A continuum model for damage evolution simulation of the high strength bridge wires due to corrosion fatigue

2018 ◽  
Vol 146 ◽  
pp. 76-83 ◽  
Author(s):  
Bin Sun
2019 ◽  
Vol 2019 ◽  
pp. 1-24 ◽  
Author(s):  
Ying Wang ◽  
Yuqian Zheng

Corrosion fatigue (CF) failure is one of the typical failure modes of high-strength steel wires for bridge cables because the cables are subjected to long-term fatigue loads and exposed to heavily polluted environment simultaneously. In this paper, a numerical simulation method was proposed to study CF performance of corroded high-strength steel wires. Firstly, the cellular automata (CA) method was used to generate a numerical model of corroded steel wires with corrosion pit, which can accurately describe the electrochemical process of metal corrosion. In the established CA model, three kinds of cells were involved, namely, metal cell, passive film cell, and corrosive medium cell. By setting 10 cellular transformation rules, morphology of the random corrosion pit on the steel wire surface was simulated. And then, a damage evolution model related to coupling of corrosivemedium and fatigue loads (CCF) was developed to describe the CF damage evolution process of steel wires. Subsequently, the damage evolution process was analyzed by ABAQUS with a user-defined material subroutine (UMAT). Finally, the life of corroded steel wires was predicted, and the CF performance of corroded steel wires with multiple corrosion pits was evaluated. The results show that the proposed method can reasonably describe the CF damage evolution process and illuminate the failure mechanism of steel wires subjected to the CCF. Damage of the steel wire with a single corrosion pit evolves gradually, and the damage evolution rate increases. For the steel wires with multiple corrosion pits, the corrosion pits affect mutually in the fracture process. When the angle and distance between corrosion pits reach a certain degree, the mutual effects can be ignored. With the same pit depth, the angle and distance among corrosion pits determine the CF life of steel wires mainly, and the number of corrosion pits affects slightly.


2019 ◽  
Vol 29 (6) ◽  
pp. 887-901 ◽  
Author(s):  
Chen Fan ◽  
Zhaoxia Li ◽  
Ying Wang

Cables are the most sensitive components in cable-supported bridges, and the failure of cables is usually caused by the degradation of mechanical properties of internal wires. Based on Faraday's law and the rates of microcrack initiation and propagation, a multi-scale corrosion fatigue damage model was developed to describe the damage evolution in the stages of pit growth and microcrack propagation. The accuracy and effectiveness of this damage model were also verified through the experimental data of corrosive fatigue life of high-strength bridge wires. The result shows that this damage model can describe the multi-scale corrosion fatigue damage evolution process of high-strength bridge wires reasonably and effectively, which provides a new way to better understand the trans-scale damage evolution mechanism during the corrosion fatigue process of high-strength bridge wires.


2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Gabriel Rombado ◽  
David A. Baker ◽  
Lars M. Haldorsen ◽  
Pedro da Silva Craidy ◽  
Jim H. Feiger ◽  
...  

Abstract Design of a steel catenary riser requires the use of connection hardware to decouple the large bending moments induced by the host floater at the hang-off location. Reliability of this connection hardware is essential, particularly in applications involving high pressure and high temperature fluids. One option for this connection hardware is the metallic tapered stress joint. Titanium (Ti) Grade 29 has been identified as an attractive material candidate for demanding stress joint applications due to its “high strength, low weight, superior fatigue performance and innate corrosion resistance”.2 Titanium stress joints for deepwater applications are typically not fabricated as a single piece due to titanium ingot volume limitations, thus making an intermediate girth weld necessary to satisfy length requirements. As with steel, the potential effect of hydrogen embrittlement induced by cathodic and galvanic potentials must be assessed to ensure long-term weld integrity. This paper describes testing from a joint industry project (JIP) conducted to qualify titanium stress joint (TSJ) welds for ultra-deepwater applications under harsh service and environmental conditions. Corrosion-fatigue crack growth rate (CFCGR) results for Ti Grade 29 flat welding-groove weld (1G/PA) gas tungsten arc welding (GTAW) specimens in seawater under cathodic potential and sour brine under galvanic potential are presented and compared to vendor recommended design curves.


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