scholarly journals Numerical Calculation of Stress Intensity Factors for Semi-Elliptical Surface Cracks in Buried-Arc Welded Thick Plates

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1809
Author(s):  
Krešimir Jukić ◽  
Mato Perić ◽  
Zdenko Tonković ◽  
Ivica Skozrit ◽  
Tomislav Jarak
Keyword(s):  
Stress Intensity ◽  
Arc Welding ◽  
Crack Opening ◽  
Weld Line ◽  
Welding Process ◽  
Surface Cracks ◽  
Mode Iii ◽  
Thick Plates ◽  
Crack Behavior ◽  
Good Agreement

The present study deals with the influence of residual stresses induced by the buried-arc welding on the crack behavior in two butt-welded 20 mm thick plates. The following steps were undertaken: the thermo-mechanical simulation of the welding process, the mapping of stress results from a finite element (FE) mesh used for the welding simulation to a new FE mesh with a crack, the stress balancing, and the stress intensity factor (SIF) calculation. The FE and weight function (WF) methods were used to investigate the SIFs at the deepest point of semi-elliptical surface cracks with different geometries, orientations, and positions in relation to the weld line. In the case of cracks perpendicular to the weld line, the FE and WF results showed a good agreement for smaller cracks, while deviation between the results increases with the size of the crack. Considering the SIF solutions for the cracks of arbitrary orientation, it was observed that for some cases, the SIF value for mode III of crack opening can be of significant influence.

Prediction of Temperature Distribution on Submerged Arc Welded Plates through Gaussian Heat Distribution Technique

2011 ◽  
Vol 284-286 ◽  
pp. 2477-2480 ◽  
Author(s):  
Aniruddha Ghosh ◽  
Somnath Chattopadhyaya
Keyword(s):  
Temperature Distribution ◽  
Arc Welding ◽  
Infinite Plate ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
High Deposition Rate ◽  
Microstructure Modeling ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Good Agreement

Submerged Arc Welding process (SAW) is a high quality, very high deposition rate welding process. It has lot of social and economical implecations.This paper makes an attempt to uncover an important area on studies of temperature distribution during submerged arc welding because this may pave the way for application of microstructure modeling, thermal stress analysis, residual stress/distribution and welding process simulation. Prediction of temperature variation of entire plates during welding through an analytical solution is derived from the transient multi dimensional heat conduction of semi infinite plate. The heat input that is applied on the plate is exactly same amount of heat lost for electric arc, which is assumed to be a moving double conical heat source with Gaussian distribution for Submerged Arc Welding process. Good agreement between predicted and experimental results has been achieved.

Mode III Stress Intensity Factors of Surface Crack in Round Bars

2011 ◽  
Vol 214 ◽  
pp. 192-196 ◽  
Author(s):  
Al Emran Ismail ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Mariyam Jameelah Ghazali ◽  
Ruslizam Daud
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Crack Depth ◽  
Crack Tip ◽  
Bending Moment ◽  
Surface Cracks ◽  
Intensity Factors ◽  
Mode Iii ◽  
Element Analysis ◽  
Proposed Model

This study presents a numerical investigation on the stress intensity factors (SIF), K of surface cracks in round bars that were obtained under pure torsion loadings or mode III. ANSYS finite element analysis (FEA) was used to determine the SIFs along the crack front of surface cracks embedded in the solid circular bars. 20-node isoparametric singular elements were used around the crack tip by shifting the mid-side node ¼-position close to a crack tip. Different crack aspect ratio, a/b were used ranging between 0.0 to 1.2 and relative crack depth, a/D were ranged between 0.1 to 0.6. Mode I SIF, KI obtained under bending moment was used to validate the proposed model and it was assumed this proposed model validated for analyzing mode III problems. It was found that, the mode II SIF, FII and mode III SIF, FIII were dependent on the crack geometries and the sites of crack growth were also dependent on a/b and a/D.

A Model for Determining Crack Opening Stress Intensity Factor Ratio under Tri-Axial Stress State

2005 ◽  
Vol 297-300 ◽  
pp. 1572-1578
Author(s):  
Yu Ting He ◽  
Feng Li ◽  
Rong Shi ◽  
G.Q. Zhang ◽  
L.J. Ernst ◽  
...  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Stress State ◽  
Intensity Factor ◽  
Present Model ◽  
Axial Stress ◽  
Crack Opening ◽  
Factor Ratio ◽  
Crack Opening Stress ◽  
Good Agreement

When studying 3D fatigue crack growth behaviors of materials, to determine the crack opening stress intensity factor ratio is the key issue. Elastic-plastic Fracture Mechanics theory and physical mechanism of cracks’ closure phenomena caused by plastic deformation are employed here. A model for determining the crack opening stress intensity factor ratio under tri-axial stress state is presented. The comparison of the present model with available data and models shows quite good agreement.

scholarly journals Comparison of BS 7910 and API 579-1/ASME FFS-1 Solutions With Regards to Leak-Before-Break

2016 ◽  
Author(s):  
Renaud Bourga ◽  
Bin Wang ◽  
Philippa Moore ◽  
Yin Jin Janin
Keyword(s):  
Experimental Data ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Material Properties ◽  
Crack Opening ◽  
Surface Cracks ◽  
Not Given ◽  
Reference Stress ◽  
The Common ◽  
Leak Before Break

One of the ways to aid the decision whether or not to live with defects in pressurised components is through the demonstration of Leak-Before-Break (LBB). In this paper, three of the main solutions to carry out the LBB assessment, namely Stress Intensity Factor (SIF), Reference Stress (RS) and Crack Opening Area (COA) have been evaluated and compared for both BS 7910 and API 579/ASME FFS-1 standards. Differences with respect to the choice of solutions and boundary conditions are illustrated and discussed. The same applied loads and material properties have been used when applying each procedure. Different geometries for potential pressurised components which are of interest with regards to LBB have been considered for each solution. Focus is made on cylinders where axially and circumferentially oriented through-wall and surface cracks were analysed. While SIF solutions produce similar results for both standards, reference stress solutions show greater differences in the results. However, in LBB assessments it is the reference stress solution which is more relevant, since most LBB assessments pre-suppose the material to be ductile. In terms of COA, solutions are not given exactly equivalent, however they seem to agree well within the common range of applicability. Differences in the assessment route between the standards is also discussed. Experimental data from literature has also been compared to the different standard predictions, to illustrate the accuracy of the solutions for axially oriented surface cracks. The ability of solutions to predict the boundary between leak and break is discussed, in relation to how this shows the level of conservatism.

A study on an automatic seam tracking system by using an electromagnetic sensor for sheet metal arc welding of butt joints

2002 ◽  
Vol 216 (6) ◽  
pp. 911-920 ◽  
Author(s):  
B-H You ◽  
J-W Kim
Keyword(s):  
Sheet Metal ◽  
Arc Welding ◽  
Tracking System ◽  
Weld Line ◽  
Welding Process ◽  
Seam Tracking ◽  
Displacement Sensor ◽  
Tracking Accuracy ◽  
Metal Arc Welding ◽  
Electromagnetic Sensor

Many sensors, such as the vision sensor and the laser displacement sensor, have been developed to automate the arc welding process. However, these sensors have some problems due to the effects of arc light, fumes and spatter. An electromagnetic sensor, which utilizes the generation of an eddy current, was developed for detecting the weld line of a butt joint in which the root gap size was zero. An automatic seam tracking system designed for sheet metal arc welding was constructed with a sensor. Through experiments, it was revealed that the system had an excellent seam tracking accuracy of the order of ±0.2mm.

scholarly journals Stress Analysis and Stress-Intensity Factors for Finite Geometry Solids Containing Rectangular Surface Cracks

1977 ◽  
Vol 44 (3) ◽  
pp. 442-448 ◽  
Author(s):  
J. P. Gyekenyesi ◽  
A. Mendelson
Keyword(s):  
Stress Intensity ◽  
Displacement Field ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Crack Opening ◽  
Crack Depth ◽  
Elastic Equilibrium ◽  
Finite Geometry ◽  
Surface Cracks ◽  
Intensity Factors

The line method of analysis is applied to the Navier-Cauchy equations of elastic equilibrium to calculate the displacement field in a finite geometry bar containing a variable depth rectangular surface crack under extensionally applied uniform loading. The application of this method to these equations leads to coupled sets of simultaneous ordinary differential equations whose solutions are obtained along sets of lines in a discretized region. Using the obtained displacement field, normal stresses, and the stress-intensity factor variation along the crack periphery are calculated for different crack depth to bar thickness ratios. Crack opening displacements and stress-intensity factors are also obtained for a through-thickness, center-cracked bar with variable thickness. The reported results show a considerable potential for using this method in calculating stress-intensity factors for commonly encountered surface crack geometries in finite solids.

Evaluation of High Penetration Hybrid Laser-GMAW Welding Process Productivity Applied in the Joining of Thick Plates and Pipelines

2022 ◽  
Author(s):  
Rafael Gomes Nunes Silva ◽  
Max Baranenko Rodrigues ◽  
Milton Pereira ◽  
Koen Faes
Keyword(s):  
Laser Beam ◽  
Arc Welding ◽  
Manufacturing Industry ◽  
Operating Time ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Major Influence ◽  
Thick Plates ◽  
High Penetration ◽  
Welding Processes

Abstract Welding processes are present in all sectors of the industry, highlighting the manufacturing industry of thick plates and pipelines. In these applications, welding processes have a major influence on costs, schedules, risk analysis and project feasibility. Conventional arc welding processes, such as the gas metal arc welding (GMAW) process, have limitations when applied to high thickness joints due to their maximum achievable penetration depth. On the other hand, the laser beam welding (LBW) welding process, despite reaching high penetration depths, has several limitations mainly regarding the geometric tolerance of the joint. In this regard, the hybrid laser-arc welding (HLAW) process emerges as a promising bonding process, combining the advantages of the GMAW and LBW processes into a single melting pool. Despite the many operational and metallurgical advantages, the HLAW process presents a high complexity due to the high number of parameters involved and the interaction between the laser beam and the electric arc. The present work discusses the challenges involved in the parametrization of the HLAW process applied to the joining of thick plates and pipes, and empirically evaluated a comparison between the HLAW and GMAW processes, showing a reduction of operating time of approximately 40 times, and a reduction of consumption of shielding gas and filler material of approximately 20 times, evidencing the technical and financial contribution of the hybrid process.

Evaluation of the sound signal based on the welding current in the gas—metal arc welding process

2003 ◽  
Vol 217 (5) ◽  
pp. 483-494 ◽  
Author(s):  
M Čudina ◽  
J Prezelj
Keyword(s):  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Welding Current ◽  
Sound Signal ◽  
Frequency Noise ◽  
Metal Arc Welding ◽  
Arc Welding Process ◽  
Good Agreement

In this paper sound generated during the gas-metal arc welding process in the short-circuit mode was studied. Theoretical and experimental analyses of the acoustic signals have shown that there are two main noise-generating mechanisms. The first mechanism generating characteristic sound impulses is arc extinction and arc ignition; the second noise-generating mechanism is the arc itself, which acts as an ionization sound source and produces mainly high-frequency noise of a low level. The sound signal is used for assessing and monitoring the welding process and for prediction of welding process stability and quality. A new algorithm based on the measured welding current was established for the calculation of emitted sound during the welding process. The algorithm was verified for different supply voltages and for different welding materials. The comparisons have shown that the calculated values are in good agreement with measured values of the sound signal.

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