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.

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.

Mechanical properties of a dissimilar aluminum alloy joint welded by hybrid laser–MIG welding

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744037 ◽  
Author(s):  
Qiuying Wang ◽  
Hui Chen ◽  
Zongtao Zhu ◽  
Yunlong Cui
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Welded Joint ◽  
Probability Of Failure ◽  
Dissimilar Joint ◽  
Mig Welding ◽  
Welded Structure ◽  
Fatigue Data ◽  
Service Conditions ◽  
The Mean

Two dissimilar Al alloys, 5083-H111 and 6005A-T6, were joined by hybrid laser–MIG welding method. Mechanical properties of the welded joint were investigated and compared. The results show that the tensile strength of the dissimilar joint is 219.8 MPa, 11.7% higher than that of 6005A-T5 joint. After statistical analysis of the fatigue data, the [Formula: see text]–[Formula: see text]–[Formula: see text] curves of the dissimilar joint were obtained. The mean fatigue strength at [Formula: see text] of the dissimilar joint is 112.5 MPa. The fatigue strength at [Formula: see text] of the dissimilar joint for a given 10% probability of failure, at a confidence level of 95%, is 101.4 MPa. The fatigue strength at [Formula: see text] of the dissimilar joint is almost same as that of the 6005A-T6 joint. In welded structure designing, different [Formula: see text]–[Formula: see text]–[Formula: see text] curves should be chosen according to the different service conditions and reliability requirements.

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.

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.

Resonant Fatigue Testing of Cantilever Specimens Prepared from Thin Films

2008 ◽  
Vol 1139 ◽  
Author(s):  
Kwangsik Kwak ◽  
Masaaki Otsu ◽  
Kazuki Takashima
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Cantilever Beam ◽  
Microelectromechanical Systems ◽  
Fatigue Testing ◽  
Crystalline Silicon ◽  
Gold Foil ◽  
Fatigue Properties ◽  
Mems Devices ◽  
Testing Method

AbstractFatigue properties of thin film materials are extremely important to design durable and reliable microelectromechanical systems (MEMS) devices. However, it is rather difficult to apply conventional fatigue testing method of bulk materials to thin films. Therefore, a fatigue testing method fitted to thin film materials is required. In this investigation, we have developed a fatigue testing method that uses a resonance of cantilever type specimen prepared from thin films. Cantilever beam specimens with dimensions of 1(W) × 3(L) × 0.01(t) mm3 were prepared from Ni-P amorphous alloy thin films and gold foils. In addition, cantilever beam specimens with dimension of 3(L) × 0.3(W) × 0.005(t) mm3 were also prepared from single crystalline silicon thin films. These specimens were fixed to a holder that is connected to an golddio speaker used as an actuator, and were resonated in bending mode. In order to check the validity of this testing method, Young's moduli of these specimens were measured from resonant frequencies. The average Young's modulus of Ni-P was 108 GPa and that of gold foil specimen was 63 GPa, and these values were comparable with those measured by other techniques. This indicates that the resonance occurred theoretically-predicted manner and this testing method is valid for measuring the fatigue properties of thin films. Resonant fatigue tests were carried out for these specimens by changing amplitude range of resonance, and S-N curves were successfully obtained.

Cyclic and High Strain Behavior of Titanium Alloys Used for Riser Components

2008 ◽  
Author(s):  
C. F. G. Baxter
Keyword(s):  
Stress Relaxation ◽  
Titanium Alloys ◽  
Elevated Temperatures ◽  
Fatigue Testing ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
Fatigue Data ◽  
Stress Ratios

Grades 23 and 29 titanium alloys are becoming more commonly used offshore for critical components of riser systems. Many of these components, such as compact flanges, operate at high mean strains due to make-up loads, often close to or above yield. Hitherto, weld fatigue data collected at low mean strains have been used for prediction of fatigue lives of such components. However, these analyses have resulted in short but adequate lives. The objective of this work was, therefore, to derive fatigue data that could be applied to components operating at high strains and over a large range of stress ratios. This necessitated strain-controlled fatigue testing. Cyclic material properties evaluated from the tests are presented. In addition, it was found that sustained strain load, a type of stress relaxation that, unlike normal stress relaxation, does not require elevated temperatures, affected the cyclic behavior It also affects the distribution of make up stresses. This phenomenon was also investigated and it was shown that the cyclic stress/strain curve, readily derived from strain-controlled fatigue tests, accounted for sustained strain load effects.

Fretting Fatigue Design of Subsea Connectors: A Generalised Approach to Testing

2020 ◽  
Author(s):  
H. Andresen ◽  
D. A. Hills ◽  
Anders Wormsen ◽  
K. A. Macdonald
Keyword(s):  
Crack Nucleation ◽  
Normal Load ◽  
Asymptotic Methods ◽  
Fretting Fatigue ◽  
Test Design ◽  
Frictional Contacts ◽  
Fatigue Design ◽  
Geometrical Features ◽  
Fatigue Data ◽  
Constant Normal Load

Abstract In this paper fretting fatigue is addressed as a potential design consideration for wellhead connectors. The study of near-edge relative motion for frictional contacts under constant normal load is described using analytical, numerical and asymptotic methods. Based on published fretting fatigue experimental data an argument is drawn for a generalised fretting fatigue test design. We do this by reducing the parameters responsible for crack nucleation to the smallest number possible and thereby revealing the fretting fatigue strength as a material property independent of geometrical features. Easy to apply recipes are described and thoughts on a potential apparatus are shared with the reader. Commercial potential lies in the wide-ranging applicability of experimental results across many prototypes and loadings once an appropriate amount of fretting fatigue data has been generated for the material in question.

Sign in / Sign up

Export Citation Format

Share Document