Fatigue design of welded joints and components

1996 ◽  
Author(s):  
A Hobbacher
Keyword(s):  
Welded Joints ◽  
Fatigue Design

Fatigue Assessment of Welded Joints Taking Into Account Effects of Residual Stress

2010 ◽  
Author(s):  
Nur Syahroni ◽  
Stig Berge
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Welded Joints ◽  
Fatigue Testing ◽  
International Association ◽  
Hot Spot ◽  
Mean Stress ◽  
Element Analysis ◽  
Structural Rules ◽  
Fatigue Design

Residual stress may have a significant effect on the fatigue strength of welded joints. As a non-fluctuating stress, it has an effect similar to that of the mean stress. Recently the International Association of Ship Classification Societies (IACS) has issued Common Structural Rules (CSR) for respectively tankers (IACS 2006a) and bulk carriers (IACS 2006b). The effect of mean stress in fatigue design is taken into account in both sets of rules. However, the treatment is quite different, in particular with regard to residual stress and shakedown effects. In the present paper a comparative study of fatigue design procedures of the IACS rules is reported, with emphasis on residual stress effects. Testing was carried out with longitudinal attachment welds in the as-welded condition. The initial residual stress was measured by a sectioning method using strain gages. Hot spot stress was determined experimentally by strain gauges and numerically by finite element analysis using different types of elements. Fatigue testing was carried out and SN-curves were plotted according to the relevant stress as specified by the rules. In order to investigate the shake-down effect of residual stress, testing was performed for several pre-load conditions which could be taken to represent maximum load levels in a load history. The aim of the study is to contribute towards better understanding of the effect of residual stress and shakedown on fatigue strength of welded joints.

Differences in Fatigue Strength Between Arc and Laser Hybrid Welded Joints

2008 ◽  
Vol 24 (03) ◽  
pp. 139-146
Author(s):  
H. Remes ◽  
P. Varsta
Keyword(s):  
Fatigue Strength ◽  
Welded Joints ◽  
Fatigue Tests ◽  
Notch Depth ◽  
Butt Joints ◽  
Fatigue Design ◽  
Notch Stress ◽  
Notch Geometry ◽  
Laser Hybrid ◽  
Fatigue Endurance

This paper presents the results of fatigue tests, including tests of laser hybrid and arc welded butt joints, for two plate thicknesses, 6 and 12 mm. Pure laser welded joints were also tested. The S-N curves based on nominal stresses for the different welded joints are presented. The results were further analyzed using the notch stress approach, where the fatigue notch factors were determined from the measured geometries of the welded joints. Unexpected differences in the S-N curves based on the notch stresses were found between the laser hybrid and arc welded joints and between the laser hybrid and pure laser welded joints. The reasons for this difference were studied with the help of extensive measurements of weld notch geometries. Significant differences in the geometries were observed. Taking into account the notch geometry and the notch depth, the notch stress approach partially explains the differences between the fatigue endurance limits of the laser hybrid and arc welded joints. The applicability of the notch stress approach to the fatigue design of laser hybrid welded joints is also discussed.

Influence of Welding Residual Stresses on Fatigue Design of Welded Joints and Components

2007 ◽  
Vol 51 (7-8) ◽  
pp. 54-68 ◽  
Author(s):  
J. Krebs ◽  
M. Kassner
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Fatigue Design

scholarly journals A Fracture Mechanics-Based Optimal Fatigue Design Method of Under-Matched HSLA Steel Butt-Welded Joints with Imperfections

2019 ◽  
Vol 9 (17) ◽  
pp. 3609 ◽  
Author(s):  
Wen ◽  
Wang ◽  
Dong ◽  
Fang
Keyword(s):  
Fracture Mechanics ◽  
Welded Joints ◽  
Design Method ◽  
Hsla Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Engineering Structures ◽  
Fatigue Design ◽  
Load Carrying ◽  
Practical Engineering

The trend of light-weight structures leads to the wide application of high strength steels in engineering structures. When welding high strength steels, under-matched consumables could reduce the cold-cracking tendency, simplifying the preheating process. However, under-matched welds would sometimes make the high strength base metal pointless due to its weak load-carrying capacity. For the purpose of enhancing the fatigue strength of under-matched welded joints, a fracture mechanics-based optimal fatigue design method of under-matched butt-welded joints is proposed in this work. Heterogeneous mechanical features of welded joints, which are not considered in current standards and codes, are incorporated into the optimal design method. The fatigue limit of the high strength parent metal is taken as the design target, which has seldom been reported. HSLA steel Q550, with its under-matched consumable ER70S-6 composed X-shaped butt-welds, is selected for experimental verification. The experimental results indicate that the fracture mechanic based equal-fatigue-bearing-capacity (EFBC) design method established in this work is feasible and could be a valuable reference for the design of practical engineering structures.

Sign in / Sign up

Export Citation Format

Share Document