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Showing papers on "Hydroforming published in 2011"


Journal ArticleDOI
TL;DR: In this article, different approaches for the analysis of hydraulic bulge were compared with experimental results to determine the best combination in obtaining accurate flow curves models at room and elevated temperature conditions for different lightweight materials of interest for several industrial applications.

117 citations


Journal ArticleDOI
TL;DR: In this article, metallic bipolar plate (BPP) samples manufactured with stamping and hydroforming under different process conditions were tested for their electrical contact resistance characteristics to reveal the effect of manufacturing type and conditions.

60 citations


Journal ArticleDOI
TL;DR: In this paper, a finite element study along with response surface methodology (RSM) for design of experiment (DOE) has been used to construct models for three responses namely: bulge height, thickness reduction, and wrinkle height as a function of geometrical factors for X shape bi-layered tube hydroforming.

57 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented a simulation of free hydroforming of aluminum alloy tubes with axial feeding and showed that a shell element model was able to capture the majority of the structural features of the process very successfully.

43 citations


Journal ArticleDOI
TL;DR: The bulge height and the wall thickness reduction of the bi-layered hydroformed parts (responses) are modelled as functions of the geometrical factors using the combination of the finite element modelling (FEM) and Response Surface Methodology (RSM) for design of experiments (DOE).

42 citations


Journal ArticleDOI
Xianfeng Chen1, Zhongqi Yu1, Bo Hou1, Shuhui Li1, Zhongqin Lin1 
TL;DR: In this article, a new theoretical model is developed to predict the forming limit diagram (FLD) for a seamed tube hydroforming, which is based on the Hosford yield criterion.

31 citations


Journal ArticleDOI
TL;DR: In this article, a 2D numerical model was used to optimize the loading histories of aluminum tubes, and their performance in predicting all aspects of the experimental results were discussed in Part II.

31 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated and optimized the forming parameters of tube hydroforming (THF) process using a Simulated Annealing optimization algorithm linked with a finite element commercial code and obtained the maximum formability of axisymmetric tubes under a failure criteria based on material's forming limit diagram.

29 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used the analysis of variance (ANOVA) technique to determine the statistical significance of the corrosion resistance differences between different manufacturing conditions, and then they used this technique to obtain the corrosion current density (Icorr, μA-cm−2) values obtained from experiments.

28 citations


Journal ArticleDOI
TL;DR: It was found that the final bulges heights resulted from the models were in good agreement with the experimental results when numerically simulated using the finite element method.

27 citations


Journal ArticleDOI
TL;DR: In this paper, a comparison of numerical results and experimental measurements obtained from closed-die forming, hydraulic bulge and tensile tests at different temperature (25 − 300 °C) and strain rate (0.0013 − 0.013 1/sec) levels were taken as comparison parameters.

Journal ArticleDOI
TL;DR: In this article, the feasibility of the use of disposable actuators during electromagnetic forming of two aluminum components was discussed, a very simple part with a one-dimensional curve and a realistic part whose main feature is a convex flange with two joggles.

Journal ArticleDOI
TL;DR: In this article, a new method of sheet hydroforming assisted by floating disk is proposed and investigated through experiments and simulation, and its advantages, such as simplifying the tools, decreasing the required medium pressure of the forming process, and elimination of some wrinkle due to ironing effect, have been discussed.
Abstract: A simplified sheet hydroforming tooling was designed, fabricated, and tested. The advantage of the new tooling is its simplification of the tools, its requirement of lower hydraulic pressure for forming and decreasing the cost of the process. In this article, a new method of hydroforming deep drawing assisted by floating disk is proposed and investigated through experiments and simulation. Moreover, its advantages, such as simplifying the tools, decreasing the required medium pressure of the forming process, and elimination of some wrinkle due to ironing effect, have been discussed. An aluminum alloy, Al6061-T6, is formed successfully, and the influence of process parameters including the punch nose radius and friction are studied. It is determined that decreasing punch radii and friction, lead to a decrease in initial pressure and an increased safe zone, respectively. Working pressure curves, which guarantee sound workpieces, have been founded by series of experimental results. Wrinkling and fracture mod...

Journal ArticleDOI
TL;DR: In this article, the formability of Ti6Al4V titanium alloy and Al6061-T6 aluminum alloy sheets is investigated experimentally using hydroforming deep drawing and Artificial Neural Network (ANN) modeling of the process based on experimental results is introduced to predict FLDs.
Abstract: Forming limit diagram (FLD) provides the limiting strains a sheet metal can sustain whilst being formed. In this article, the formability of Ti6Al4 V titanium alloy and Al6061-T6 aluminum alloy sheets is investigated experimentally using hydroforming deep drawing. Hecker's simplified technique [1] was used to obtain experimental FLDs for these sheet materials. Artificial neural network (ANN) modeling of the process based on experimental results is introduced to predict FLDs. It is shown that a feed forward back propagation (BP) ANN can predict the FLDs, therefore, indicating the possibility of ANN as a strong tool in simulating the process. According to comparisons there is a good agreement between experimental and neural network results.

Journal ArticleDOI
TL;DR: In this paper, the optimal process conditions were evaluated to determine the robustness and process capability based on physical measurement of formed parts including thickness strain, cavity fill ratio, and radius of curvature.
Abstract: The warm sheet hydroforming process was investigated to determine the optimal process conditions of temperature, pressure, and pressurization rate for maximum formability of AA5754-O using an experimental stretch forming die shape. The optimal process conditions were evaluated to determine the robustness and process capability based on physical measurement of formed parts including thickness strain, cavity fill ratio, and radius of curvature. For the simple die shape investigated, a temperature of 268°C, a pressure of 25 MPa, and a pressurization rate of 0.22 MPa/s provided the most balanced combination of uniform thickness strain with the greatest cavity fill ratio and sharpest radius. Temperature had a greater effect on measured properties than either pressure or pressurization rate, although the effect of pressure increased as temperature decreased. The procedures demonstrated in this experimental study could be used to optimize process parameters for robust operation of production applications for more complex automotive body panels fabricated by the warm hydroforming process.

Journal ArticleDOI
TL;DR: In this paper, a modification made to the classical tube drawing process, the sinking and fixed-mandrel tube drawing methods were mixed together to produce tubes with variable thickness in the axial direction.

Patent
19 Jul 2011
TL;DR: In this paper, a hydroforming die assembly for deforming a tube and a method for deformation the tube are provided, as well as a method to deform the tube.
Abstract: A hydroforming die assembly for deforming a tube and a method for deforming the tube are provided.

Journal ArticleDOI
TL;DR: In this article, the friction coefficient between tube and die in guide zone of tube hydroforming was obtained, where the tube is expanded by an internal pressure against the tool wall and a friction force at the contact surface between the tube and the tool occurs.

Journal ArticleDOI
TL;DR: In this paper, a sheet hydroforming process (SHF) was adopted to improve the formability of Ti/Al clad metal sheets and SUS 304 metal sheets used in computer, communication, and consumer product housings.
Abstract: Clad metals are becoming increasingly emphasized in sheet metal applications. In this research, sheet hydroforming process (SHF) was adopted to improve the formability of Ti/Al clad metal sheets and SUS 304 metal sheets used in computer, communication, and consumer product housings. Both finite element simulation and experimental verification were carried out to investigate the deformation of blanks. Several significant process parameters, such as holding force, friction, counter pressure history, and blank dimensions, were discussed for improving the formability of the two metal sheets. In SHF simulation, a virtual film technique was proposed to realistically approach the hydraulic loading condition during SHF. Finally, the deformed shape and thickness distribution of parts manufactured with SHF were compared with the results of simulation. Good agreements were obtained.

Journal ArticleDOI
TL;DR: In this article, the authors presented a virtual simulation of the hoses hydroforming; the main objective is to predict when and where cracks can appear during a cyclic loading, and a methodology has been proposed to investigate the effects of plastic strain and residual stress after hydroforming on cyclic life fatigue.

Journal ArticleDOI
TL;DR: In this paper, a limit liquid pressure corresponding to different clamping forces was calculated theoretically, which can be used to reveal the influence of process parameters combination on deformation behaviors, and the calculated results were studied and verified by FE analysis and experiments.

Journal ArticleDOI
TL;DR: In this article, the deformation mode and the process were analyzed during hydromechanical deep drawing of aluminum alloy complex-shaped components with a doubly curved surface, formed by conventional deep drawing and drop stamping, and the results showed that the reasonable chamber pressure to avoid the above defects is 10-30 MPa.

Journal ArticleDOI
TL;DR: In this paper, the authors developed an interactive real-time database that can predict loading paths for many tube hydroforming components and hence reduce the computational time required by using multidimensional cubic spline interpolation.

Journal ArticleDOI
TL;DR: A finite element model was established for bi-layered tube hydroforming process using ANSYS LS- DYNA pre-processor and LS-DYNA solver in order to predict the most efficient and acceptable operating condition for certain material properties and initial blank geometry.

Patent
29 Jun 2011
TL;DR: In this article, a method for forming thin-walled parts through stamping and drawing, which is used for reducing the thicknesses of raw materials to 50-100% of the original thicknesses the raw materials, was disclosed.
Abstract: The invention discloses a method for forming thin-walled parts through stamping and drawing, which is used for reducing the thicknesses (0.4-2mm) of raw materials to 50-100% of the original thicknesses the raw materials; the raw materials comprise magnesium alloys, aluminum alloys, titanium alloys, high temperature alloys and complex splice-welded plates; and the method specifically comprises the following steps that: a flexible forming technique is adopted with the aid of moulds and a hydraulic machine, wherein the moulds are in concave-convex fit with the hydraulic machine; upper and lower blank holders and concave and convex moulds are respectively subjected to hydraulic pressure exertion control; the nominal pressure of a main hydraulic cylinder exerted on the concave and convex moulds is 25000-4500 KN, and the nominal pressure of a side-pressing hydraulic cylinder accounts for 50-67% of the nominal pressure of the main hydraulic cylinder; and the maximum operating pressure of a liquid chamber is 150MPa. By using the method disclosed by the invention, an expected effect is obtained, and the qualification rates and efficiencies of parts are obviously improved; and meanwhile, the hydroforming technology fills in the gaps in industry application, and lays a solid foundation for the thorough solving of technical bottlenecks existing in actuating cylinder cover forming and the research and preparation of future novel thin-wall parts and sheet metal forming parts.

Journal Article
TL;DR: The concept of limited corner radius in calibration process was proposed and analyzed in this article, and the concept of ring hoop tension test was proposed to evaluate the mechanical properties of tube along hoop direction, and double-layered hydro-bending method for the forming of thin-walled bent tubular part was proposed.
Abstract: Important progresses and achievements in fundamental theory,key processes and industrial applications of tube hydroforming realized in engineering research center of hydroforming/harbin institute of technology(ERCH/HIT) were introducedTypical stress states in tube hydroforming process and the corresponding thickness changing tendency were given on the plane stress yield lociThickness changes along the axial direction of tubular part with changeable diameters and the hoop direction of tubular part with rectangular cross-section were givenThe concept of limited corner radius in calibration process was proposed and analyzedRing hoop tension test was proposed to evaluate the mechanical properties of tube along hoop directionMulti-step method for the forming of thin Y-shaped branch tube,and double-layered hydro-bending method for the forming of thin-walled bent tubular part were proposedUltra-thin Y-shaped branch tube,integral stainless steel tube,and bent tubular part for aerospace application were manufacturedHydroforming machine of 55 MN maximal closing force was developedTypical parts for automotive industry,such as engine cradle,front beam holder and torsion beam,were manufactured


Journal ArticleDOI
TL;DR: In this article, the force and power requirements for air bending of structured sheet metals are calculated with a Finite Element Simulation (FE) and an analytical approach, and the results of the FE-Simulation, the analytic calculation and the experiments are compared.
Abstract: Structured sheet metals with regular bumps offer higher stiffness compared to smooth sheet metals. They can be produced by a hydroforming process. The application of the structured sheet metals, however, is inhibited by the lack of knowledge for the subsequent processing steps. In this paper, the force and power requirements for air bending of structured sheet metals are calculated with a Finite Element Simulation (FE) and an analytical approach. In the first step, the hydroforming manufacturing process of the structured sheet metals is simulated in order to predict the exact geometry and the change in the material properties. Following, air bending simulations have been done taking into account the results of the hydroforming simulation. The FE-Simulations have been carried out with the software package LS-DYNA. The simulation models are validated with the optical displacement measuring system ARGUS and by a series of bending tests. For the analytical calculation the model based on the bending theory is adapted by simplifying the cross section of the structured sheet metals. The results of the FE-Simulation, the analytic calculation and the experiments are compared. The advantages and disadvantages as well as the application areas of the considered methods are indicated.

Journal ArticleDOI
TL;DR: In this article, the deformation characteristics of three common austenitic stainless steels (AISI 201, 301, and 304) were investigated using closed-die hydroforming under different process conditions.
Abstract: Stainless steel sheet alloys have been increasingly used in heating, ventilating, and air conditioning; appliance; sanitary and medical devices; as well as several structural and transportation applications, due to their high strength-to-weight ratio, corrosion resistance, biomedical compatibility, and esthetic appearance. Among various stainless steel alloys, austenitic stainless steels are the most commonly used type. Due to the forming limitations into complex shapes at room temperature conditions and stress-corrosion cracking issues, forming at elevated temperature has been considered as an enabling technique. Formability of stainless steels is affected by strain rate and temperature due to martensitic transformation of meta-stable austenite microstructure. In this study, deformation characteristics of three common austenitic stainless steels (AISI 201, 301, and 304) were investigated using closed-die hydroforming under different process conditions. Specifically, effects of pressure, temperature, and die/part geometry on the material forming characteristics quantified using cavity filling ratio and thinning distribution were investigated. Results suggested that, in terms of cavity filling, pressure and material grade are significant factors while temperature is not in the case of axisymmetric part. For the non-axisymmetric case, all parameters were found to be significant. In addition, finite element (FE) modeling was performed to simulate several forming cases that were experimentally conducted in this study. The FE model was simulated based on material flow curves obtained from previous studies under similar conditions (strain rate and temperature) by the authors. FEA results were shown to be in good agreement with experimental findings, particularly for cavity filling and part profile predictions. Hence, the FE model and the material models can be used for further predictions of complex and different parts with confidence.

Proceedings ArticleDOI
29 Aug 2011
TL;DR: In this paper, a finite element simulation of the sheet hydroforming with punch (SHF•P) process for AA5754•O sheet is presented. But, there is limited experience-based knowledge of process parameter selection and tool design for SHF-P of these materials.
Abstract: The sheet hydroforming with punch (SHF‐P) process offers great potential for low and medium volume production, especially for forming: (1) lightweight sheet materials such as aluminum (Al) and magnesium (Mg) alloys and (2) thin gage high strength steels (HSS). Mg and Al alloys are being increasingly considered for automotive applications, primarily due to their lightweight and high strength‐to‐weight ratios. However, there is limited experience‐based knowledge of process parameter selection and tool design for SHF‐P of these materials. Thus, there is a need for a fundamental understanding of the influence of process parameters on part quality. This paper summarizes analyses of the SHF‐P process of AA5754‐O sheet using finite element (FE) simulations. FE simulations and preliminary experiments of SHF‐P were conducted to determine the process parameters (blank holder force versus punch stroke and pot pressure versus stroke) to form a challenging shape (a cylindrical cup with a reverse bulge) successfully at...