stokes ◽  
Chamber Pressure ◽  
Drawing Ratio ◽  
Rigid Plastic ◽  
Navier Stokes Equation ◽  
Forming Condition

High-quality cups with a deep drawing ratio of more than four cannot be simply drawn by conventional drawing and redrawing. A special technology is required to form cups of a high deep drawing ratio. In the present study, after the conventional mechanical deep drawing process, subsequent hydromechanical reverse redrawing with controlled radial pressure has been developed. In order to increase the deep drawing ratio by more than four, the radial pressure is controlled independently of the chamber pressure and thus an optimum forming condition can be determined by varying the radial pressure. The process has been verified by a rigid-plastic finite element (FE) analysis considering all the external force boundary conditions induced by the hydrostatic pressure. The pressure distribution on the sheet is calculated numerically from the simplified Navier-Stokes equation. Through the experiment and the FE analysis, it has been shown that hydromechanical reverse redrawing assisted by separate radial pressure, developed in the present study, helps to increase the drawability of cylindrical cups, and thus it is useful when forming long cups.

Investigation of Forming Cylindrical Parts in a Modified Hydrodynamic Deep Drawing Assisted by Radial Pressure With Inward Flowing Liquid

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Milad Sadegh Yazdi ◽  
Mohammad Bakhshi-Jooybari ◽  
Hamid Gorji ◽  
Mohsen Shakeri ◽  
Maziar Khademi
Keyword(s):  
Deep Drawing ◽  
Thickness Distribution ◽  
Radial Pressure ◽  
Chamber Pressure ◽  
Drawing Ratio ◽  
Forming Force ◽  
Flowing Liquid ◽  
Hydrodynamic Deep Drawing ◽  
Study Results ◽  
Formed Part

Among the sheet hydroforming processes, hydrodynamic deep drawing (HDD) process has been used to form complex shapes and can produce parts with high drawing ratio. Studies showed that radial pressure created on the edge of the sheet can decrease the drawing force and increase drawing ratio. Thus, increasing of radial pressure to an amount greater than chamber pressure, and independent control of these pressures, is the basic idea in this study. In this research, the effect of radial and chamber pressures on formability of St13 and pure copper sheets in the process of hydrodynamic deep drawing assisted by radial pressure (HDDRP) with inward flowing liquid is investigated. Giving that a significant portion of the maximum thinning of the formed part occurs in the beginning of the process, the pressure supply system used in the experimental tests was designed in a way, which provides simultaneous control of the radial and chamber pressures throughout the process. Thickness distribution, forming force, and tensile stresses are the parameters that were evaluated in this study. Results indicated that using a higher radial pressure than the chamber pressure and controlling their values in the initial stages of the process enhances the thickness distribution of the formed part in all regions. A comparison between the thickness distribution and maximum forming force of the formed parts by the HDDRP and HDDRP with inward flowing liquid methods showed that by applying the later method, parts with more uniform thickness distribution and less maximum thinning and forming force can be achieved.

Process analysis of hydrodynamic deep drawing of cone cups assisted by radial pressure

2015 ◽  
Vol 231 (10) ◽  
pp. 1793-1802 ◽  
Author(s):  
Alireza Jalil ◽  
Mohammad Hoseinpour Gollo ◽  
SM Hossein Seyedkashi
Keyword(s):  
Deep Drawing ◽  
Critical Pressure ◽  
Process Analysis ◽  
Fluid Pressure ◽  
Radial Pressure ◽  
Strain Hardening Exponent ◽  
Geometrical Parameters ◽  
Drawing Ratio ◽  
Hydrodynamic Deep Drawing ◽  
Rupture Pressure

Forming of flat sheets into shell conical parts is a complex manufacturing process. Hydrodynamic deep drawing process assisted by radial pressure is a new hydroforming technology in which fluid pressure is applied to the peripheral edge of the sheet in addition to the sheet surface. This technique results in higher drawing ratio and dimensional accuracy, better surface quality, and ability of forming more complex geometries. In this research, a new theoretical model is developed to predict the critical rupture pressure in production of cone cups. In this analysis, Barlat–Lian yield criterion is utilized and tensile instability is considered based on the maximum load applied on the sheet. The proposed model is then validated by a series of experiments. The theoretical predictions are in good agreement with the experimental results. The effects of geometrical parameters and material properties on critical rupture pressure are also studied. The critical pressure is increased with increase in the height ratio, strain hardening exponent, and anisotropy. Higher punch nose radius expands the safe zone. It is shown that the critical pressure decreases for drawing ratios higher than 4.

Sensitivity Analysis of Hydro-Rim Deep Drawing of Cylindrical Cups

Manufacturing ◽  
2003 ◽  
Author(s):  
Jeries J. Abou-Hanna ◽  
Timothy McGreevy ◽  
Abdalla Elbella ◽  
Haithem Algousi
Keyword(s):  
Finite Element ◽  
Deep Drawing ◽  
Material Model ◽  
Chamber Pressure ◽  
Process Conditions ◽  
Plastic Behavior ◽  
Drawing Ratio ◽  
Real Time Control ◽  
Time Control ◽  
Punch Speed

Extensive nonlinear finite element analyses were conducted to help predict practical test conditions of intelligent hydro-rim deep forming of cylindrical cups under controlled cooled punch and heated blank temperatures, punch speed, chamber and rim pressures, and punch friction. The study focused on finding practical process conditions for maximizing the drawing ratio by variations in blank and punch temperatures, friction, rim pressure, chamber pressure, and punch speed. The study was based on an experimental cell that aimed at using real time control of the mentioned parameters to delay the necking process. The finite element material model considered the plastic behavior to be strain rate and temperature dependent. While conventional deep drawing is limited to a Limit Drawing Ratio (LDR) of about 2, the results show that a parameters listed above. Blank temperature, punch friction, rim pressure, and chamber pressure provide significant influence of various degrees on increasing the cup drawing ratio. Blank heating is very effective, but does not by itself guarantee higher LDR. The presence of punch friction coupled with chamber pressure tends to delay the necking and moves the latter up along the cup wall and away from the cup bottom corner. Rim pressure, while difficult to implement, results in significant improvement of the LDR, since it helps push the material into the die, and in doing so reduces the cup-wall tension that causes the material instability. High rim pressure, on the other hand, increases the blank thickness resulting in increased blank holder loads. Punch temperature does not play as critical a role as the blank temperature in maintaining a high LDR under the conditions investigated. The study revealed that punch speed had to be above a certain critical level for a LDR of 4. However, increased punch speed proved to cause higher variations in the thickness along cup wall. It is important to mention that the results of this study do not necessarily apply to all metals; copper material was used here. Metals with low ductility, for example would react differently, a subject of future studies.

Theoretical, numerical and experimental investigation of hydro-mechanical deep drawing of steel/polymer/steel sandwich sheets

2018 ◽  
Vol 233 (5) ◽  
pp. 1529-1546 ◽  
Author(s):  
Majid Fazlollahi ◽  
Mohammad Reza Morovvati ◽  
Bijan Mollaei Dariani
Keyword(s):  
Deep Drawing ◽  
Fluid Pressure ◽  
Chamber Pressure ◽  
Drawing Ratio ◽  
Drawing Process ◽  
Forming Force ◽  
Limit Drawing Ratio ◽  
Deep Drawing Process ◽  
Sandwich Sheet ◽  
Sandwich Sheets

Fabricating flat sandwich sheets into components with a required shape and dimensions is a challenging job in the metal forming field. In this article, hydro-mechanical deep drawing was used for sandwich sheet forming. The aim of the work is to achieve higher drawing ratio of these sheets. Theoretical, numerical and experimental analysis of the hydro-mechanical deep drawing of sandwich sheets was carried out. Separated layers theory method is used for theoretical analysis of the process. Then, the numerical simulation of the process was developed by finite element method. The effect of core layer thickness on the forming force of the sandwich sheet and effective parameters of the process such as strain and forming force was investigated. Experimental works were conducted on the steel/polymer/steel sandwich sheets by a hydro-mechanical deep drawing die. A good agreement was observed between theoretical, numerical and experimental results. The safe zone of fluid pressure for achieving a part without rupture was obtained. It was shown that the limit drawing ratio is increased by increasing the pressure but after a particular point, the limit drawing ratio is decreased by increasing the chamber pressure. It was also observed that maximum drawing ratio for achieving a part without rupture in the hydro-mechanical deep drawing process is higher than conventional deep drawing process.

scholarly journals Investigation of a Modified Hydrodynamic Deep Drawing Assisted by Radial Pressure with Inward Flowing Liquid Process

2018 ◽  
Vol 190 ◽  
pp. 09003
Author(s):  
Maziar Khademi ◽  
Milad Sadegh yazdi ◽  
Mohammad Bakhshi-Jooybari ◽  
Hamid Gorji
Keyword(s):  
Deep Drawing ◽  
Thickness Distribution ◽  
Radial Pressure ◽  
Drawing Ratio ◽  
Cavity Pressure ◽  
Flowing Liquid ◽  
Hydrodynamic Deep Drawing ◽  
Simultaneous Control ◽  
Die Set ◽  
Cylindrical Parts

Hydrodynamic Deep Drawing (HDDRP), the combination of hydroforming and conventional deep drawing, accommodates the advantages of the two processes. A technique, called HDDRP with inward flowing liquid, has been introduced based on the idea of insertion of radial pressure around the blank rim. The radial pressure created on the blank edge, can increase the drawing ratio. Thus, increasing the radial pressure to an amount greater than the cavity pressure, and independent control of these pressures is the basic idea of this research for forming cylindrical parts. To perform the experiments, two independent pumps were used to provide the two pressures independently. The pressure supply system and the die set were designed in a way that provides simultaneous control of the pressures throughout the process. Then, the effects of radial pressure paths on thickness distribution of cylindrical St13 cups were investigated. In addition, a comparison between HDDRP and HDDRP with inward flowing liquid processes has been performed experimentally. Results indicated that using a higher radial pressure than the cavity pressure and controlling their values at any moment of the process enhances the thickness distribution of the formed part in all regions.

scholarly journals An Incompressible Polymer Fluid Interacting with a Koiter Shell

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Dominic Breit ◽  
Prince Romeo Mensah
Keyword(s):  
Moving Boundary ◽  
Classical Model ◽  
Elastic Shell ◽  
Planck Equation ◽  
Navier Stokes ◽  
Flexible Shell ◽  
Navier Stokes Equation ◽  
Shell System ◽  
Forward Equation ◽  
Polymer Fluid

AbstractWe study a mutually coupled mesoscopic-macroscopic-shell system of equations modeling a dilute incompressible polymer fluid which is evolving and interacting with a flexible shell of Koiter type. The polymer constitutes a solvent-solute mixture where the solvent is modelled on the macroscopic scale by the incompressible Navier–Stokes equation and the solute is modelled on the mesoscopic scale by a Fokker–Planck equation (Kolmogorov forward equation) for the probability density function of the bead-spring polymer chain configuration. This mixture interacts with a nonlinear elastic shell which serves as a moving boundary of the physical spatial domain of the polymer fluid. We use the classical model by Koiter to describe the shell movement which yields a fully nonlinear fourth order hyperbolic equation. Our main result is the existence of a weak solution to the underlying system which exists until the Koiter energy degenerates or the flexible shell approaches a self-intersection.

Production of Tapered Cups by Sequential Deep Drawing of Sheet Metals Using Drawn Cups as a Part of Punch

1993 ◽  
Vol 115 (2) ◽  
pp. 224-229 ◽  
Author(s):  
K. Yamaguchi ◽  
K. Kanayama ◽  
M. H. Parsa ◽  
N. Takakura
Keyword(s):  
Deep Drawing ◽  
Drawing Ratio ◽  
Drawing Process ◽  
Sheet Metals ◽  
Deep Drawing Process ◽  
Drawing Method

A new deep drawing process of sheet metals is developed to facilitate small-lot production of deep cups with large drawing ratio. In this process, unlike the conventional deep drawing method, a few drawn cups are always stacked on the punch and used as a part of punch for the subsequent deep drawing of a given blank. Before drawing a new blank, a drawn cup which is in contact with the punch is stripped off. The repetition of such stripping and drawing operations makes it possible to carry out both the first-stage drawing and the subsequent slight redrawings in one drawing operation using only one pair of punch and die. In this paper, this new deep drawing process is applied to the production of tapered cups and the main feature of the process is shown.

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