scholarly journals Study the Effect of Forming Media on the Hydroforming Process for Copper Tube

2018 ◽  
Vol 14 (1) ◽  
pp. 52-66
Author(s):  
Rusul AbdulKareem Salman ◽  
Hani Aziz Ameen ◽  
Kadhim Mijbel Mashloosh
Keyword(s):  
Natural Rubber ◽  
Internal Pressure ◽  
Thickness Distribution ◽  
Equivalent Stress ◽  
Hydraulic Pressure ◽  
Hydroforming Process ◽  
The Media ◽  
Industrial Rubber ◽  
Better Than ◽  
Tube Metal

To observe the effect of media of the internal pressure on the equivalent stress distribution in the tube, an experimental study is done by constructing a testing rig to apply the hydraulic pressure and three dies are manufactured with different bulging configurations (square, cosine, and conical). In the other part, ANSYS APDL is generated to analyze the bulging process with hydraulic and rubber (natural and industrial) media. It was found that when the media is a rubber, the stress is decreased about 9.068% in case of cosine die and 5.4439% in case of conical die and 2.8544% in case of square die. So, it can be concluded that the internal pressure in the rubber media is much better than in hydraulic media. Also, the force needed for forming the shape using rubber is higher than that of hydraulic and the force needed to form using industrial rubber is higher than of natural rubber. The thickness distribution in the tube wall in case of rubber media is better than that for hydraulic media and for the industrial rubber is better than that for natural rubber for the same dies. In case of hydraulic, the lower forming pressure is needed to bulging process compared with the rubber media since height stress in the tube metal is existed, which causes the failure.   For the case of rubber, the forming pressure that was needed to bulge process is higher when compared with the hydraulic media but with less stress in tube metal and the failure in the wall is not existed with rubber media for the same pressure of hydraulic.

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 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.

Process Parameter Optimization for Better Hydro-Forming Performance of a Trailing Arm Tube

2013 ◽  
Vol 465-466 ◽  
pp. 704-708
Author(s):  
Shen Yung Lin ◽  
Hong Yi Liao
Keyword(s):  
Process Parameters ◽  
Wall Thickness ◽  
Tube Wall ◽  
Thickness Distribution ◽  
Equivalent Stress ◽  
Process Parameter ◽  
Hydraulic Pressure ◽  
Forming Process ◽  
Tube Wall Thickness ◽  
Forming Characteristics

This work presents the tube forming characteristics of a trailing arm which the whole forming processes are arranged through pre-bending twice and hydro-forming once. This work utilizes the finite element method to simulate the hydro-forming process of the trailing arm by changing the process parameters, such as velocity of left and right punches and internal hydraulic pressure, etc. The effects of process parameters on the distribution states of the tube wall-thickness, distribution of equivalent stresses and strains, and formability of the forming arm are thus investigated. Taguchi method, orthogonal array and factor response are then applied together to determine the optimal process parameter combinations corresponding to two single-quality objects, minimum tube wall-thickness and maximum equivalent stress, with nominal-the-best and smaller-the-better, respectively. It shows that the velocity of the right punch for the billet material axial feeding supplement should be larger than that of the left punch preventing the uneven bursting of the tube-wall on right-end. The analysis of variance also shows that left punch velocity is a major contribution parameter for tube wall-thickness while that primarily affects the equivalent stress is the internal pressure.

Study of Bulging-Pressing Compound-Deforming Automobile Axle Housing with a Common Press

2012 ◽  
Vol 217-219 ◽  
pp. 1972-1977
Author(s):  
Lian Dong Wang ◽  
Ya Ping Cui ◽  
Dong Feng Yang
Keyword(s):  
Internal Pressure ◽  
Cross Sections ◽  
Hydraulic Pressure ◽  
Variable Diameter ◽  
Forming Technology ◽  
Filling Ability ◽  
Hydroforming Process ◽  
Housing Needs ◽  
Corner Filling

The conventional hydroforming process for automobile axle housing needs a large-tonnage press and has the drawback of the dome part being apt to burst due to the large thinning. A new forming technology, bulging-pressing compound-deforming for automobile axle housing, is proposed, which is suitable for the large variable-diameter tube parts with special-shaped cross-sections. The initial tube is made into the axisymmetric peforming tube after the ends necked and the middle hydroformed, and which then is pressed into the axle housing sample by the dies. For a small automobile axle housing, the process tryout and the pressing dies were designed, and the axle housing samples were successfully produced with a common press. Compare with the conventional hydroforming process, the forming corner radiuses of present samples are smaller and the internal pressure decreased 60%. The results show that the process has the advantages of good corner-filling ability and low internal hydraulic pressure.

PENGEMBANGAN MEDIA BIG BOOK UNTUK MENINGKATKAN HASIL BELAJAR PECAHAN SENILAI SISWA SD

2018 ◽  
Vol 16 (1) ◽  
pp. 67-76
Author(s):  
Disyacitta Neolia Firdana ◽  
Trimurtini Trimurtini
Keyword(s):  
Learning Outcomes ◽  
Large Scale ◽  
Fourth Grade ◽  
Learning Activities ◽  
Equivalent Fractions ◽  
Fourth Grade Students ◽  
Teacher Needs ◽  
The Media ◽  
Test Result ◽  
Better Than

This research aimed to determine the properness and effectiveness of the big book media on learning equivalent fractions of fourth grade students. The method of research is Research and Development  (R&D). This study was conducted in fourth grade of SDN Karanganyar 02 Kota Semarang. Data sources from media validation, material validation, learning outcomes, and teacher and students responses on developed media. Pre-experimental research design with one group pretest-posttest design. Big book developed consist of equivalent fractions material, students learning activities sheets with rectangle and circle shape pictures, and questions about equivalent fractions. Big book was developed based on students and teacher needs. This big book fulfill the media validity of 3,75 with very good criteria and scored 3 by material experts with good criteria. In large-scale trial, the result of students posttest have learning outcomes completness 82,14%. The result of N-gain calculation with result 0,55 indicates the criterion “medium”. The t-test result 9,6320 > 2,0484 which means the average of posttest outcomes is better than the average of pretest outcomes. Based on that data, this study has produced big book media which proper and effective as a media of learning equivalent fractions of fourth grade elementary school.

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.

3-D Finite Element Simulation of Pulsating T-Shape Hydroforming of Tubes

2007 ◽  
Vol 340-341 ◽  
pp. 353-358 ◽  
Author(s):  
M. Loh-Mousavi ◽  
Kenichiro Mori ◽  
K. Hayashi ◽  
Seijiro Maki ◽  
M. Bakhshi
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Finite Element Simulation ◽  
Wall Thickness ◽  
Filling Ratio ◽  
Shape Accuracy ◽  
Element Simulation ◽  
Hydroforming Process ◽  
Good Agreement

The effect of oscillation of internal pressure on the formability and shape accuracy of the products in a pulsating hydroforming process of T-shaped parts was examined by finite element simulation. The local thinning was prevented by oscillating the internal pressure. The filling ratio of the die cavity and the symmetrical degree of the filling was increased by the oscillation of pressure. The calculated deforming shape and the wall thickness are in good agreement with the experimental ones. It was found that pulsating hydroforming is useful in improving the formability and shape accuracy in the T-shape hydroforming operation.

Study on Dehydration Process of Wet Natural Rubber by Single Screw Dehydrator and Properties of Dry Natural Rubber

2011 ◽  
Vol 418-420 ◽  
pp. 544-547
Author(s):  
Mei Chen ◽  
Fu Quan Zhang ◽  
Yong Zhou Wang ◽  
Mao Fang Huang ◽  
Wei Yong Deng
Keyword(s):  
Natural Rubber ◽  
Thermal Oxidation ◽  
Hammer Mill ◽  
Dehydration Process ◽  
Hot Air Drying ◽  
Single Screw ◽  
Hot Air ◽  
Unit Value ◽  
Better Than ◽  
Dehydration Effect

In this work, one self-invented closed single screw dehydrator was used to dehydrate wet natural rubber, instead of current three opened crepers and one hammer mill at home and abroad. The dehydration technology and the properties of the obtained dry natural rubber were studied. The results show that single screw dehydrator can simplify dehydration process. The water consumption of single screw dehydrator is 20% of current productive technology, meaning a lower wastewater discharge and treatment cost of wastewater. The moisture content of dehydrated natural rubber is lower than 20%, a good dehydration effect. The dry natural rubber dehydrated with single screw dehydrator has an improved thermal-oxidation ageing resistance whether dried by hot-air or microwave. The thermal-oxidation ageing resistance of natural rubber dried by microwave is better than that of hot-air drying, the value of initial plasticity (P0) and plasticity retention index (PRI) are 29.3 unit value and 19.26 unit value greater than that of SCR5 in GB/T 8081, respectively.

Nouvelles (vraies et fausses) de conversions (vraies et fausses) de monarques étrangers, imprimées en France aux XVIe-XVIIe siècles

2021 ◽  
pp. 15-43
Author(s):  
Vincent Masse
Keyword(s):  
17Th Century ◽  
News Report ◽  
News Reporting ◽  
News Reports ◽  
Current Information ◽  
The Media ◽  
False News ◽  
High Level ◽  
Better Than

Printed news reports circulated, in the 16th and 17th century, which revealed the sudden conversion to Christianity – some were real, but several were invented – of powerful monarchs from abroad. How were such announcements written or invented? Different scenarios existed. There was genuine news, to which were added cosmetic and false details, or sometimes overly enthusiastic interpretations. There was false news, although invented, arguably, to simplify the reporting of real upheavals on the scene of world affairs – such as the entrance on the historical stage of the Safavid dynasty, fantasized in the media as the conversion of Ismail I (in 1508) or Abbas I (in 1606). The strange case of La conversion de trois grands rois [The Conversion of Three Great Kings] helps in distinguishing two falsification mechanisms, or in this case two steps: in 1571, it was the fraudulent mixing of excerpts from genuine Jesuit letters; in 1588, 1608 and 1609, the same news report circulated anew, with all of its dates replaced by current ones. Truth and fiction thus intertwined better than they clashed, and paradoxically at the very time when genuine and current information about Persia, India and Indonesia was starting to circulate in Europe. The existence of such chimerical news also indicates that, as the industry of news reporting was developing, the particular desirability of reports on high-level conversions helped them prevail over other news more genuine, yet less appealing.

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