Residual Stress Modeling of Induction-Bent Pipes

2012 ◽  
Author(s):  
Y. Ding ◽  
M. Yetisir ◽  
H. McDonald
Keyword(s):  
Residual Stress ◽  
Numerical Model ◽  
Induction Heating ◽  
Wall Thickness ◽  
Large Diameter ◽  
Measurement Data ◽  
Heating And Cooling ◽  
Bending Process ◽  
Before And After ◽  
Large Diameter Pipes

The induction bending process using local induction heating is widely used to produce large diameter pipes with relatively small bend radii at low tooling cost. This process was considered for the fabrication of stainless steel feeder pipes for CANDU® reactors instead of cold and warm bending processes. Wall thickness measurements were performed, before and after bending, using an ultrasonic testing method on a number of test bends fabricated with this induction bending process. Residual stress measurements have been performed on a test bend by X-ray diffraction. A numerical model has been developed using LS-DYNA® to predict the residual stress and the deformed shape of these bends. The numerical model has also been used to study the effect of some key input parameters, such as bending speed, bending temperature, process parameters of induction heating and cooling, and the yield strength of the feeder material. This information can be used to improve the bending process such that lower residual stress and more uniform wall thickness can be achieved. In this paper, the simulation work is summarized and the comparison between the simulation results and the measurement data are presented.

Effect of Edge Masking on Residual Stress of Hot-Rolled Strip on Run-Out Table

2015 ◽  
Vol 1095 ◽  
pp. 732-735
Author(s):  
Xiao Hua Liu ◽  
Feng Dong ◽  
Dong Cheng Wang
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Numerical Model ◽  
Rolled Strip ◽  
Hot Rolled Strip ◽  
Strip Flatness ◽  
Before And After ◽  
Microstructural Model ◽  
C Program ◽  
Hot Rolled

A numerical model including thermal and microstructural model is established for precisely prediction of residual stress of hot-rolled strip on run-out table. Temperature and phase transformation fraction are coupled and formulated for the calculation of thermal and transformation expansion that could induce internal stress. Residual stress for hot-rolled strip before and after coiling are calculated using C++ program. Influence of edge masking on residual stress is analyzed. It is concluded that edge masking makes the strip flatness better after coiling.

Continuing Structural Health Monitoring after Repair: Starting from Scratch?

2008 ◽  
Vol 56 ◽  
pp. 495-501
Author(s):  
Jyrki Kullaa
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Structural Health Monitoring ◽  
Finite Element Model ◽  
Health Monitoring ◽  
Measurement Data ◽  
Element Model ◽  
Structural Condition ◽  
Structural Health ◽  
Before And After

Aging structures need repairing if their lifetime is to be extended. If the structure has been monitored before and after repair, the information from both configurations can be utilized. The data before repair include the environmental or operational influences, whereas the data after repair represent the current structural condition. Also, if damage is proportional to the worked modifications, its extent can be assessed solely from the measurement data; no finite element model is needed. The proposed method is verified with a numerical model of a vehicle crane.

Residual Stresses Redistribution in Girth Weld Pipe After Reduction of the Wall Thickness

2017 ◽  
Author(s):  
Xavier Ficquet ◽  
Remi Romac ◽  
Karim Serasli ◽  
Ed J. Kingston
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Wall Thickness ◽  
Hole Drilling ◽  
Gas Oil ◽  
Internal Corrosion ◽  
The North ◽  
Before And After ◽  
The North Sea ◽  
Welded Pipe

Girth welded pipes, such as those located offshore on platforms in the North Sea, are subjected to highly corrosive environment. The need to consider welding residual stresses in the assessment of the fitness for service and damages to these pipes when investigating local corrosion damages across a welded region is therefore important for the operators of the platforms and the manufacturers of the pipes. This paper presents a review of work carried out to ascertain the welding residual stresses present within a thin-walled girth welded pipe mock-up made from steel API 5LX Grade 52 before and after reduction of the wall thickness. The mock-up was manufactured to replicate typical pipes used to convey gas, oil and water through the platforms. The mock-up was of diameter 30” and of thickness 19mm. The incremental deep hole drilling (iDHD), contour, hole drilling, XRD, and ultrasonic technique were applied to characterise the residual stresses in the weld and heat affected zone of the specimen. The residual stresses were then measured during the manufacture of a groove located on the weld at the ID and were compared to an FE prediction. Ultrasonic measurements were then carried out on the outer surface of the pipe and show a significant increase in the residual stress and could be used to monitor the changes in the residual stress caused by internal corrosion.

Optimization of Pipe Induction Bending Process Parameters

2017 ◽  
Author(s):  
T. S. Kathayat ◽  
Rajesh K. Goyal ◽  
Richard Hill ◽  
Tushal Kyada
Keyword(s):  
Induction Heating ◽  
Process Parameters ◽  
Water Pressure ◽  
Large Diameter ◽  
Water Flow Rate ◽  
Microstructural Analysis ◽  
Mechanical Tests ◽  
Complex Process ◽  
Bending Process ◽  
Bending Radius

Hot pushed induction heating is a bending process used to bend pipes having a small bending radius with a large diameter. This is a complex process since it involves mechanical process of bending and thermal process of localized induction heating. This paper deals with the optimization of induction bending process parameters such as bending speed, water flow rate, water pressure, air pressure and induction coil to water coil distance. Mother pipes of size 464 mm OD × 20.60 mm and grade API 5L X65MS/MO were used to make trial bends of 5D radius in 30° angle. Trial bends were subjected to mechanical tests and microstructural analysis to evaluate the effects of selected process parameters.

scholarly journals Modification of the optimization model for simulation of large-diameter pipes bending

2019 ◽  
Vol 254 ◽  
pp. 02024
Author(s):  
Marián Handrik ◽  
Filip Dorčiak ◽  
Milan Sága ◽  
Milan Vaško ◽  
Lenka Jakubovičová
Keyword(s):  
Optimization Model ◽  
Large Diameter ◽  
Fem Analysis ◽  
Bending Process ◽  
Large Diameter Pipes ◽  
Generate Model

This paper presents a modification of the existing optimalization model in order to increase the accuracy of the solution in the initial and the end part of the bend. Developed optimalization algorithms are implemented in the program MATLAB, and the simulation of the bending process is solved in the FEM program ADINA. Created optimisation program automatically generate model for FEM analysis and automaticaly analyses obtained results from FEM analysis.

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.

Estimation of Residual Stress in Spiral Welded Pipe: Regression and Numerical Model

2012 ◽  
Author(s):  
Abul Fazal M. Arif ◽  
Ahmad S. Al-Omari ◽  
Anwar K. Sheikh ◽  
Yagoub Al-Nassar ◽  
M. Anis
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Critical Role ◽  
Large Diameter ◽  
Element Model ◽  
Regression Equation ◽  
Field Analysis ◽  
Welding Parameters ◽  
Splitting Test ◽  
Welded Pipe

Double submerged spiral-welded pipe (SWP) is used extensively throughout the world for large-diameter pipelines. Fabrication-induced residual stresses in spiral welded pipe have received increasing attention in gas, oil and petrochemical industry. Several studies reported in the literature verify the critical role of residual stresses in the failure of these pipes. Therefore, it is important that such stresses are accounted for in safety assessment procedures such as the British R6 and BS7910. This can be done only when detailed information on the residual stress distribution in the component is known. In industry, residual stresses in spiral welded pipe are measured experimentally by means of destructive techniques known as Ring Splitting Test. In this study, statistical analysis and linear-regression modeling were used to study the effect of several structural, material and welding parameters on ring splitting test opening for spiral welded pipes. The experimental results were employed to develop an appropriate regression equation, and to predict the residual stress on the spiral welded pipes. It was found that the developed regression equation explains 36.48% of the variability in the ring opening. In the second part, a 3-D finite element model is presented to perform coupled-field analysis of the welding of spiral pipe. Using this model, temperature as well as stress fields in the region of the weld edges is predicted.

Validation of a numerical model used to predict phase distribution and residual stress in ferritic steel weldments

2014 ◽  
Vol 75 ◽  
pp. 1-19 ◽  
Author(s):  
Cory J. Hamelin ◽  
Ondrej Muránsky ◽  
Michael C. Smith ◽  
Thomas M. Holden ◽  
Vladimir Luzin ◽  
...  
Keyword(s):  
Residual Stress ◽  
Numerical Model ◽  
Ferritic Steel ◽  
Phase Distribution
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