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Showing papers on "Hydroforming published in 2006"


Journal ArticleDOI
TL;DR: In this article, the cutting plane algorithm for the integration of a general class of elasto-plastic constitutive models was used to implement this yield function into the commercial FEM code LS-Dyna as a user material subroutine (UMAT).

128 citations


Journal ArticleDOI
TL;DR: In this article, an experimental and numerical simulation was conducted to investigate hydroforming of automotive rectangular-section structural components and the results were used as guidelines for some prototypes, and the effect of loading path on the failures and thickness distribution was discussed and the reasons were analyzed for the failures, such as bursting and folding.
Abstract: An experimental and numerical simulation was conducted to investigate hydroforming of automotive rectangular-section structural components and the results were used as guidelines for some prototypes. The effect of loading path on the failures and thickness distribution was discussed and the reasons were analyzed for the failures, such as bursting and folding. Hydroforming with axial feeding is strongly sensitive to the loading path. Bursting occurs in transition zone in the calibration when the internal pressure increases faster than the axial feeding. Otherwise, folding will take place due to too much axial feeding. There is the maximum thickness at central point of the side of cross-section and the minimum thickness at the transition area. If the n value of the tube material is bigger, the thickness of the final part will be more uniform. By using a petal-like perform section shape, the pressure for forming the transition radii was greatly reduced and components with small radii can be formed with relatively low pressure.

76 citations


Journal ArticleDOI
TL;DR: In this paper, a multi-objective optimization approach is proposed by simultaneously maximizing the bulge ratio and minimizing the thinning ratio, which is solved by using a goal attainment method.
Abstract: Tube hydroforming is an attractive manufacturing technology which is now widely used in many industries, especially the automobile industry. The purpose of this study is to develop a method to analyze the effects of the forming parameters on the quality of part formability and determine the optimal combination of the forming parameters for the process. The effects of the forming parameters on the tube hydroforming process are studied by finite element analysis and the Taguchi method. The Taguchi method is applied to design an orthogonal experimental array, and the virtual experiments are analyzed by the use of the finite element method (FEM). The predicted results are then analyzed by the use of the Taguchi method from which the effect of each parameter on the hydroformed tube is given. In this work, a free bulging tube hydroforming process is employed to find the optimal forming parameters combination for the highest bulge ratio and the lowest thinning ratio. A multi-objective optimization approach is proposed by simultaneously maximizing the bulge ratio and minimizing the thinning ratio. The optimization problem is solved by using a goal attainment method. An example is given to illustrate the practicality of this approach and ease of use by the designers and process engineers.

59 citations


Journal ArticleDOI
TL;DR: In this article, a database-assisted fuzzy process control algorithm was applied to T-branch forming with a counterpunch, and the results showed that the fuzzy control algorithm and virtual control system can provide an adequate loading path in the hydroforming process for an aluminum alloy tube.
Abstract: In this study, to determine the optimal loading path of tube hydroforming process, a database-assisted fuzzy process control algorithm proposed previously by the authors was applied to T-branch forming with a counterpunch. The tubular material used is aluminum alloy (A6063-T1) and has an outer diameter of 42.7 mm and wall thickness of 1.2 mm. Control variables is axial feed, counterpunch displacement, and internal pressure. The first two variables are dependent on the last one, which is an independent variable. In the control algorithm, new evaluation functions are adopted for buckling at the shoulder part of the branch and for contact fitting with a counterpunch. For a “virtual control system” including fuzzy algorithm with the evaluation functions, an explicit dynamic finite element code is used in the simulation. The experiments are carried out using a fuzzy controlled path obtained by the virtual control system, compared with the conventional manual control path that is attained by a trial-and-error approach. As a result, a T-branch product is successfully hydroformed. This result shows that the fuzzy control algorithm and virtual control system can provide an adequate loading path in the hydroforming process for an aluminum alloy tube.

56 citations


Journal ArticleDOI
TL;DR: In this article, the influence of wrinkling behavior on formability and thickness distribution in tube hydroforming was investigated and the wrinkles can be classified into three categories, i.e. useful wrinkles, dead wrinkles, and bursting wrinkles.

55 citations


Journal ArticleDOI
TL;DR: In this article, the authors summarized some of their experiences of tube and sheet hydroforming process design by simulation technique through actual try-out and suggested necessary improvements in the design procedure.

50 citations


Journal ArticleDOI
TL;DR: In this article, a Taylor-type polycrystalline model was developed and implemented into ABAQUS/Explicit finite element (FE) code using VUMAT to calculate the crystallographic texture evolution during the hydroforming of an extruded aluminum tube.

48 citations


Journal ArticleDOI
TL;DR: In this paper, the stress distribution and deformation pattern of the corner are analyzed by mechanical analysis and numerical simulation, and the effect of the friction coefficient on stress distribution is also considered. And the authors reveal the reasons of the local thinning and provide the clues to avoid the defect at the transition region.

44 citations


Journal ArticleDOI
TL;DR: In this article, the classical formulations for material forming either in the solid or in the liquid state are briefly recalled, in terms of material constitutive behavior, friction law, integral forms and finite element discretization.
Abstract: The classical formulations for material forming either in the solid or in the liquid state are briefly recalled, in terms of material constitutive behavior, friction law, integral forms and finite element discretization. A few important numerical issues are discussed, including meshing, remeshing and adaptivity, parallel computing and coupling between work-piece and tools. Five examples of applications of finite element models to new processes are presented: friction stir welding, hot stamping of quenchable steels, tube hydroforming, thixoforming and self piercing riveting. It is concluded that many new forming processes can be designed and optimized much more effectively using the numerical simulation technology.

40 citations


Journal ArticleDOI
TL;DR: In this article, the influence of temperature on the mechanical properties of 5A02 aluminum tube was investigated by uni-axial tensile test and hydrobulge test and the results showed the same changing tendency of the formability of aluminum tube at elevated temperature.

40 citations


Journal ArticleDOI
Takayuki Hama1, T. Ohkubo1, Ken Kurisu1, Hitoshi Fujimoto1, Hirohiko Takuda1 
TL;DR: In this paper, a finite-element simulation of the tube hydroforming process with rectangular dies is carried out for various loading paths, and the reasons why the loading paths of the so-called pressure advanced type, in which the hydraulic pressure is raised to a certain magnitude in advance of the axial pushing, are effective to obtain good formability are investigated in detail.

Journal ArticleDOI
TL;DR: In this paper, the effects of the coefficient of friction, strain hardening exponent and fillet radius on the parameters, protrusion height, thickness distribution and clamping and axial forces were studied.

Journal ArticleDOI
TL;DR: In this paper, a multi-layer tube has been studied experimentally and by FE simulation by applying both internal pressure and in-plane compressive load as the main forming loads and the simulation results have been verified by experiment on the basis of the deformation states of the formed components.

Book
01 Jan 2006
TL;DR: In this paper, a comprehensive reference on sheet metal forming and fabrication provides state-of-the-art reference information for product and production engineers for sheet metal fabrication technologies, selection of equipment and die materials, specification of forming practices for specific alloys, and new techniques for process design and control.
Abstract: This comprehensive reference on sheet metal forming and fabrication provides state-of-the-art reference information for product and production engineers. Coverage addresses all methods of sheet metal fabrication technologies, selection of equipment and die materials, specification of forming practices for specific alloys, and new techniques for process design and control. This Volume provides you with practical reference information on the basic processes of press forming, drawing, bending, spinning, shearing, blanking, and piercing of sheet with additional coverage on forming with bar, tube, wire, shapes, or long parts. New content areas include: Expanded coverage on computer-based methods for process simulation and control Advanced high-strength steels (AHSS) forming and material developments Expanded coverage on the evaluation and mitigation of springback and the troubleshooting of formability problems Rapid prototyping and die-less flexible manufacturing techniques such as thermal forming and peen forming Updates on cold-work powder metallurgy tool steels and tool coatings Updates and addition of practical reference information on basic operations of bending, press forming, and press brake forming Application of tailor weld blanks New process related developments in superplastic forming and conventional forming of aluminum, titanium, nickel, magnesium, and refractory alloys Recent process modifications in hydroforming and high-velocity metal forming Contents Include: Introduction to Forming Processes Shearing, Cutting, Blanking, and Piercing Equipment for Forming of Sheet Metal Tooling and Fabrication for Forming Sheet, Strip, and Plate Forming Processes for Sheet, Strip, and Plate Forming of Bar, Tube, and Wire Sheet Forming of Specific Ferrous and Nonferrous Metals Formability Analysis Process Design and Modeling for Sheet Forming Reference Information Index

Journal ArticleDOI
TL;DR: In this article, a mathematical model considering the forming tube as an ellipsoidal surface is proposed to examine the plastic deformation behavior of a thin-walled tube during the tube bulge hydroforming process in an open die, and thus different loading paths are gained based on this model.
Abstract: To investigate the effect of the loading path on the forming result and get the reasonable range of the loading path in tube bulge hydroforming process, a mathematical model considering the forming tube as an ellipsoidal surface is proposed to examine the plastic deformation behavior of a thin-walled tube during the tube bulge hydroforming process in an open die, and thus different loading paths are gained based on this model. The finite element code Ls-Dyna is also used for simulating the tube bulge hydroforming process. The effect of the loading paths on the bulged shape and the wall thickness distribution of the tube are discussed, and then the reasonable range of the loading path for the tube bulge hydroforming process is determined.

Patent
10 Nov 2006
TL;DR: In this article, a method of patching a well or a pipe by hydroforming a tubular metal patch is described, in which a tool (1) is inserted inside the patch so that the packers (3) are in register with the end portions (5) of the patch; inserting the assembly constituted by the tool and the patch (4) axially inside the well or the pipe, and positioning the assembly inregister with the zone for patching.
Abstract: A method of patching a well or a pipe by hydroforming a tubular metal patch, the method comprising the following steps: - inserting inside the patch (4) a tool (1) provided with a pair of inflatable packers (3) that are axially spaced apart from each other by a distance that is substantially equal to the length of the patch; - positioning the tool (1) inside the patch so that the packers (3) are in register with the end portions (5) of the patch; - inserting the assembly constituted by the tool (1) and the patch (4) axially inside the well or the pipe, and positioning the assembly in register with the zone for patching; - inflating the packers (3) to high pressure, sufficient for radially expanding the end portions (5) of the patch and pressing them in leaktight manner against the wall of the well or the pipe; and - deflating the packers (3) and withdrawing the tool (D - The method is applicable to the oil industry.

Journal ArticleDOI
TL;DR: In this article, an analytical prediction of bursting failure on tube hydroforming processes under combined internal pressure and independent axial feeding is carried out based on plastic instability, and three different classical necking criteria are introduced.
Abstract: Based on plastic instability, an analytical prediction of bursting failure on tube hydroforming processes under combined internal pressure and independent axial feeding is carried out. Bursting is an irrecoverable phenomenon due to local instability under excessive tensile stresses. In order to predict the bursting failure, three different classical necking criteria – diffuse necking criteria for a sheet, and a tube, and a local necking criterion for a sheet – are introduced. The incremental theory of plasticity for an anisotropic material is adopted and the hydroforming limit, as well as a diagram of bursting failure with respect to axial feeding and hydraulic pressure are presented. In addition, the influences of material properties such as anisotropy parameter, strain hardening exponent and strength coefficient on plastic instability and bursting pressure are investigated. As a result of the above approach, the hydroforming limit with respect to bursting failure is verified with experimental results.

Journal ArticleDOI
TL;DR: In this paper, a process strategy to join hollow workpieces angularly and to shape them simultaneously is presented, where the main focus is joining without welding, which is realized with a fluid-based force fit.

Patent
12 Jun 2006
TL;DR: An apparatus for forming a workpiece into a useful product using a pressurized fluid, also termed as "hydroforming" is described in this paper, where the workpiece may be a tube or may be one or a plurality of sheets of a material.
Abstract: An apparatus ( 10, 110 ) and method to form a workpiece ( 32, 132 ) into a useful product ( 28, 128 ) using a pressurized fluid ( 14 ), also termed as “hydroforming”. The workpiece may be a tube or may be one or a plurality of sheets of a material. The apparatus has a chamber ( 12 ) adapted to contain a quantity of a fluid, a hydroforming means positioned within the chamber, and means for substantially immersing the workpiece in the fluid before, during and after the hydroforming operation. Dies ( 16, 18 ) enclose the workpiece and provide a cavity of desired shape against which the workpiece is expanded by the pressurized fluid. The chamber may be open or closed to the atmosphere during operation and the fluid temperature and/or level may be controlled.

Patent
01 Feb 2006
TL;DR: In this article, the authors describe a set of sealing arrangements for sealing the ends of a tube-formed blank (16) placed in the mold, each of which includes a ring (30, 35) with a thin wall that fits into the inner surface of the tube (16), and a plug (33, 36) that can be displaced in an axial direction mounted axially inside of the ring, and an arrangement (32,37) for initially drawing the plug and the ring together form a seal.
Abstract: A hydroforming unit comprises a mould (19,20) that can be opened and sealing arrangements (30-33; 35-39) for sealing the ends of a tube-formed blank (16) placed in the mould,each one of the sealing arrangements (30-33; 35-39) comprises a ring (30, 35) with a thin wall that fits into the inner surface of the tube (16), and a plug (33, 36) that can be displaced in an axial direction mounted axially inside of the ring, and an arrangement (32,37) for initially drawing the plug (33, 36) outwards to put the ring under elastic tension against the inside of the tube-formed blank so that the plug and the ring together form a seal.

Journal ArticleDOI
TL;DR: In this article, the authors present some results of their research activity aimed to enhance the sheet hydroforming process using a movable inferior plate through which the control of the blank forming is realized.
Abstract: In this work the authors present some results of their research activity aimed to enhance the sheet hydroforming process. The main focus is the adoption of a movable inferior plate through which the control of the blank forming is realised. Tests on hemitoroidal parts using an innovative equipment with a movable die were carried on at the Institute of Metal Research (Chinese Academy of Sciences) in cooperation with the Aalborg University, putting in evidence main defects and fracture causes. Finite element simulations of the modified hydroforming process using a movable inferior plate were performed at the Centre of Excellence for Mechanical Computation (Polytechnic of Bari), with the aim of evaluating critical strain values and their location, strain paths, load curves and stress maps were analysed. Specimens with proper geometrical shape were designed to avoid possible ruptures and to reduce material thinning in the critical regions.

Journal ArticleDOI
TL;DR: In this article, a simplified and applied tooling was designed for charactering the material formability in tube hydroforming (THF) process and the quality of the deformed tube.

Journal ArticleDOI
TL;DR: In this paper, a review of the aluminum alloys hydroforming and the simulation via FEM of two-hydroforming process is made: for the first simulation, the hydroforming of a free aluminum tube without axial force and for the second one, the study of a tube in a die.

Book ChapterDOI
01 Jan 2006
TL;DR: In this paper, the authors present the forces analysis in relation to the tool path and its diameter and individualization of the points where failure conditions take place by simple evaluation of the reach stress values.
Abstract: Publisher Summary This chapter characterizes innovative techniques, such as hydroforming and incremental forming by the possibility to be easily adapted to realize a small production lot with low tools cost. The chapter discusses grooves in sheets, which have been realized by means of the incremental forming technology. It presents the forces analysis in relation to the tool path and its diameter. FEM simulations are achieved with the purpose to carry out a comparison between the forces values experimentally pointed out and the ones by FEM. FE analysis also allows the individualization of the points where failure conditions take place by simple evaluation of the reach stress values. Therefore, the FE method can be used to determine the tool path in the design phase of the process cycle.


Journal ArticleDOI
TL;DR: In this article, an active-elastic blank holder for high-pressure forming of metal sheets is described, which shows improvements with respect to the material flow in the flange area and reduced sheet thinning.
Abstract: Hydroforming constitutes a subgroup of sheet metal forming processes utilizing a pressurized forming medium. Besides the hydroforming of hollow sections, the high-pressure forming (HPF) of metal sheets is demonstrably one innovative method for the production of complex sheet metal components and offers high potentials to improve the properties and qualities of sheet metal parts. This report describes investigations of a newly developed active-elastic blank holder technology, which is used for HPF of metal sheets. Unlike the use of semi-rigid blank holder systems, the active-elastic blank holder system shows improvements with respect to the material flow in the flange area and reduced sheet thinning in critical corner regions of the work-piece. In addition to numerical analysis concerning the development and design of the active-elastic blank holder, current experimental examinations will be presented. The focus is on a comparative evaluation of the simulation and production of rectangular metal parts, by using conventional semi-rigid tools and active-elastic tools.

Journal ArticleDOI
TL;DR: In this paper, a computationally efficient direct design method, which effectively improves the design procedure, was introduced, which was successfully applied for the design of flat blanks for stamping processes.

Patent
Igor Riff1, Michael T. Costello1
04 Apr 2006
TL;DR: In this article, a method for improving lubricants employed in hydroforming processes is disclosed wherein said method comprises adding to said lubricants at least one over-based detergent and at least friction modifier.
Abstract: A method for improving lubricants employed in hydroforming processes is disclosed wherein said method comprises adding to said lubricants at least one overbased detergent and at least one friction modifier.

Journal ArticleDOI
TL;DR: In this article, an optimization procedure involving a determination of the hydroforming pressure through an incremental step-by-step optimization scheme is proposed, and a control loop running the overall process based on the adjustment of the volume of fluid in the inner tube cavity is proposed.

Journal ArticleDOI
TL;DR: In this paper, the effects of textured tubes on the tribological performance in tube hydroforming were discussed, and it was shown that the increase in the interface pressure between the tube and the die can result in either lower or higher interface friction depending on the surface texture conditions.
Abstract: The effects of textured tubes on the tribological performance in tube hydroforming (THF) are discussed. Textured surfaces, namely sand blasted, knurled, electrical discharge machined (EDM), and as rolled surfaces, were tested under various interface pressure conditions. Sand blasted textured tubes were found to have the best tribological performance. The study has demonstrated that the increase in the interface pressure between the tube and the die can result in either lower or higher interface friction depending on the surface texture conditions. The study has also shown that different surface texture treatment methods can alter the hardness of the tube surface with significant influence on the tribological performance.