scholarly journals Influencing Variables of Drawing Process using Magnesium Tubes

2019 ◽  
Vol 9 (2) ◽  
pp. 598-601
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Tube Wall ◽  
Drawing Process ◽  
Spring Back ◽  
Bending Angle ◽  
Tube Wall Thickness ◽  
The Cross ◽  
Back Angle ◽  
Thinning Rate

The present work examines the deformation of magnesium tubes using drawing process. During examination, absence of wrinkling and cracking is witnessed at 303k. The effect of mandrel on the cross section of the extruded tubes, wall thickness and spring-back of the bent tube are vividly discussed. Results show that presence of mandrel decreases the cross section of distortion and the spring back angle. Further, the present investigation clarifies the thinning rate of tube wall thickness. It is found that at the bending angle of 90° largest distortion is witnessed.

Structural Integrity Assessment of Steam Generator Tubes Using a New EPRI Statistical Approach

2002 ◽  
Author(s):  
Carlos Alexandre de Jesus Miranda ◽  
Miguel Mattar Neto
Keyword(s):  
Steam Generator ◽  
Wall Thickness ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Tube Wall ◽  
New Approach ◽  
Inconel 600 ◽  
Integrity Assessment ◽  
Tube Wall Thickness ◽  
Uniform Tube

A fundamental step in tube plugging management of a Steam Generator (SG), in a Nuclear Power Plant (NPP), is the tube structural integrity evaluation. The degradation of SG tubes may be considered one of the most serious problems found in PWRs operation, mainly when the tube material is the Inconel 600. The first repair criterion was based on the degradation mode where a uniform tube wall thickness corrosion thinning occurred. Thus, a requirement of a maximum depth of 40% of the tube wall thickness was imposed for any type of tube damage. A new approach considers different defects arising from different degradation modes, which comes from the in-service inspections (NDE) and how to consider the involved uncertainties. It is based on experimental results, using statistics to consider the involved uncertainties, to assess structural limits of PWR SG tubes. In any case, the obtained results, critical defect dimensions, are within the regulatory limits. In this paper this new approach will be discussed and it will be applied to two cases (two defects) using typical data of SG tubes of one Westinghouse NPP. The obtained results are compared with ‘historical’ approaches and some comments are addressed from the results and their comparison.

The Formation of Tracheae and Tracheoles in Rhodnius prolixus

1958 ◽  
Vol s3-99 (45) ◽  
pp. 29-46
Author(s):  
M. LOCKE
Keyword(s):  
Axial Compression ◽  
Wall Thickness ◽  
Tube Wall ◽  
Rhodnius Prolixus ◽  
Axial Orientation ◽  
Tube Wall Thickness ◽  
Walled Cylinder ◽  
Tangential Orientation

The formation of tracheae in Rhodnius is described by the hypothesis of expansion and buckling. The cuticulin lining is at first a smooth-walled cylinder. Later it expands equally in each direction, increasing in diameter but buckling in the axis. An engineering expression describing symmetrical buckling in a cylinder under uniform axial compression has been applied to this process. Agreement was obtained between the expected and observed values for buckling frequency and tube-wall thickness. The taenidia are formed within the buckles, their amplitude being proportional to the increase in diameter. The axial orientation of the chitin micelles in the lining membrane and the tangential orientation in the taenidia are consistent with their being oriented by the stresses expected during expansion and buckling. The formation of tracheoles may also be described by the expansion and buckling hypothesis.

Experimental and Numerical Studies on Flexural Behavior of Casing Joint of Square Steel Tube

2010 ◽  
Vol 163-167 ◽  
pp. 417-420
Author(s):  
Min Ding ◽  
Zhen Hua Hou ◽  
Xiu Gen Jiang ◽  
Yu Zhi He ◽  
Guang Kui Zhang ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Failure Modes ◽  
Shear Failure ◽  
Tube Wall ◽  
Edge Length ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Tube Wall Thickness ◽  
Square Steel Tube

The tests on thirteen specimens of casing joints of square steel tube were conducted to investigate the flexural behavior of the joints. And numerical simulation studies on that were carried out by ANSYS/LS-DYNA. On this basis, effects of tube wall thickness, tube edge length, and inserting depth on failure mode, ultimate flexural capacity and deformation of the joints were discussed. The results show that there are two types of failure modes, i.e., inside tube yield failure and outside tube shear failure. Ultimate flexural capacity and rigidity of the joints increased with the inserting depth increasing. The ultimate flexural capacity is proportional to tube shear strength, tube wall thickness, inserting depth, and tube edge length.

Study of NC Cold Tube Bending Spring-Back Characteristics

2010 ◽  
Vol 154-155 ◽  
pp. 202-208 ◽  
Author(s):  
Yi Nan Lai ◽  
Sheng Le Ren ◽  
Zeng Lou Li ◽  
Jun Tao Gu ◽  
Guang Fei Wu
Keyword(s):  
High Reliability ◽  
Prediction Equation ◽  
Strong Nonlinearity ◽  
Spring Back ◽  
Tube Bending ◽  
Bending Angle ◽  
Bending Process ◽  
Elasto Plasticity ◽  
Bending Radius ◽  
Back Angle

The unloading spring-back of tubes during its manufacturing process shows a strong nonlinearity, which greatly influences the precision of parts. In this paper, the strain distribution of bending tubes was analyzed based on the elasto-plasticity theory, and the theoretical equation for spring-back of tubes was derived. The numerical simulation model for cold tube-bending process was developed with prediction error of 9% compared with experimental results, indicating high reliability of the model. The 12Cr1MoV and 20G tubes were used to analyze the effects of bending angle, bending radius and bending speed on the spring-back of tubes. The prediction equation of spring-back was built, which shows that the spring-back tendency was in accordance with theoretical analysis results. The simulated results show that the spring-back angle is linearly proportional to the bending angle within a certain range. In addition, it is proportional to the relative bending radius and the bending speed.

Joining by Forming of Tubes to Sheets with Counterbored Holes

2018 ◽  
Vol 767 ◽  
pp. 421-428 ◽  
Author(s):  
Luis M. Alves ◽  
Rafael M. Afonso ◽  
Carlos M.A. Silva ◽  
Paulo A.F. Martins
Keyword(s):  
Analytical Model ◽  
Cross Section ◽  
Room Temperature ◽  
Tube Wall ◽  
Rectangular Cross Section ◽  
Dissimilar Materials ◽  
Forming Process ◽  
Element Analysis ◽  
Joining By Forming ◽  
Tube Wall Thickness

This paper presents a new joining by forming process for connecting tubes to sheets. The process consists of forming an annular flange with rectangular cross section by partial sheet-bulk of the tube wall thickness and performing the mechanical interlock by upsetting the free tube end against a flat-bottomed (counterbored) sheet hole. The presentation identifies the variables and the workability limits of the process and includes an analytical model to assist readers in the design of the new joints. The new proposed joining by forming process and the corresponding analytical model are validated by experimentation and numerical simulation using finite element analysis. The process allows connecting tubes to sheets made from dissimilar materials at room temperature, avoids the utilization of addition materials or adhesives and produces joints that are easy to disassembly at the end of live, allowing recyclability of the tubes and sheets.

Numerical Simulation Studies on Tension Behavior of Casing and Dowel Joint of Square Steel Tube

2010 ◽  
Vol 156-157 ◽  
pp. 1555-1558
Author(s):  
Min Ding ◽  
Zhen Hua Hou ◽  
Xiu Gen Jiang ◽  
Zi Chen Lin ◽  
Guang Kui Zhang ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Failure Modes ◽  
Tube Wall ◽  
Tensile Load ◽  
Steel Tube ◽  
Element Analysis ◽  
Tube Wall Thickness ◽  
Dowel Joint ◽  
Square Steel Tube ◽  
Tube Failure

The study on tension behavior of casing and dowel joint of square steel tube was carried out by using finite element analysis software ANSYS/LS-DYNA with consideration of geometric nonlinearity, material nonlinearity and contact nonlinearity. On this basis, the effects of inside tube wall thickness, main tube wall thickness, and inserting depth on failure mode, ultimate tensile load and deformation of casing and dowel joint of square steel tube was discussed. The results show that there are three types of failure modes, i.e., bolt failure, inside tube failure and main tube failure, when the joints are subjected to axial tension force. Compare to the joint with the same wall thickness of inside tube and main tube, the reduction of wall thickness of inside tube or main tube will weaken greatly the ultimate tensile load of the joint. The ultimate tensile load of casing and dowel joints is proportional to bolt shear strength, tube wall thickness, inserting depth, and tube edge length. The fruits are useful to the design and application of casing and dowel joints of square steel tube.

scholarly journals ASSESSMENT OF THE PROXIMITY OF DESIGN TO MINIMUM MATERIAL CAPACITY SOLUTION OF PROBLEM OF OPTIMIZATION OF THE FLANGE WIDTH OF I-SHAPED CROSS-SECTION RODS WITH ALLOWANCE FOR STABILITY CONSTRAINTS OR CONSTRAINTS FOR THE VALUE OF THE FIRST NATIONAL FREQUE

2020 ◽  
Vol 16 (2) ◽  
pp. 71-82 ◽  
Author(s):  
Leonid Lyakhovich ◽  
Pavel Akimov ◽  
Boris Tukhfatullin
Keyword(s):  
Objective Function ◽  
Natural Frequency ◽  
Cross Section ◽  
Wall Thickness ◽  
Optimal Solution ◽  
Computational Process ◽  
Flange Thickness ◽  
The Cross ◽  
Special Approach ◽  
Shaped Cross Section

There are known methods for optimizing the flange width of I-shaped cross-section rods with stability constraints or the constraints for the value of the first natural frequency. Corresponding objective function has the form of the volume of the flange material for the case when only the flange width varies and the cross-section height, wall thickness and flange thickness are specified. Special criterion for assessment of proximity of corresponding an optimal solution to the design of minimal material capacity was formulated for the considering problem. In this case, the resulting solution may not meet some other unaccounted constraints, for example, strength requirements. Modification of solution in order to meet previously unaccounted constraints does not allow researcher to consider such design as optimal. In the distinctive paper allowance for strength requirements, stability constraints or constraints for the value of the first natural frequency are proposed within considering problem of optimization. Special approach is formulated, which proposes to assess proximity to the design of minimum of material capacity obtained as a result of optimization. Increment of the objective function and criteria corresponding to constrains and restrictions are under consideration within computational process.

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