Study of Localized Thinning of Copper Tube Hydroforming in Square Section Die: Effect of Friction Conditions

2015 ◽  
Vol 651-653 ◽  
pp. 65-70 ◽  
Author(s):  
Abir Abdelkefi ◽  
Nathalie Boudeau ◽  
Pierrick Malecot ◽  
Noamen Guermazi ◽  
Gérard Michel
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Analytical Model ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Analytical Models ◽  
Specific Test ◽  
Good Evaluation ◽  
Shaped Tube ◽  
Tube Expansion

The friction conditions are responsible of the thickness distribution in a part realized by tube hydroforming. Then it is essential to have a good evaluation of the friction coefficient for running predictive finite element simulations. The tube expansion in a square die is one of tests proposed for the friction evaluation. In the literature, several analytical models have been developed for this specific test. The present paper concentrates on one of this model and results obtained from the analytical analysis, FE simulations and experiments are compared. The repartition of the thickness over the shaped tube and its evolution during the process are studied. The tendencies are in agreement but some complementary evaluations are proposed for using the proposed approach for the evaluation of the friction coefficient with the analytical model.

scholarly journals On the Friction Effect on the Characteristics of Hydroformed Tube in a Square Section Die: Analytical, Numerical and Experimental Approaches

2015 ◽  
Vol 639 ◽  
pp. 83-90 ◽  
Author(s):  
Abir Abdelkefi ◽  
Nathalie Boudeau ◽  
Pierrick Malecot ◽  
Gérard Michel ◽  
Noamen Guermazi
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Friction Condition ◽  
Minimal Thickness ◽  
Straight Wall ◽  
Experimental Approaches ◽  
Hydroformed Tube ◽  
Corner Filling

A focus on the effect of friction condition on tube hydroforming during corner filling in a square section die is proposed. Three approaches have been developed: an analytical model from the literature has been programmed, finite element simulations have been conducted and experiments have been carried out. Effect of friction coefficient on the thickness distribution in the square section of the hydroformed tube is studied. Critical thinning is found to take place in the transition zone between the straight wall and the corner radius and this minimal thickness seems to be the more appropriate parameter for the evaluation of the friction coefficient.

Adaptive Simulations of T-Shape Tube Hydroforming Processes

2007 ◽  
Vol 340-341 ◽  
pp. 627-632 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Bing Hong Chen ◽  
Wen Chan Chang
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Adaptive Algorithm ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Loading Path ◽  
Finite Element Code ◽  
Simulation Results ◽  
Formed Product ◽  
The Relationship

A successful THF process depends largely on the loading paths for controlling the relationship between the internal pressure, axial feeding and the counter punch. In this study, an adaptive algorithm combined with a finite element code LS-DYNA 3D is proposed to control the simulation of T-shape hydroforming with a counter punch. The effects of the friction coefficients at the interface between the tube and die on the loading path and thickness distribution of the formed product are discussed. Experiments of protrusion hydroforming are also conducted. The final shape and thickness distribution of the formed product are compared with the simulation results to verify the validity of this modeling.

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.

A Combined Analytical and Numerical Approach to Analyze Mud Motor Excited Vibrations in Drilling Systems

2015 ◽  
Author(s):  
Andreas Hohl ◽  
Carsten Hohl ◽  
Christian Herbig
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Field Measurements ◽  
Element Model ◽  
Numerical Approach ◽  
Analytical Models ◽  
Finite Element Models ◽  
Beam Model ◽  
Direct Influence ◽  
Practical Applications

Severe vibrations in drillstrings and bottomhole assemblies can be caused by cutting forces at the bit or mass imbalances in downhole tools. One of the largest imbalances is related to the working principle of the so-called mud motor, which is an assembly of a rotor that is maintained by the stator. One of the design-related problems is how to minimize vibrations excited by the mud motor. Simulation tools using specialized finite element methods (FEM) are established to model the mechanical behavior of the structure. Although finite element models are useful for estimating rotor dynamic behavior and dynamic stresses of entire drilling systems they do not give direct insight how parameters affect amplitudes and stresses. Analytical models show the direct influence of parameters and give qualitative solutions of design related decisions. However these models do not provide quantitative numbers for complicated geometries. An analytical beam model of the mud motor is derived to calculate the vibrational amplitudes and capture basic dynamic effects. The model shows the direct influence of parameters of the mud motor related to the geometry, material properties and fluid properties. The analytical model is compared to the corresponding finite element model. Vibrational amplitudes are discussed for different modes and parameter changes. Finite element models of the entire drilling system are used to verify the findings from the analytical model using practical applications. The results are compared to time domain and statistical data from laboratory and field measurements.

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.

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.

Investigation on the Effect of Pulsating Pressure on Tube-Hydroforming Process

2011 ◽  
Vol 473 ◽  
pp. 618-623
Author(s):  
Khalil Khalili ◽  
Seyed Yousef Ahmadi-Brooghani ◽  
Amir Ashrafi
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Element Model ◽  
Fe Model ◽  
Axial Feeding ◽  
Hydroforming Process ◽  
The Finite Element Model ◽  
Good Agreement

Tube hydroforming process is one of the metal forming processes which uses internal pressure and axial feeding simultaneously to form a tube into the die cavity shape. This process has some advantages such as weight reduction, more strength and better integration of produced parts. In this study, T-shape tube hydroforming was analyzed by experimental and finite element methods. In Experimental method the pulsating pressure technique without counterpunch was used; so that the internal pressure was increased up to a maximum, the axial feeding was then stopped. Consequently, the pressure decreased to a minimum. The sequence was repeated until the part formed to its final shape. The finite element model was also established to compare the experimental results with the FE model. It is shown that the pulsating pressure improves the process in terms of maximum protrusion height obtained. Counterpunch was eliminated as being unnecessary. The results of simulation including thickness distribution and protrusion height were compared to the part produced experimentally. The result of modeling is in good agreement with the experiment. The paper describes the methodology and gives the results of both experiment and modeling.

Tube Hydroforming of Magnesium Alloys at Elevated Temperatures

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Yan-Huang Su ◽  
Bing-Jian Chen
Keyword(s):  
Finite Element ◽  
Elevated Temperatures ◽  
Flow Line ◽  
Thickness Distribution ◽  
Testing Machine ◽  
Tube Hydroforming ◽  
Axial Feeding ◽  
Forming Temperature ◽  
Formed Product ◽  
Deform 3D

In this paper, a hydraulic forming machine with the functions of axial feeding, counter punch, and internal pressurization is designed and developed. This self-designed forming machine has a capacity of 50 tons for axial feeding and counter punch, 70 MPa for internal pressurization, and 300°C for forming temperature. Using this testing machine, experiments of T-shape protrusion of magnesium alloy AZ61 tubes at elevated temperatures are carried out. A commercial finite element code DEFORM 3D is used to simulate the plastic deformation of the tube within the die during the T-shape protrusion process. Different kinds of loading paths for the pressurization profile and the strokes of the axial feeding and the counterpunch are scheduled for analyses and experiments of protrusion processes at 150°C and 250°C. The numerical thickness distributions and the flow line configurations of the formed product are compared with the experimental results to validate this finite element modeling. The thickness distribution of the formed product or the flowability of AZ61 tubes at 150°C and 250°C is discussed. The effects of the forming rate on tube flowability at 250°C are also investigated. Through the observation of the flow line configurations of the tube material, adequate backward speeds of the counter punch relative to the axial feeding for preventing the material from accumulating at the die entrance region are verified. Finally, a sound product with a protrusion height of 49 mm is obtained.

Some Further Studies on the Axial–Torsional Behavior of Flexible Risers

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Roberto Ramos ◽  
Clóvis A. Martins ◽  
Celso P. Pesce ◽  
Francisco E. Roveri
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Experimental Tests ◽  
Analytical Models ◽  
Analysis Tool ◽  
Full Data ◽  
Technical Literature ◽  
External Pressures ◽  
Flexible Risers ◽  
Ocean Environment

Flexible risers are complex structures composed of several concentric polymeric and steel armor layers that withstand static and dynamic loads applied by the floating production vessel and by the ocean environment. Determining the response of these structures when subjected to axisymmetric loadings (i.e., any combination of traction, torsion, and internal or external pressures) is an important task for the local structural analysis since it provides probable values for the loading distribution along the layers and, thus, allowing estimating the expected life of a riser using fatigue tools. Although finite element models have been increasingly used to accomplish this task in the last years, the simplicity and the reasonable accuracy provided by analytical models can be seen as reasons that justify their continued use, at least in the initial cycles of the design. However, any analytical model proposed for such a task must be checked with well-conducted experimental results in order to be considered as an acceptable analysis tool. The aims of this article are twofold: (i) to present the main results of experimental tests involving both internal pressure and traction loadings on a 63.5 mm (2.5 in.) flexible riser, carried out at the Institute for Technological Research of São Paulo (IPT), which can be used as a means of checking finite element or analytical models proposed by other researchers, and (ii) to compare some results obtained experimentally with those predicted by an analytical model which can also include any combination of axisymmetric loadings. Besides presenting full data concerning the internal structure of the riser, the experimental procedures used to perform the tests and the main results (e.g., Force × Displacement curves) are also presented. A brief discussion about the validity of some hypotheses that are usually assumed by analytical models found in the technical literature is made.

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