scholarly journals Fatigue Life Characteristics of Segmental Lining Structure for the Shallow Buried Metro Tunnel under the Dynamic Load of a High-Speed Railway

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Qing Zhao ◽  
Bingrong Pu ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Dynamic Load ◽  
High Speed ◽  
Dynamic Loads ◽  
High Speed Railway ◽  
Segmental Lining ◽  
Lining Structure ◽  
Metro Tunnel

Shallow buried shield metro tunnels constructed underneath subgrade project of high-speed railways are becoming increasingly common in China, but the lower metro tunnel bears the fatigue effect of dynamic load induced by the upper high-speed railway, so the long-term durability of segmental lining is a nonnegligible problem. The segmental lining structure of metro tunnel is in a state of static-dynamic loads for a long time, especially when a high-speed railway passes above the metro line, and the long-term durability of segmental lining needs further research. Based on theoretical analysis, the effect of different forms of loads on the fatigue life was analyzed, the change law of the static-dynamic loads on segmental lining was summarized, and the method was put forward to evaluate the fatigue life characteristics of segmental lining. The research results reveal that the additional dynamic load is the fundamental reason for the fatigue failure of the structure, and the existence of static load can cause and accelerate the occurrence of structural fatigue failure simultaneously. The results indicate that the fatigue life decreases gradually with the increase of static-dynamic load. Based on coupling analysis of static-dynamic loads of segmental lining, the fatigue life increases first and then decreases with the increase of buried depth of metro tunnel, and it remains unchanged when the depth exceeds a certain value. According to the actual metro tunnel engineering, by using ABAQUS software, a three-dimensional numerical simulation was carried out to analyze the characteristics of the fatigue life and evolution rules of segmental lining. Based on the modified fatigue life formula and metro service life, the optimization design of the buried depth was carried out to determine the most reasonable range of the buried depth. This study provides a valuable reference for safe operation and long-term durability of metro tunnels under high-speed railways.

Calculation Error Analysis on the Strain Fatigue Life Predication Formula of Manson-Coffinn and Damage Stain Model

2011 ◽  
Vol 197-198 ◽  
pp. 1599-1603
Author(s):  
Zhen Wei Wang ◽  
Ping An Du ◽  
Ya Ting Yu
Keyword(s):  
Fatigue Life ◽  
Error Analysis ◽  
Fatigue Failure ◽  
High Speed ◽  
Production Cost ◽  
Calculation Error ◽  
Mechanical Components ◽  
Strain Model ◽  
Engine Crankshaft

Mechanical components are subjected heavy alternate load in industries, such as engine crankshaft, wheel axle, etc. The fatigue failure happens after a long work loading, which affects the production cost, safe and time. So the fatigue life predication is fundamental for the mechanical components design. Especially, it is very important for heavy, high-speed machinery. In this paper, both main fatigue life predication formulas are introduced briefly, including Manson-Coffinn formula and Damage strain model. Then, shortages of above life predication formulas are pointed out, and coefficients are explained in detail. Further calculation error analysis is conducted on the basis of experiments on 16 materials. Results show that above life predication formulas lack calculation accuracy. Finally, it is pointed out that coefficients of fatigue life predication formulas are dependent of material performance. So it is unreliable that coefficients are constants for Manson-Coffin and Damage strain model.

How to balance interfirm relationships? A case from high-speed railway industry

2020 ◽  
Vol 35 (11) ◽  
pp. 1785-1799 ◽  
Author(s):  
Na Zhang ◽  
Xiaopeng Deng ◽  
Bon-Gang Hwang ◽  
Yanliang Niu
Keyword(s):  
High Speed ◽  
Superior Performance ◽  
Interfirm Relationships ◽  
High Speed Railway ◽  
Content Type ◽  
Railway Industry ◽  
Interfirm Cooperation ◽  
Relationship Structures ◽  
Interfirm Competition

Purpose Balancing interfirm relationships is important for firms’ long-term superior performance. However, prior studies mainly focus on interfirm competition or interfirm cooperation separately, ignoring the balance of interfirm relationships. To bridge this gap in knowledge, this study aims to develop a framework to evaluate the balance of interfirm competition and interfirm cooperation and propose strategies to optimize a firm’s interfirm relationships. Design/methodology/approach After an in-depth literature review, a framework was developed for evaluating and optimizing the interfirm relationships. Taking the high-speed railway industry as an example, the proposed framework was implemented. Findings The results of the case confirm that the balancing of interfirm relationships can lead to more superior firm performance. Also, rather than mutual suppression, the interfirm competition and interfirm cooperation present a roughly positive relationship. Originality/value This study would contribute to the existing knowledge body by developing a framework for balancing interfirm relationships. Also, this study can aid practitioners in evaluating and optimizing their interfirm relationship structures.

scholarly journals Effect of non-metallic inclusions on fatigue life of high-speed railway bearings

2020 ◽  
Vol 892 ◽  
pp. 012037
Author(s):  
Can Yang Ma ◽  
Gang Zhang ◽  
Yong Wu Wang ◽  
Zhen Qiang Zhang ◽  
Zhong Ming Ren
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
High Speed Railway ◽  
Metallic Inclusions

scholarly journals Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ding Youliang ◽  
Wang Gaoxin
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
High Speed ◽  
Field Monitoring ◽  
Generalized Extreme Value Distribution ◽  
Monitoring Data ◽  
Load Factor ◽  
High Speed Railway ◽  
Arch Bridge ◽  
The Impact

Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF) to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

scholarly journals Evolution of Rheological Behaviors of Styrene-Butadiene-Styrene/Crumb Rubber Composite Modified Bitumen after Different Long-Term Aging Processes

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2345 ◽  
Author(s):  
Yangsheng Ye ◽  
Gang Xu ◽  
Liangwei Lou ◽  
Xianhua Chen ◽  
Degou Cai ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Crumb Rubber ◽  
Modified Bitumen ◽  
High Speed Railway ◽  
Modified Asphalt ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

In this study, a new type of composite modified bitumen was developed by blending styrene-butadiene-styrene (SBS) and crumb rubber (CR) with a chemical method to satisfy the durability requirements of waterproofing material in the waterproofing layer of high-speed railway subgrade. A pressure-aging-vessel test for 20, 40 and 80 h were conducted to obtain bitumen samples in different long-term aging conditions. Multiple stress creep recovery (MSCR) tests, linear amplitude scanning tests and bending beam rheometer tests were conducted on three kinds of asphalt binders (SBS modified asphalt, CR modified asphalt and SBS/CR composite modified asphalt) after different long-term aging processes, including high temperature permanent deformation performance, resistance to low temperature thermal and fatigue crack. Meanwhile, aging sensitivities were compared by different rheological indices. Results showed that SBS/CR composite modified asphalt possessed the best properties before and after aging. The elastic property of CR in SBS/CR composite modified asphalt improved the ability to resist low temperature thermal and fatigue cracks at a range of low and middle temperatures. Simultaneously, the copolymer network of SBS and CR significantly improved the elastic response of the asphalt SBS/CR modified asphalt at a range of high temperatures. Furthermore, all test results indicated that the SBS/CR modified asphalt possesses the outstanding ability to anti-aging. SBS/CR is an ideal kind of asphalt to satisfy the demand of 60 years of service life in the subgrade of high speed railway.

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