Buckling of Tube for Tube Hydroforging

2019 ◽  
Author(s):  
Chetan P. Nikhare
Keyword(s):  
Axial Force ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Expansion Ratio ◽  
Rigid Bodies ◽  
Maximum Expansion ◽  
Tube Forming ◽  
Strain Pattern ◽  
Hydroforming Process

Abstract Tube forming is one of the most common manufacturing processes to shape the tubes. Within tube forming operations the general practice is to expand and reduce the tube end cross-section and bend the tube by means of a solid mandrel. Mostly the mandrel is rigid bodies. To reduce the friction between the tube and the tool, tube hydroforming process was evolved in which the fluid was highly pressurized to expand the tube shape to the desired shape. By reducing the friction more uniform thickness could be achieved and thus increase in formability. In this paper, the tube was formed in two steps with low fluid pressure and axial force. The tube will be allowed to a useful maximum buckle by applying the axial force and/or a ramp internal pressure which then hydroforged with constant pressure for the maximum expansion ratio. The buckling mechanics of tube with respect to the fluid pressure and the axial force was studied. Further, the pressure requirement for hydroforging was investigated with respect to the length of the tube. The strain pattern and thickness distribution were studied in the buckling/bulging and hydroforging step.

Tube Buckling: An Advantage to Tube Shaping

2018 ◽  
Author(s):  
Chetan P. Nikhare
Keyword(s):  
Tube Hydroforming ◽  
Rigid Bodies ◽  
Outer Diameter ◽  
Forming Process ◽  
Tube Forming ◽  
Strength Coefficient ◽  
Tube Shape ◽  
Tube Flaring ◽  
Hydroforming Process ◽  
Proper Consideration

Tube forming is one of the most common manufacturing processes to shape the tubes. Within tube forming operations the general practice is to expand and reduce the tube end cross-section and bend the tube by means of a solid mandrel. Mostly the mandrel is rigid bodies. To reduce the friction between the tube and the tool, tube hydroforming process was evolved in which the fluid was highly pressurized to expand the tube shape to the desired shape. By reducing the friction more uniform thickness could be achieved and thus increase in formability. One of the process within tube end forming process is flaring which is the focus of this paper. In tube flaring process the conical shape rigid tool flares the end of the tube. While flaring the tube, the tube buckles if proper consideration would not have been taken. In this paper, various influencing parameters such as outer diameter to tube thickness ratio, length or the tube, the strength coefficient of the tube and conical angle of the tool were analyzed. It was noted that the most important factor affect the buckling of the tube is its strength coefficient. Considering this parameter the buckling was carried out in a set die and a tube shape was formed. The advantages of this process over similar processes were discussed.

Die Design and Axial Feeding in the Tube-Hydroforming Process

2010 ◽  
Author(s):  
Sin-Liang Lin ◽  
Fuh-Kuo Chen
Keyword(s):  
Finite Element ◽  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Expansion Ratio ◽  
Loading Path ◽  
Structural Part ◽  
Axial Feeding ◽  
Internal Fluid ◽  
Hydroforming Process ◽  
Production Part

In the present study, the loading path with constant internal fluid pressure during axial feeding to hydroform an automotive structural part with higher expansion ratio was investigated. The axial feedings employed at various internal fluid pressures were simulated by the finite element method. It is found that the axial feeding applied at a favorable internal fluid pressure, the production part with higher expansion ratio still could be made. Compared with other loading paths published in literature, which are mainly linear paths, the proposed loading path provides a simple approach to achieve better performance in the hydroforming process. The factors causing wrinkling fin the hydroforming process were also studied by analyzing the relationship between the die face shape and the material flow in the die cavity. An optimum die face design that avoided pinching at the die closing process was then proposed. The actual hydroforming process for manufacturing the automotive structural part was conducted as well in the present study to validate the proposed loading path and the optimum die face design. The consistent agreement between the production part and the finite element simulation results confirms not only the proposed loading path and die face design, but also the effectiveness of the finite element analysis employed in the tube-hydroforming process.

Optimization of Tube Hydroforming Process Using Probabilistic Constraints on Failure Modes

2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami
Keyword(s):  
Failure Modes ◽  
High Reliability ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Plastic Instability ◽  
Probabilistic Constraints ◽  
Forming Limit ◽  
Reliability Based Design ◽  
Hydroforming Process

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.

A Critical Review of Tube and Sheet Metal Hydroforming Technology

1996 ◽  
Author(s):  
Jian An ◽  
A. H. Soni
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Point Of View ◽  
Parameter Design ◽  
Back Side ◽  
Part Quality ◽  
Element Simulation ◽  
Part Surface ◽  
Hydroforming Process

Abstract The hydroforming technology, which is rapidly gaining popularity in the sheet metal and tube forming industry is reviewed. The features and the characteristics of the hydroforming process are described. The uniformly distributed fluid pressure covers the back side of the sheet as a die generates many advantages in the technical point of view as improving the part surface quality, reducing the forming severity and smoothing the thickness distribution. The benefits of using hydroforming technology are examined and analyzed in a technical level. The better part quality, less cost of tooling, materials saving and part weight reduction can be achieved using the hydroforming technology. The design methodologies for the hydroforming process parameters are reviewed and discussed in a certain detail. Computer-aided-engineering such as finite element simulation is suggested for such process parameter design.

Tube Hydroforming (THF): Process Optimization of an Automotive Component

2013 ◽  
Vol 549 ◽  
pp. 141-148
Author(s):  
Aldo Attanasio ◽  
Elisabetta Ceretti ◽  
Giancarlo Maccarini
Keyword(s):  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Experimental Tests ◽  
Side Impact ◽  
Pressure Curve ◽  
Part Geometry ◽  
Italian Government ◽  
Working Solution ◽  
Hydroforming Process ◽  
Good Agreement

This paper reports the results obtained during a research project funded by the Italian Government and involving several Italian Universities (PRIN INTEMA). The activities have been focused on side impact bar manufacturing by means of Tube Hydroforming process (THF). Punch movement paths and fluid pressure curve were optimized by means of FEM software (LS-DYNA) to guarantee tube sealing and material feeding during the tube deformation. The side impact bar geometry was optimized till reaching the shape guaranteeing the obtainment of safe parts with the best compromise in terms of final part geometry and thickness reduction. Different fluid pressure and punch movement paths were investigated. Once accomplished all the simulations and identified the best working solution, experimental tests were performed setting the process parameters according to the values defined during the simulation phase. Good agreement between FEM and experimental results were highlighted.

Numerical and Experimental Study of the Effect Pressure Path in Tube Hydroforming Process

2011 ◽  
Vol 473 ◽  
pp. 579-586
Author(s):  
Majid Elyasi ◽  
Hassan Khanlari ◽  
Mohammad Bakhshi-Jooybari
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Stainless Steel ◽  
Experimental Approach ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Initial Pressure ◽  
Low Carbon ◽  
Element Simulation ◽  
Hydroforming Process

In this paper, the effect of pressure path on thickness distribution and product geometry in the tube hydroforming process is studied by finite element simulation and experimental approach. In simulations and experiments, low carbon stainless steel (SS316L) seamless tubes were used. The obtained results indicated that with increasing of the initial pressure, the bulge value of the part increases and the wrinkling value decreases. In addition, if the initial pressure is highly decreased, then bursting may occur.

FE Simulation and Experimental Study of Tube Hydroforming Process for AA1050 Alloy at Various Temperatures

2011 ◽  
Vol 264-265 ◽  
pp. 96-101
Author(s):  
Hassan Moslemi Naeini ◽  
Golam Hosein Liaghat ◽  
S.J. Hashemi Ghiri ◽  
S.M.H. Seyedkashi
Keyword(s):  
Elevated Temperatures ◽  
New Technologies ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Thermal Conditions ◽  
High Strength ◽  
Different Temperatures ◽  
Hydroforming Process ◽  
Production Technologies ◽  
Advanced Production

Considering the necessity of using light weight, high strength and corrosion resistant materials, automotive and aerospace industries need to use advanced production technologies. Hydroforming has been regarded as one of the new technologies in forming of aluminium and magnesium alloys. These alloys have very low formability at room temperature which will be improved at elevated temperatures. In this paper, AA1050 aluminium alloy tube is numerically and experimentally investigated at different temperatures. Thickness distribution in forming zone is studied under different thermal conditions. Numerical results have been verified by experiments and there is a good agreement.

Two Dimensional Plane Strain Modeling of Tube Hydroforming

2000 ◽  
Author(s):  
G. T. Kridli ◽  
L. Bao ◽  
P. K. Mallick
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Material Properties ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Strain Hardening Exponent ◽  
Hydraulic Pressure ◽  
Two Dimensional ◽  
Dimensional Plane ◽  
Hydroforming Process

Abstract The tube hydroforming process has been used in industry for several years to produce components such as exhaust manifolds. Recent advances in forming machines and machine control systems have allowed for the introduction and the implementation of the process to produce several automotive components, which were originally produced by the stamping process. Components such as side rails, engine cradles, space frames, and several others can be economically produced by tube hydroforming. The process involves forming a straight or a pre-bent tube into a die cavity using internal hydraulic pressure, which may be coupled with controlled axial feeding of the tube. One of the remaining challenges facing product and process engineers in designing hydroformed parts is the lack of an extensive knowledge base of the process. This includes a full understanding of the process mechanics and the effects of the material properties on the quality of the hydroformed product. This paper reports on the results of two dimensional plane strain finite element models of the tube hydroforming process, which were conducted using the commercial finite element code ABAQUS/Standard. The objective of the study is to examine the effects of material properties, die geometry, and frictional characteristics on the selection of the hydroforming process parameters. The paper discusses the effects of the strain-hardening exponent, friction coefficient at the die-workpiece interface, initial tube wall thickness, and die corner radii on the thickness distribution of the hydroformed tube.

Numerical – Experimental Correlation of Sheet Hydroformed Component

2015 ◽  
Vol 651-653 ◽  
pp. 1140-1145
Author(s):  
Alessandro Spagnolo ◽  
Teresa Primo ◽  
Gabriele Papadia ◽  
Antonio del Prete
Keyword(s):  
Finite Element ◽  
Process Parameters ◽  
Complex Geometry ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Experimental Tests ◽  
Element Analysis ◽  
Influence Of Process Parameters ◽  
Experimental Correlation ◽  
Hydroforming Process

Sheet hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as higher forming potentiality, good quality of the formed parts which may have complex geometry. The main advantage is that the uniform pressure can be transferred to any part of the formed blank at the same time. This paper reports numerical and experimental correlation for symmetrical hydroformed component. Experimental tests have been carried out through the hydroforming cell tooling, designed by the authors thanks to a research project, characterized by a variable upper blankholder load of eight different hydraulic actuators. The experimental tests have been carried out following a factorial plane of two factors, with two different levels for each factor and three replicates for each test with a total of 12 tests. In particular two process parameters have been considered: blank holder force, die fluid pressure. Each factor has been varied between an High (H) and Low level (L). The order in which have been conducted the tests has been established through the use of the Minitab software, in order to ensure the data normality and the absence of auto-correlation between the tests. An ANOVA analysis has been performed, in addition, with the aim of evaluating the influence of process parameters on the thickness distribution of the component, its formability and feasibility. Finally, finite element analysis (FEA) was used to understand the formability of a material during the hydroforming process. In this paper, the commercial finite element code LS-Dyna was used to run the simulations. A good numerical – experimental correlation has been obtained.

Investigation of Load Path Effect on Thickness Distribution and Product Geometry in the Bulge Hydroforming Process

2011 ◽  
Vol 110-116 ◽  
pp. 1477-1482 ◽  
Author(s):  
Majid Elyasi ◽  
Hassan Khanlari ◽  
Mohammad Bakhshi-Jooybari
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Simulation ◽  
Experimental Approach ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Low Carbon ◽  
Load Path ◽  
Element Simulation ◽  
Hydroforming Process

In this paper, the effect of load path on thickness distribution and product geometry in the tube hydroforming process is studied by finite element simulation and experimental approach. The pressure path was obtained by using finite element simulation and its validation with experiments. In simulations and experiments, low carbon stainless steel (SS316L) seamless tubes were used. The obtained results indicated that if pressure reaches to maximum faster, bulge value and thinning of the part will be more and wrinkling value will be less.

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