scholarly journals Analysis of Residual Stress of Multi-pass Pipe Welding Considering 3 Dimensional Moving Heat Source Using Idealized Explicit FEM

2015 ◽  
Vol 33 (1) ◽  
pp. 69-81 ◽  
Author(s):  
Kazuki IKUSHIMA ◽  
Shinsuke ITOH ◽  
Satoru NISHIKAWA ◽  
Masakazu SHIBAHARA
Keyword(s):  
Residual Stress ◽  
Heat Source ◽  
Moving Heat Source ◽  
3 Dimensional ◽  
Pipe Welding

3-Dimensional Repair Weld Simulations: Bead Sequencing Studies

2004 ◽  
Author(s):  
C. D. Elcoate ◽  
R. J. Dennis ◽  
P. J. Bouchard ◽  
M. C. Smith
Keyword(s):  
Residual Stress ◽  
Heat Source ◽  
Flat Plate ◽  
Weld Bead ◽  
Moving Heat Source ◽  
End Effects ◽  
3 Dimensional ◽  
Sequencing Studies ◽  
Source Models ◽  
Modelling Assumptions

In current 3-dimensional multi-pass repair weld simulations each pass is generally modelled as a single continuous weld bead using either a simultaneous bead deposition or a progressive bead deposition moving heat source approach. In reality the length of typical manual metal arc (MMA) repair welds often necessitates the use of multiple weld beads for any individual pass. To investigate the modelling assumptions associated with this approximation a series of results are presented that simulate the deposition of a multi-bead, single MMA weld pass on a stainless steel flat plate. The simulations make use of a fabricated single bead weld test specimen to define the welding conditions. A number of different heat source models and bead sequencing scenarios have been investigated. These include moving heat source simulations, simultaneous bead laying methods (also called “block-dumped” methods) and combinations of the two. The work provides a useful insight into how certain modelling approximations affect weld residual stress distributions. It is concluded that moving heat source end effects are not sensitive to modelling assumptions made in weld beads remote from the stop end. However, residual stress predictions at the mid-length of a multi-bead weld pass on a flat plate are sensitive to the modelling assumptions. In particular, modelling each bead of a multi-bead weld pass can increase the stresses at mid-length relative to a simulation that deposits the whole pass in one go. One further observation made is that modelling the central bead of a multi-bead weld pass using a block-dumped technique (allowing a symmetry boundary condition to be used perpendicular to the weld bead) can result in inaccurate or misleading results.

SCC Test Verification of Effect of Moving Heat Source on FEM Evaluation for Weld Residual Stress of Butt-Weld Pipe

2009 ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Satoru Aoike ◽  
Yuka Fukuda ◽  
Osamu Saitou
Keyword(s):  
Residual Stress ◽  
Heat Source ◽  
Three Dimensional ◽  
Computation Time ◽  
Moving Heat Source ◽  
Low Carbon ◽  
Time Step ◽  
Butt Weld ◽  
Weld Residual Stress ◽  
Plastic Analysis

Weld residual stress of a small bore pipe was evaluated using three-dimensional thermal elasto-plastic analysis, which was based on the finite element method (FEM), taking into consideration the effect of a moving heat source during the butt-weld process. A moving heat source during the weld process complicates analysis process due to the necessity of considering the set welding conditions at each time step and this increases computation time. Therefore, there are remarkably few studies on the effect of a moving heat source during the weld process on the analytical results of weld residual stress for small bore pipes. We used this analysis to find the effect of the welding start/end on weld residual stress. Weld residual stress is not a circumferentially uniform state. Increased tensile and compressive residual stress occurred near the end position of the final welding pass. In addition, an accelerated stress corrosion cracking (SCC) test was carried out using a boiling 42% magnesium chloride (MgCl2) solution. In particular, butt-weld joints of low-carbon austenitic stainless steel (Type 316L) pipe, which is often used in boiling water reactors (BWRs), were examined. Comparison between three-dimensional thermal elasto-plastic analysis and accelerated SCC testing showed the tensile stress zone indicated by analysis agreed well with SCC occurrence indicated by examination.

Numerical Methods for Welding Simulation: The Next Technical Step

2008 ◽  
Author(s):  
N. A. Leggatt ◽  
R. J. Dennis ◽  
M. C. Smith ◽  
P. J. Bouchard
Keyword(s):  
Residual Stress ◽  
Numerical Methods ◽  
Heat Source ◽  
Measurement Techniques ◽  
Welding Process ◽  
Moving Heat Source ◽  
Computing Performance ◽  
Solution Accuracy ◽  
Welding Processes ◽  
Insight Into

Numerical methods have been established to simulate welding processes, often based around the use of methods which represent the welding process in a simplified manner. Simplified methods include simultaneous deposition of weld beads and bead lumping where stringers or individual weld beads are grouped together and deposited. These approaches are widely accepted, however the requirement for simplified methods often results in compromises to the solution accuracy usually driven by limitations in data and the capability of computing hardware. In many cases this compromise in accuracy is acceptable providing it is well understood, however there are frequently cases where such simplifications are unacceptable and improved representation of the welding process is required. In practice this generally implies the requirement for a full moving heat source simulation. The transition from simplified simulation methods to the next technical step, full moving heat source simulations, is now possible for a wide variety of scenarios as will be demonstrated in this paper. This paper presents two specific cases, a 3 pass slot weld and a multipass repair weld, where full moving heat source simulations have been considered necessary. For each of these cases the reasons why moving heat source methods are necessary and the benefits that this more demanding simulation technique offers are described. Furthermore the predicted residual stress results are compared with residual stress measurements using a variety of measurement techniques. The work provides an extremely useful insight into how moving heat source methods are now considered a practical analysis method for a wide variety of real world problems. Of further consideration is the fact that in the 2 years since the work reported in this paper was undertaken computing performance would have at least doubled.

scholarly journals Analysis of hyperbolic Pennes bioheat equation in perfused homogeneous biological tissue subject to the instantaneous moving heat source

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Ali Kabiri ◽  
Mohammad Reza Talaee
Keyword(s):  
Heat Source ◽  
Closed Form ◽  
Method Comparison ◽  
Closed Form Solution ◽  
Form Solution ◽  
Temperature Profiles ◽  
Moving Heat Source ◽  
Bioheat Equation ◽  
Perfusion Rate

AbstractThe one-dimensional hyperbolic Pennes bioheat equation under instantaneous moving heat source is solved analytically based on the Eigenvalue method. Comparison with results of in vivo experiments performed earlier by other authors shows the excellent prediction of the presented closed-form solution. We present three examples for calculating the Arrhenius equation to predict the tissue thermal damage analysis with our solution, i.e., characteristics of skin, liver, and kidney are modeled by using their thermophysical properties. Furthermore, the effects of moving velocity and perfusion rate on temperature profiles and thermal tissue damage are investigated. Results illustrate that the perfusion rate plays the cooling role in the heating source moving path. Also, increasing the moving velocity leads to a decrease in absorbed heat and temperature profiles. The closed-form analytical solution could be applied to verify the numerical heating model and optimize surgery planning parameters.

Temperature field in a hollow finite-length cylinder with an arbitrarily moving heat source

1972 ◽  
Vol 22 (3) ◽  
pp. 381-385 ◽  
Author(s):  
L. A. Brichkin ◽  
Yu. V. Darinskii ◽  
L. M. Pustyl'nikov
Keyword(s):  
Temperature Field ◽  
Heat Source ◽  
Finite Length ◽  
Moving Heat Source

Generalized Thermoelastic Responses of a Piezoelectric Rod Subjected to a Moving Heat Source

2007 ◽  
Vol 353-358 ◽  
pp. 1149-1152
Author(s):  
Tian Hu He ◽  
Li Cao
Keyword(s):  
Numerical Calculation ◽  
Heat Source ◽  
Laplace Transformation ◽  
Moving Heat Source ◽  
Governing Equations ◽  
Laplace Inversion ◽  
Thermally Induced ◽  
Numerical Laplace Inversion ◽  
Generalized Thermoelastic ◽  
Elastic Responses

Based on the Lord and Shulman generalized thermo-elastic theory, the dynamic thermal and elastic responses of a piezoelectric rod fixed at both ends and subjected to a moving heat source are investigated. The generalized piezoelectric-thermoelastic coupled governing equations are formulated. By means of Laplace transformation and numerical Laplace inversion the governing equations are solved. Numerical calculation for stress, displacement and temperature within the rod is carried out and displayed graphically. The effect of moving heat source speed on temperature, stress and temperature is studied. It is found from the distributions that the temperature, thermally induced displacement and stress of the rod are found to decrease at large source speed.

Sign in / Sign up

Export Citation Format

Share Document