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

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.

2018 ◽  
Vol 19 (01) ◽  
pp. 1940013 ◽  
Author(s):  
X. W. Ye ◽  
Y. H. Su ◽  
T. Jin ◽  
B. Chen ◽  
J. P. Han

The accuracy of fatigue life assessment for the welded joint in a steel bridge is largely dependent on an appropriate [Formula: see text]-[Formula: see text] curve. In this paper, a master [Formula: see text]-[Formula: see text] curve-based fatigue life assessment approach for the welded joint with an open-rib in orthotropic steel bridge deck is proposed based on the finite element model (FEM) and field monitoring data from structural health monitoring (SHM) system. The case studies on fatigue life assessment by use of finite element analysis (FEA) for constant-amplitude cyclic loading mode and field monitoring data under variable-amplitude cyclic loading mode are addressed. In the case of FEA, the distribution of structural stress at fatigue-prone weld toe is achieved using 4-node shell element model and then transformed into equivalent structural stress by fracture mechanics theory. The fatigue life of the welded joint is estimated with a single master [Formula: see text]-[Formula: see text] curve in the form of equivalent structural stress range versus the cycles to failure. In the case of monitoring data-based fatigue life assessment, the daily history of structural stress at diaphragm to U-rib is derived from the raw strain data measured by the instrumented fiber Bragg grating (FBG) sensors and transformed into equivalent structural stress. The fatigue life of the investigated welded joint is calculated by cyclic counting method and Palmgren–Miner linear damage cumulative rule. The master [Formula: see text]-[Formula: see text] curve method provides an effective fatigue life assessment process, especially when the nominal stress is hard to be defined. A single master [Formula: see text]-[Formula: see text] curve will facilitate to solve the difficulty in choosing a proper [Formula: see text]-[Formula: see text] curve which is required in the traditional fatigue life assessment methods.


Author(s):  
Michaël Martinez ◽  
Sébastien Montalvo

Abstract The mooring of floating platforms is an important challenge for the offshore industry. It is an important part of the design engineering and, often, a critical point for the fatigue life assessment. A solution that could improve the fatigue life is to directly connect the mooring rope to the platform, without an intermediate chain. However this solution is not widespread and the behavior of a rope near such a connection is little known. The present paper proposes to better understand this behavior, thanks to a detailed finite element model of the rope. The study case is a steel wire rope directly connected to a floating wind turbine. A local finite element model of the rope has been built, where the wires are individually modeled with beam elements. One end of the rope is clamped, simulating the connection, while tension and cyclic bending oscillations are applied to the other end. A localized bending takes place near the connection, leading to stress concentration in the wires. The stress concentration and the local contact forces are calculated for each wire. These data are important entry parameters for a local failure or fatigue analysis. This latter is however not presented here. Despite IFPEN experience in the development of local finite element models of steel wire ropes, it is the first time that such a high capacity rope (MBL = 12 500 kN) is modeled. This is challenging because of the large diameter of the rope and the large number of wires. However this modeling approach is very valuable for such ropes, because the experimental tests are rare and very expensive.


2012 ◽  
Vol 151 ◽  
pp. 484-489 ◽  
Author(s):  
Jie Fang Xing ◽  
Jie Zhang ◽  
Lu Jun He

Introduce some basic knowledge, methods and theory of using the finite element software ANSYS to carry out contact analysis, and then establish the contact simulation analysis finite element model for CTP imaging drum and plate by using the software ANSYS. A numerical simulation analysis on the imaging drum and the plate indicates that the analysis results are consistent with the experimental results, so as to lay the foundation for the reliability and stability of dynamic design and optimization design of CTP imaging drum.


Author(s):  
Yong Bai ◽  
Jiannan Zhao ◽  
Xinyu Sun ◽  
Xiaojie Zhang ◽  
Zhao Wang

Abstract Fiber glass reinforced flexible pipe (FGRFP) is a kind of submarine pipe widely used in oil and gas transportation and exploration. This paper mainly studies the theoretical and numerical simulation methods for calculating the fatigue life of the FGRFP. Firstly, the tension time-histories and bending moment time-histories of the FGRFP are obtained by using global analysis. The tension and bending moment frequency distribution histograms are obtained by using rain flow method. Then, the finite element software ABAQUS is used to build the model of the FGRFP, and the corresponding tension and bending moment are applied on the finite element model. Then, the stress time histories curve of the FGRFP is obtained. By comparing the results of numerical simulation, the main factors affecting the fatigue life of the FGRFP are studied. Finally, according to rain flow method, S-N curve and numerical simulation results, the fatigue life and single damage rate of FGRFP are obtained.


Author(s):  
Tao Wang ◽  
Liangmo Wang ◽  
Yuanlong Wang

In this paper, fatigue damage analysis and structural improvement of a commercial vehicle cab were carried out, in which a simulation technique and durability road tests were combined. A full-scale finite element model of the cab was established and then validated by means of physical testing and analysis of its stiffness and its modal performance. The loading spectra, in accordance with the durability road test, were obtained by adopting the virtual iteration method. With the established finite element model, the stress distributions in the cab under unit excitation were determined. The obtained stress distributions were then used to assess the total fatigue life of the cab by employing the strain–life ( ε–N) method; thus, the critical regions were determined. The results showed that some components near the pillars and mounts are easy to damage because of the stress concentrations. It was also demonstrated that the predicted regions are reliable, which was verified by comparison with the physical durability road tests. Finally, structural improvements in the critical structures were made; the fatigue life assessment of the improved cab showed an obvious improvement in its durability performance.


2015 ◽  
Vol 750 ◽  
pp. 153-159
Author(s):  
Jie Dong ◽  
Xue Dong Chen ◽  
Bing Wang ◽  
Wei He Guan ◽  
Tie Cheng Yang ◽  
...  

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.


2013 ◽  
Vol 838-841 ◽  
pp. 458-461
Author(s):  
Jing Cui ◽  
Ling Feng Yin ◽  
Xiao Ming Guo ◽  
Gan Tang ◽  
Tian Jiao Jin

Based on the fire tests of WILLIAMS double-poles structure, considering the dual nonlinear interaction of material and geometric, established one complete finite element model of grid structure. For the performance that the physical and mechanics properties of steel will degrade while the temperature arising, simulate the test models with ANSYS, get a better numerical results, proof the numerical method is feasible.


2012 ◽  
Vol 443-444 ◽  
pp. 751-756
Author(s):  
Li Jun Suo ◽  
Xia Guang Hu

In China, it is fact that porous concrete base has been used in the construction of asphalt pavement in recent years because porous concrete base has good performance. However, Reasonable design method has not been put forward so far. Therefore, it is necessary to analyze load stress and thermal stress of asphalt pavement which includes porous concrete base in order to put forward theoretical basis for pavement design method. In the paper, three–dimension finite element model of asphalt pavement, which includes porous concrete base and asphalt surface, is created for the purpose of studying load stress and thermal stress of porous concrete base in asphalt pavement. Based on numerical method of three–dimension finite element model, finite element software, such as ANSYS, is employed to study load stress and thermal stress of porous concrete base in asphalt pavement. After that, the effect of different factors on stress is studied, and the factors include thickness of surface, thickness of base and ratio of base’s modulus to foundation’s modulus. Finally, calculation results for stress are compared with each other, and it shows that load stress of porous concrete base decreases with increase of base’s thickness, while thermal stress of porous concrete base increases with increase of base’s thickness. Load stress and thermal stress of porous concrete base decrease with increase of surface’s thickness. Load stress and thermal stress of porous concrete base increase with increase of ratio of base’s modulus to foundation’s modulus.


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