The effect of weld geometry and residual stresses on the fatigue of welded joints under combined loading

1998 ◽  
Vol 77 (1-3) ◽  
pp. 201-208 ◽  
Author(s):  
T.Ninh Nguyen ◽  
M.A. Wahab
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Combined Loading ◽  
Weld Geometry

State-of-the-Art: Fatigue Life Extension of Offshore Installations

2012 ◽  
Author(s):  
Luis Lopez Martinez ◽  
Zuheir Barsoum ◽  
Anna Paradowska
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Test ◽  
Welded Joints ◽  
Life Extension ◽  
Stress Concentrations ◽  
Weld Geometry ◽  
Compressive Stresses ◽  
Ultrasonic Peening

The use of fatigue life improvement techniques and specifically ultrasonic peening treatment to extend the service life of offshore structures has become an accepted practice during the last five years. The understanding of the process as well as equipment’s upgrading for treatment in-situ including quality control and assurance have been developed up to a level that it has become a current practice in many parts of the world. However, the efficiency of the ultrasonic peening is strictly dependent on the deep understanding of significant fatigue parameters as weld defects, stress concentrations and residual stresses and their interaction. In this paper we attempt to present the current knowledge and the physical reasons why the ultrasonic peening treatment is able to improve the fatigue life of welded joints. The local weld geometry or stress concentration, weld imperfections as well as welding residual stresses are all modified and improved by the application of ultrasonic peening. Local weld geometry and weld process inherent weld imperfections are the factors primarily influencing the fatigue strength in welded joints. Comprehensive studies have been carried out during the last 20 years in order to detect and document the weld defects as well as to understand their origin and effect on the fatigue strength of welds. Analogous efforts have been dedicated to understand and document the influence of local weld geometries on the stress concentrations and its influence on endurance and structural integrity. Similarly, efforts have been done to understand the influence of the relaxation by external loads of the by the ultrasonic peening treatment induced compressive stresses. Fatigue test results of ultrasonic peening treated relevant weld details have been used to assess the potential life extension. The results showed four to six times fatigue life extension. The spectrum fatigue test was designed to confirm that relaxation by service loads of the induced compressive stresses during ultrasonic peening treatment would not diminish the benefit.

Effect of weld geometry and residual stresses on fatigue in butt-welded joints

2002 ◽  
Vol 79 (7) ◽  
pp. 467-482 ◽  
Author(s):  
Tso-Liang Teng ◽  
Chin-Ping Fung ◽  
Peng-Hsiang Chang
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Weld Geometry

The Influence of Loads Superposition, Deterioration Due to Cracks and Residual Stresses on the Strength of Tubular Junction

2017 ◽  
Vol 68 (6) ◽  
pp. 1267-1273
Author(s):  
Valeriu V. Jinescu ◽  
Angela Chelu ◽  
Gheorghe Zecheru ◽  
Alexandru Pupazescu ◽  
Teodor Sima ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Residual Stresses ◽  
Bending Moment ◽  
Combined Loading ◽  
Torsional Moment ◽  
Calculation Methods ◽  
State Of Stress ◽  
Cracked Structures ◽  
Total Participation ◽  
Theoretical Results

In the paper the interaction of several loads like pressure, axial force, bending moment and torsional moment are analyzed, taking into account the deterioration due to cracks and the influence of residual stresses. A nonlinear, power law, of structure material is considered. General relationships for total participation of specific energies introduced in the structure by the loads, as well as for the critical participation have been proposed. On these bases: - a new strength calculation methods was developed; � strength of tubular cracked structures and of cracked tubular junction subjected to combined loading and strength were analyzed. Relationships for critical state have been proposed, based on dimensionless variables. These theoretical results fit with experimental date reported in literature. On the other side stress concentration coefficients were defined. Our one experiments onto a model of a pipe with two opposite nozzles have been achieved. Near one of the nozzles is a crack on the run pipe. Trough the experiments the state of stress have been obtained near the tubular junction, near the tip of the crack and far from the stress concentration points. On this basis the stress concentration coefficients were calculated.

Peculiarities of Formation of Residual Stresses in Welded Joints and Stellite Weld Cladding on Rail Steel

2020 ◽  
Vol 11 (3) ◽  
pp. 634-640
Author(s):  
S. Ya. Betsofen ◽  
K. V. Grigorovich ◽  
A. A. Ashmarin ◽  
A. Yu. Abdurashitov ◽  
M. A. Lebedev
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Rail Steel ◽  
Weld Cladding

Thermoacoustic method for relaxation of residual stresses in welded joints

1995 ◽  
Vol 30 (4) ◽  
pp. 491-493
Author(s):  
V. V. Koshovyi ◽  
M. I. Pekhn'o ◽  
O. I. Tsykhan
Keyword(s):  
Residual Stresses ◽  
Welded Joints

Finite Element Analyses of Residual Stresses in Typical Welded Joints Used in Nuclear Power Plants and Comparisons With Experiments

2010 ◽  
Author(s):  
Dean Deng ◽  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joints ◽  
Nuclear Power ◽  
Power Plants ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Dissimilar Metal ◽  
Water Reactors

Recent discoveries of stress corrosion cracking (SCC) at nickel-based metals in pressurized water reactors (PWRs) and boiling water reactors (BWRs) have raised concerns about safety and integrity of plant components. It has been recognized that welding residual stress is an important factor causing the issue of SCC in a weldment. In this study, both numerical simulation technology and experimental method were employed to investigate the characteristics of welding residual stress distribution in several typical welded joints, which are used in nuclear power plants. These joints include a thick plate butt-welded Alloy 600 joint, a dissimilar metal J-groove set-in joint and a dissimilar metal girth-butt joint. First of all, numerical simulation technology was used to predict welding residual stresses in these three joints, and the influence of heat source model on welding residual stress was examined. Meanwhile, the influence of other thermal processes such as cladding, buttering and heat treatment on the final residual stresses in the dissimilar metal girth-butt joint was also clarified. Secondly, we also measured the residual stresses in three corresponding mock-ups. Finally, the comparisons of the simulation results and the measured data have shed light on how to effectively simulate welding residual stress in these typical joints.

A Study of the Influence of Local Heat Treatment on the Structure of Welded Titanium Pipelines

2021 ◽  
Vol 410 ◽  
pp. 37-41
Author(s):  
Natalia A. Astafeva ◽  
Andrey A. Balanovskiy ◽  
Anna A. Pershina
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Titanium Alloys ◽  
Welded Joints ◽  
Treatment Method ◽  
Local Heat ◽  
Optical Metallography ◽  
Heat Treated ◽  
Weld Structure ◽  
Heat Treatment Method

The article analyzes the results of a study of the influence of zonal heat treatment on the structure of welded joints of pipeline elements made of titanium alloys Ti-3.5Al-1.5Mn. In the manufacture of such structures, the TIG welding method is used to join pipe elements, after which the heat treatment method can be used to relieve residual stresses. The experiments have confirmed the effectiveness of zonal heat treatment preceded by welding. It was revealed that for welded joints made of titanium alloys, heat treatment can stabilize the structure. In experiments conducted by the method of optical metallography, the structure of heat treated and untreated welded joints was investigated. The influence of heat treatment on the weld structure and heat-affected zone was identified.

Redistribution of residual stresses in explosion treatment of annular welded joints in a transmission pipeline

1997 ◽  
Vol 11 (7) ◽  
pp. 557-559
Author(s):  
A P Ammosov ◽  
S P Yakovleva ◽  
N I Golikov ◽  
A A Platonov ◽  
P P Petrov
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Transmission Pipeline
Sign in / Sign up

Export Citation Format

Share Document