Effect of Changes in Tensile Properties Due to Cold Bending on Large Deformation Behavior of High-Grade Cold Bend Pipe

2002 ◽  
Author(s):  
Naoki Fukuda ◽  
Hiroshi Yatabe ◽  
Tomoki Masuda ◽  
Masao Toyoda
Keyword(s):  
Tensile Properties ◽  
Large Deformation ◽  
Deformation Behavior ◽  
High Grade ◽  
Bending Angle ◽  
Cold Bending ◽  
Bending Process ◽  
Opening Mode ◽  
Cold Bends ◽  
Good Agreement

The large deformation behavior of cold bend was experimentally and analytically investigated. Full-scale large deformation experiments were conducted on two API X80 grade cold bends with a bending angle of approximately 9 degrees for both closing and opening modes. Finite element (FE) analyses were also conducted to simulate the large deformation behavior by considering the distribution of tensile properties after the cold bending process. The results of the simulation were in good agreement with the large deformation experiments. The deformability of cold bend in the opening mode was greater than that in the closing mode. Changes in the tensile properties due to the cold bending process had a large influence on the deformability of cold bend. In particular, distribution of the part with work hardening after the cold bending process had large effect on the deformability in the closing mode.

Changes in Tensile Properties Due to Cold Bending of Line Pipes

2002 ◽  
Author(s):  
Naoki Fukuda ◽  
Hiroshi Yatabe ◽  
Tomoki Masuda ◽  
Masao Toyoda
Keyword(s):  
Tensile Properties ◽  
Analytical Model ◽  
Bauschinger Effect ◽  
Estimation Method ◽  
Tensile Tests ◽  
Full Scale ◽  
Small Scale ◽  
Cold Bending ◽  
Cold Bends ◽  
Good Agreement

The changes in the tensile properties of line pipes due to cold bending were experimentally and analytically investigated. Full-scale cold bending experiments were performed on API X60 and X80 grade line pipes. The reduction in the yield stress of the cold bends due to the Bauschinger effect was approximately 20% and 35% for X60 and X80, respectively. In order to evaluate the changes in the tensile properties of the pipes quantitatively, finite element (FE) analyses and small-scale experiments were conducted. The FE analytical model for simulating the strain distribution at various bending angles was verified with the results of the full-scale experiments. The tensile properties of the cold bends were in good agreement with those of the small-scale experiments using uni-axially prestrained specimens. Based on the present results, an estimation method was proposed for evaluating the distribution of the tensile properties after cold bending with the analytical model using the results of the tensile tests for prestrained specimens.

Tensile Properties of Cold Bends for Line Pipes

2007 ◽  
Vol 129 (3) ◽  
pp. 229-235 ◽  
Author(s):  
Naoki Fukuda ◽  
Hiroshi Yatabe ◽  
Tomoki Masuda ◽  
Masao Toyoda
Keyword(s):  
Tensile Properties ◽  
Tensile Tests ◽  
Full Scale ◽  
Small Scale ◽  
Fe Model ◽  
Cold Bending ◽  
Bending Process ◽  
Residual Strains ◽  
Cold Bends ◽  
The Relationship

To comprehensively investigate the tensile properties of cold bends, full-scale cold bending experiments, tensile tests using prestrained small-scale specimens, and finite element (FE) analyses of the cold bending processes were conducted on API 5L X60 and X80 grade line pipes. The tensile tests revealed that the tensile properties of the cold bends were comparable to the uniaxially prestrained specimens machined from the straight part of the pipes. A FE model simulating the cold bending process was verified with the full-scale experimental results in terms of the distributions of residual strains. These results supported a procedure for estimating the tensile properties of the cold bends with a combination of the FE model and the tensile tests using the prestrained specimens; the residual strains obtained from the FE model are transformed into the tensile properties based on the relationship between the residual strains and the tensile properties. This study clarified that the tensile properties come close to being uniformly distributed by reducing the distance between the bending locations; the distance between the bending locations has a significant influence on the overlap of adjacent deformed areas, which governs the distribution of the tensile properties of the cold bends.

Experimental and Analytical Study of Cold Bending Process for Pipelines

2003 ◽  
Vol 125 (2) ◽  
pp. 153-157 ◽  
Author(s):  
Naoki Fukuda ◽  
Hiroshi Yatabe ◽  
Shinobu Kawaguchi ◽  
Takahito Watanabe ◽  
Tomoki Masuda
Keyword(s):  
Analytical Study ◽  
Longitudinal Direction ◽  
Tensile Tests ◽  
Full Scale ◽  
Obvious Effect ◽  
Cold Bending ◽  
Bending Process ◽  
Strain Relationship ◽  
Cold Bends ◽  
Good Agreement

The behavior during the cold bending of pipelines was experimentally and analytically investigated. Full-scale cold bending experiments were performed on API X60 and X80 grade line pipes. Finite element (FE) analyses simulated the cold bending process by considering the contact interactions between a pipe and the components of the bending machine. The results of the simulation were in good agreement with the full-scale experiments. The stress-strain relationship and yield to tensile ratio (Y/T) had no obvious effect on the strain distribution after cold bending. The tensile tests quantitatively evaluated the decrease in the yield stress along the longitudinal direction on the cold bends due to the Bauschinger effect.

Numerical Simulation of Tube-Bending Process with Internal Pressure for Titanium Alloy Tube

2005 ◽  
Vol 475-479 ◽  
pp. 3279-3282
Author(s):  
Xia Huang ◽  
Yuan Song Zeng ◽  
Zhi Qiang Li ◽  
Xin Hua Zhang
Keyword(s):  
Titanium Alloy ◽  
Internal Pressure ◽  
Forming Process ◽  
Cold Bending ◽  
Bending Process ◽  
Thickness Prediction ◽  
Bending Radius ◽  
Experimental Values ◽  
Titanium Alloy Tube ◽  
Good Agreement

In this paper, a new cold bending process is presented to form the titanium alloy tubular part with small relative bend radius, that is, its centerline bending radius is less than 2 times the outside diameter of the tube. FEM is applied to simulate the forming process, and at the same time the results, such as the distribution of the stress and the wall thickness, prediction of defects area, the effects of the internal pressure and friction condition on the tube deformation, are also analyzed. Finally, experimental research was preformed. It is found that the numerical results are in good agreement with the experimental values.

Finite Element Analysis of Cold Bend Pipes Under Bending Loads

2010 ◽  
Author(s):  
Millan Sen ◽  
Roger Cheng
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Vertical Direction ◽  
Element Model ◽  
Element Analysis ◽  
Cold Bending ◽  
Bending Process ◽  
Cold Bends ◽  
Full Scale Tests ◽  
The Right

Cold bends are required in pipelines at locations of changes in horizontal or vertical direction in the right of way. Due to this change of direction, pipeline deformations caused by geotechnical or operational loading conditions tend to accumulate at the site of cold bends. These deformations may become sufficient to cause local buckling at the bend. For pipeline design, it is important to understand the level of deformation that a cold bend can accumulate prior to local buckling so that the strain capacity can be compared to the expected pipeline deformations. Evaluating the buckling strain of cold bends is extremely complex due to the residual stresses, ripples, and material transformations cause by the cold bending process. Accordingly a finite element model was developed herein. This model accounted for the cold bend geometry, initial imperfections, and the material transformations caused by the cold bending process. This model was validated against 7 full scale tests of cold bend pipes that were subjected to bend loading and internal pressure. The global and local behavior of this model exhibited reasonable correlation against the tests.

Analysis of the Contact Deformation of Tread Blocks

1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Behavior ◽  
Contact Deformation ◽  
The Finite Element Method ◽  
The Road ◽  
Loss Of Contact ◽  
Tread Rubber ◽  
Good Agreement ◽  
Rubber Block

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.

BELMALLOY

Alloy Digest ◽  
1954 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Shear Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
High Grade ◽  
Malleable Iron ◽  
Shock Resistance ◽  
High Torque

Abstract BELMALLOY is a high grade pearlitic malleable iron providing rigidity and shock resistance to high torque loads. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: CI-6. Producer or source: Belle City Malleable Iron Company.

NJZ ALLOY No. 1

Alloy Digest ◽  
1975 ◽  
Vol 24 (4) ◽  
Keyword(s):  
Corrosion Resistance ◽  
New Jersey ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Purity ◽  
Deep Drawing ◽  
Heat Treating ◽  
High Grade ◽  
High Ductility

Abstract NJZ ALLOY No. 1 is produced from high-grade, high-purity zinc with additions of lead, cadmium and iron. It gives excellent deep-drawing performance because of a combination of low hardness and strength, high ductility and very little tendency to work harden. It can be formed readily by conventional processes including spinning and its applications include such items as deep-drawn cans and jewelry. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep and fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, and machining. Filing Code: Zn-18. Producer or source: New Jersey Zinc Company.

scholarly journals Optimization of the flow conditions in the spawning ground of the Chinese sturgeon (Acipenser sinensis) through Gezhouba Dam generating units

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anyang Huang ◽  
Jinzhong Yao ◽  
Jiazhi Zhu ◽  
Xingchen Gao ◽  
Wei Jiang
Keyword(s):  
Spawning Ground ◽  
Chinese Sturgeon ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Acipenser Sinensis ◽  
Critically Endangered Species ◽  
Gezhouba Dam ◽  
Opening Mode ◽  
Suitable Area ◽  
Good Agreement

AbstractChinese sturgeon (Acipenser sinensis) is a critically endangered species, and waters downstream from Gezhouba Dam are the only known spawning ground. To optimize the velocity conditions in the spawning ground by controlling the opening mode of Gezhouba Dam generator units, a mathematical model of Chinese sturgeon spawning ground was established in FLOW-3D. The model was evaluated with velocity measurements, and the results were determined to be in good agreement. By inverting the 2016–2019 field monitoring results, the model shows that the preferred velocity range for Chinese sturgeon spawning is 0.6–1.5 m/s. Velocity fields of different opening modes of the generator units were simulated with identical discharge. The suitable-velocity area was maximal when all units of Dajiang Plant of Gezhouba Dam were open. For discharges below 12,000 m3/s, most of the area was suitable; for discharges above 12,000 m3/s, the suitable area rapidly decreased with increasing discharge. A comparison of suitable areas under high-flow showed that at discharges of 12,000–15,000 m3/s, opening 11–13 units on the left side was optimal. For discharges above 15,000 m3/s, all units should be open. We used these results to recommend a new operation scheme to support the conservation of Chinese sturgeon.

scholarly journals Optimal Design of the Shape of a Non-Ball Mandrel for Thin-Walled Tube Small Radius Cold Bending

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1221
Author(s):  
Lu Bai ◽  
Jun Liu ◽  
Ziang Wang ◽  
Shuanggui Zou
Keyword(s):  
Ideal Point ◽  
Small Radius ◽  
Grey Wolf Optimizer ◽  
Forming Quality ◽  
Hollow Section ◽  
Cold Bending ◽  
Bending Process ◽  
Before And After ◽  
Thin Walled Tube ◽  
Thin Walled

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.

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