scholarly journals Numerical Investigation on Crack Propagation and Fatigue Life Estimation of Shield Lining under Train Vibration Load

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Long-gang Tian ◽  
Zi-ling Cheng ◽  
Zhi-qiang Hu
Keyword(s):  
Fatigue Life ◽  
Crack Propagation ◽  
Tunnel Lining ◽  
Shield Tunnel ◽  
Vibration Load ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Lining Structure ◽  
Train Speed ◽  
Train Vibration

Dynamic loads such as the train vibration load usually act on the shield tunnel lining in the long term, which could make the initial flaws in shield segment propagate and gradually weaken the robustness of the tunnel structure. In this paper, a three-dimensional numerical model of shield tunnel lining structure with the initial defect is built to study its dynamic reaction and fatigue crack propagation under the train vibration load. Furthermore, the damage to intact shield segment caused by train vibration load is studied by employing the rain-flow counting method and the Miner damage theory, and a rational fatigue life estimation for the concrete shield tunnel lining is finally made. Results show that crack propagation is influenced by both the train speed and train axle, the higher the train speed, the longer the final crack, and train axle has a larger influence than train speed on the crack propagation in shield tunnel segment. The shield tunnel lining structure of Nanjing Metro Line 5 can meet the demand of working for a hundred years under the current working conditions.

Load Spectrum Compiling and Fatigue Life Estimation of the Automobile Wheel Hub

2020 ◽  
Vol 13 ◽  
Author(s):  
Xintian Liu ◽  
Yang Qu ◽  
Xiaobing Yang ◽  
Yongfeng Shen
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Two Dimensional ◽  
Load Spectrum ◽  
One Dimensional ◽  
Life Estimation ◽  
Load Spectra ◽  
Fatigue Life Estimation ◽  
Program Load Spectrum ◽  
Program Load

Background:: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective:: This paper introduces a method to study the fatigue life of car hub based on the road load collected from test site. Methods:: Based on interval analysis, the distribution characteristics of load spectrum are analyzed. The fatigue life estimation of one - dimensional and two - dimensional load spectra is compared by compiling load spectra. Results:: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397,100 km to 529,700 km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimates the fatigue life of wheel hub of the interval is 329900 km to 435200 km, than one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion:: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of auto parts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.

Notch fatigue life estimation of Ti-6Al-4V

2021 ◽  
Vol 120 ◽  
pp. 105098
Author(s):  
Camilla Ronchei ◽  
Sabrina Vantadori
Keyword(s):  
Fatigue Life ◽  
Life Estimation ◽  
Fatigue Life Estimation

An Investigation of Cyclic Transient Behavior and Implications on Fatigue Life Estimates

1997 ◽  
Vol 119 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Yanyao Jiang ◽  
Peter Kurath
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Cyclic Hardening ◽  
Transient Behavior ◽  
Fatigue Tests ◽  
304 Stainless Steel ◽  
Deformation History ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Track Deformation

Current research focuses on proportional cyclic hardening and non-Massing behaviors. The interaction of these two hardenings can result in the traditionally observed overall softening, hardening or mixed behavior exhibited for fully reversed strain controlled fatigue tests. Proportional experiments were conducted with five materials, 304 stainless steel, normalized 1070 and 1045 steels, and 7075-T6 and 6061-T6 aluminum alloys. All the materials display similar trends, but the 304 stainless steel shows the most pronounced transient behavior and will be discussed in detail. Existing algorithms for this behavior are evaluated in light of the recent experiments, and refinements to the Armstrong-Frederick class of incremental plasticity models are proposed. Modifications implemented are more extensive than the traditional variation of yield stress, and a traditional strain based memory surface is utilized to track deformation history. Implications of the deformation characteristics with regard to fatigue life estimation, especially variable amplitude loading, will be examined. The high-low step loading is utilized to illustrate the effect of transient deformation on fatigue life estimation procedures, and their relationship to the observed and modeled deformation.

Fatigue Life Estimation of a Notched Shaft based on Combined Deviatoric Strain Amplitudes

2014 ◽  
Author(s):  
Luiz Henrique Bresser Cardoso de Mello ◽  
Fábio Comes de Castro
Keyword(s):  
Fatigue Life ◽  
Life Estimation ◽  
Fatigue Life Estimation

Numerical model for bending fatigue life estimation of carburized spur gears with consideration of the adjacent tooth effect

2021 ◽  
Vol 153 ◽  
pp. 106515
Author(s):  
Krešimir Vučković ◽  
Ivan Čular ◽  
Robert Mašović ◽  
Ivica Galić ◽  
Dragan Žeželj
Keyword(s):  
Fatigue Life ◽  
Numerical Model ◽  
Spur Gears ◽  
Bending Fatigue ◽  
Life Estimation ◽  
Adjacent Tooth ◽  
Fatigue Life Estimation
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