Numerical Simulation on Fatigue Life Assessment of Free Span for Submarine Pipeline

2015 ◽  
Vol 750 ◽  
pp. 153-159
Author(s):  
Jie Dong ◽  
Xue Dong Chen ◽  
Bing Wang ◽  
Wei He Guan ◽  
Tie Cheng Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fatigue Life ◽  
Oil And Gas ◽  
Structural Response ◽  
Simulation Method ◽  
Life Assessment ◽  
Response Analysis ◽  
Submarine Pipeline ◽  
Fatigue Life Assessment ◽  
Harmonic Response Analysis

The upper and lower courses of sea oil and gas exploitationare connected by submarine pipeline which is called life line project. Free span often occurs because of the unevenness and scour of seabed, and fatigue is one of the main failure modes.In this paper, with the finite element numerical simulation method, based on the harmonic response analysis, the research on the structural response of free span under the vibration induced by vortex was investigated, and the effect of the factors such as flow velocity, length of free span. According to the analysis results,the fatigue life of free span was evaluated.

The Research on the Effect of the Height of Free Span on Fatigue Life of Submarine Pipeline due to Vortex-Induced Vibration

2016 ◽  
Author(s):  
Jie Dong ◽  
Chen Xuedong ◽  
Bing Wang ◽  
Weihe Guan ◽  
Zhichao Fan ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Lift Coefficient ◽  
Structural Response ◽  
Life Assessment ◽  
Submarine Pipeline ◽  
The Finite Element Method ◽  
Fatigue Load ◽  
Critical Height ◽  
Vortex Induced Vibration ◽  
Fatigue Life Assessment

Free span is a risk of security of submarine pipelines. Fatigue caused by vortex-induced vibration (VIV) is a main failure mode of free spans. The height of free span which influences the VIV fatigue load is an important factor for the fatigue life assessment. In this paper, taking an in-service submarine pipeline as an example, the relation between the height and the fluctuating lift coefficient was firstly investigated by the method of computational fluid dynamics, and the critical height which can neglect its effect on the coefficient was obtained. The VIV structural response of free span with different height and length was analyzed with the finite element method. Furthermore, considering the in-service environment of the submarine pipeline, fatigue life of free span was evaluated numerically with reference to the measured data of flow velocity and its variation with time. Those results provide technical support for the maintenance of free span for the submarine pipeline.

scholarly journals Numerical Simulation of Fatigue Performance of Diaphragm of Large-Span Bridge Orthotropic Deck

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Hui Li ◽  
Bo Zhao ◽  
Han Zhu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Fatigue Life ◽  
Finite Element Model ◽  
Element Model ◽  
Life Assessment ◽  
Steel Bridge ◽  
Large Span ◽  
Finite Element Software ◽  
Fatigue Life Assessment

Under traffic loads, orthotropic steel bridge slabs suffer from an obvious fatigue problem. In particular, fatigue cracking of diaphragms seriously affects application and development of orthotropic bridge slabs. In the paper, based on cracking status quo of an orthotropic deck diaphragm of a large-span bridge, experimental tests were formulated to test stress distribution states of the diaphragm. The finite element software ABAQUS was used to establish a finite element model of the orthotropic deck diaphragm; numerical simulation was conducted on the basis of the experiments. Simulation results were compared with experimental results, so correctness of the finite element model was verified. Finally, Local Strain Approach (LSA) and Theory of Critical Distance (TCD) were used to conduct life assessment of the orthotropic deck diaphragms, and applicability of two methods was discussed. In this way, a fatigue life assessment method with high accuracy and good operability was provided for fatigue life assessment of orthotropic deck diaphragms.

scholarly journals Mapping of scatter in fatigue life assessment of welded structures—a round-robin study

2021 ◽  
Author(s):  
Gustav Hultgren ◽  
Mansoor Khurshid ◽  
Peter Haglund ◽  
Zuheir Barsoum
Keyword(s):  
Fatigue Life ◽  
Round Robin ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Fatigue Life Estimation ◽  
Box Structures ◽  
Load Carrying ◽  
Local Stresses ◽  
Sources Of Variation ◽  
Global And Local

AbstractA round-robin study has been carried out within a national project in Sweden with the addition of an international participant, where several industrial partners and universities are participating. The project aims to identify variation and sources of variation in welding production, map scatter in fatigue life estimation, and define and develop concepts to reduce these, in all steps of product development. The participating organisations were asked to carry out fatigue life assessment of welded box structures, which is a component in load-carrying structures. The estimations of fatigue life have also been compared with fatigue test results. Detailed drawings, loads and material data were also given to the participants. The participants were supposed to use assessment methods based on global and local stresses using the design codes or recommendations they currently use in-house. Differences were identified between both methods and participants using the same codes/recommendations. Applicability and conditions from the cases in the codes were also identified to be differently evaluated between the participants. It could be concluded that for the applied cases the nominal stress method often overestimated the fatigue life and had a high scatter in the estimations by different participants. The effective notch method is conservative in comparison to the life of tested components with little scatter between the results derived by the participants.

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