Codes and Practice of Fatigue Design for Welded Structures

1999 ◽  
Author(s):  
Haruo Sakamoto
Keyword(s):  
Statistical Study ◽  
Welded Joint ◽  
Fatigue Testing ◽  
Fracture Probability ◽  
Structural Stress ◽  
Welded Structures ◽  
Testing Method ◽  
Japanese Industrial Standard ◽  
Fatigue Design ◽  
Fatigue Data

Abstract This paper describes the codes and practice for designing welded structures such as railroad truck frames. For designing the first configuration, rather simple criteria are desired, although most codes such as AWS. AISC, etc. are complex. They consist of a variety of welded joint categories, which make a designer feel uncomfortable when deciding the first configuration. Therefore, such codes are considered to be mainly used for the evaluation of designed and constructed structures, and not to be used for deciding the first configuration. The JIS (Japanese Industrial Standard) for a railroad truck frame is explained as an example of a simple code, and is compared with some fatigue data. This standard is thought to be useful for a designer. However, the result of this investigation suggests a modification of the JIS for obtaining more reasonable criteria. Desirable criteria should be simple for a designer and sufficiently safe for structures. Additional investigations on fatigue data of welded joints, a statistical study for desirable non-fracture probability, and methods of structural stress analysis are to be conducted in the future. A practical fatigue testing method is also needed for investigating the strength in a high cycle region such as 108.

Codes and Practice of Fatigue Design for Welded Structure

2007 ◽  
Vol 353-358 ◽  
pp. 2828-2831
Author(s):  
Haruo Sakamoto
Keyword(s):  
Statistical Study ◽  
Welded Joint ◽  
Fatigue Testing ◽  
Fracture Probability ◽  
Initial Configuration ◽  
Testing Method ◽  
Japanese Industrial Standard ◽  
Fatigue Design ◽  
Welded Structure ◽  
Fatigue Data

This paper describes codes and practice for designing welded structures such as railroad truck frames. For designing an initial configuration, rather simple criteria are desired, although most codes such as AWS, AISC, etc. are complex. They consist of a variety of welded joint categories, which make a designer feel difficult when deciding the initial configuration. Therefore, such codes are considered to be mainly used for the evaluation of designed and constructed structures, and not to be used for deciding the initial configuration. The JIS (Japanese Industrial Standard) for a railroad truck frame is explained as an example of a simple code, and is compared with some fatigue data. This standard is thought to be useful for a designer. However, the result of this investigation suggests a modification of the JIS for obtaining more reasonable criteria. Desirable criteria should be simple for a designer and sufficiently safe for structures. Additional fatigue data of welded joints, a statistical study for desirable non-fracture probability, and methods of structural stress analysis are to be researched in the future. A practical fatigue testing method is also needed for investigating the strength in a high cycle region such as 108.

Fatigue of Tubular Joints: Hot Spot Stress Method Revisited

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Pingsha Dong ◽  
Jeong K. Hong
Keyword(s):  
Hot Spot ◽  
Life Assessment ◽  
Structural Stress ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Fatigue Design ◽  
Fatigue Data ◽  
Section Viii ◽  
Remaining Life Assessment

A series of well-known tubular joints tested in UKSORP II have been re-evaluated using the mesh-insensitive structural stress method as a part of the on-going Battelle Structural Stress JIP efforts. In this report, the structural stress based analysis procedure is first presented for applications in tubular joints varying from simple T joints, double T Joints, YT joints with overlap, and K joints with various internal stiffening configurations. The structural stress based SCFs are then compared with those obtained using traditional surface extrapolation based hot spot stress methods. Their abilities in effectively correlating the fatigue data collected from these tubular joints are demonstrated. These tests are also compared with the T curve typically used for fatigue design of tubular joints as well as the structural stress based master S-N curve adopted by ASME Section VIII Div 2. Finally, some of the implications on fracture mechanics based remaining life assessment for tubular joints are discussed in light of the results obtained in this investigation.

Fatigue Analysis of Titanium Welded Joints Using Mesh-Insensitive Structural Stress Approach

2011 ◽  
Vol 66-68 ◽  
pp. 838-844
Author(s):  
Li Bin Fu ◽  
Xin Hua Yang ◽  
Ping Sha Dong ◽  
Rui Ming Ren
Keyword(s):  
Welded Joints ◽  
Fatigue Crack Initiation ◽  
Structural Stress ◽  
Characteristic Analysis ◽  
Fatigue Characteristic ◽  
Welded Structures ◽  
Fatigue Data ◽  
Stress States ◽  
First Time ◽  
Better Than

Mesh-insensitive structural stress approach is a robust method for fatigue characteristic analysis of welded structures and has been validated in correlating a large amount of published fatigue test of steel welded joints in the literature. Regarding Titanium welded joints, the combination of stress states and geometric shape can also lead to stress concentration that can result in fatigue crack initiation around the welded joints. This paper aims to analyze well-documented fatigue data of transverse and longitudinal fillet welded joints of Titanium using mesh-insensitive structural stress approach. This study is the first time using the approach for titanium fatigue data analysis. The results show that the employed method can correlate fatigue data of Titanium welded joints noticeably and make sense to understand the effect of thickness on fatigue life of the joints better than conventional methods.

Fatigue Design of the Railroad Car Body Member Using a Simulated Single Spot Welded Joint

2007 ◽  
Vol 353-358 ◽  
pp. 2809-2811
Author(s):  
Dong Ho Bae ◽  
Sol Bin Lee ◽  
Sun Kyu Park
Keyword(s):  
Fatigue Strength ◽  
Welded Joint ◽  
Design Method ◽  
Lap Joints ◽  
Design Criterion ◽  
Single Spot ◽  
Car Body ◽  
Fatigue Design ◽  
Fatigue Data ◽  
Spot Welded

In order to develop a fatigue design method for the actual railroad car body structures using the fatigue data on simulated single spot welded lap joints, firstly, evaluated fatigue strength on the spot welded t-type member which is a component of the actual railroad car body structure. And next, possibility of fatigue design for spot welded T-type member using the fatigue data of single spot welded lap joints was investigated. From the results, it was found that, even though there is some difference in fatigue strength between single spot welded joint and the actual members under the same fatigue life, the fatigue design criterion could be predicted by correction between them.

Fatigue of Tubular Joints: Hot Spot Stress Method Revisited

2008 ◽  
Author(s):  
Pingsha Dong ◽  
Jeong K. Hong
Keyword(s):  
Hot Spot ◽  
Life Assessment ◽  
Structural Stress ◽  
T Joints ◽  
Hot Spot Stress ◽  
Tubular Joints ◽  
Fatigue Design ◽  
Fatigue Data ◽  
Section Viii ◽  
Remaining Life Assessment

A series of well-known tubular joints tested in UKSORP II have been re-evaluated using the mesh-insensitive structural stress method as a part of the on-going Battelle Structural Stress JIP efforts. In this report, the structural stress based analysis procedure is first presented for applications in tubular joints varying from simple T joints, double T Joints, YT joints with overlap and K joints with various internal stiffening configurations. The structural stress based SCFs are then compared with those obtained using traditional surface extrapolation based hot spot stress methods. Their abilities in effectively correlating the fatigue data collected from these tubular joints are demonstrated. These tests are also compared with the T curve typically used for fatigue design of tubular joints as well as the structural stress based master S-N curve adopted by ASME Section VIII Div 2. Finally, some of the implications on fracture mechanics based remaining life assessment for tubular joints are discussed in light of the results obtained in this investigation.

Efficient Fatigue Testing of Tubular Joints

2015 ◽  
Author(s):  
P. Thibaux ◽  
J. Van Wittenberghe ◽  
E. Van Pottelberg ◽  
M. Van Poucke ◽  
P. De Baets ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Tubular Joints ◽  
Testing Method ◽  
Out Of Plane ◽  
Resonance Principle ◽  
Tubular Joint ◽  
The Cost ◽  
Good Agreement

Tubular joints are intensively used in off-shore structures for shallow waters. Depending on the sea conditions and the type of structure, the design can be fatigue driven. This is particularly the case for off-shore wind turbines, where turbulences are generating a fatigue loading. Any improvement of the fatigue performance of the tubular joint would be beneficial to reduce the weight and the cost of the structure. To assess efficiently the fatigue resistance of the tubular joint, a testing method has been developed based on the resonance principle. The complete circumference of the welded joint can be loaded, successively in the in-plane and out-of-plane modes at a frequency close to 20Hz. Finite element computations were used to investigate the feasibility of the concept. Then, an X-node was made and successfully tested to investigate the stress distribution along the weld. The experimental results were compared with finite element computations, giving a good agreement.

A Comparative Study on Infrared Thermography during Ultrasonic Fatigue Testing of Cast Steel 42CrMo4 and Cast Aluminium Alloy AlSi7Mg

2013 ◽  
Vol 592-593 ◽  
pp. 501-504 ◽  
Author(s):  
Dominik Krewerth ◽  
Anja Weidner ◽  
Horst Biermann
Keyword(s):  
Aluminium Alloy ◽  
Infrared Thermography ◽  
Fatigue Testing ◽  
Cast Steel ◽  
Material Testing ◽  
Initiation Point ◽  
Testing Method ◽  
Cast Aluminium ◽  
Ultrasonic Fatigue ◽  
Non Destructive

The present paper illustrates a comparison of infrared thermography during ultrasonic fatigue testing of cast steel 42CrMo4 and cast aluminium alloy AlSi7Mg. Against the background of different material properties (e.g. mechanical properties as well as thermal properties) the benefit of this non-destructive material testing method in terms of determining the crack initiation point and time during fatigue testing as well as crack propagation is evaluated and discussed. Moreover, correlations between fractography and infrared thermography are performed for both materials.

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.

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