The fatigue behavior and fatigue reliability analysis of vibroseis baseplates based on fracture mechanics

Author(s):  
Zhen Chen ◽  
Zhiqiang Huang ◽  
Shuang Jing ◽  
Zhifei Tao ◽  
Qi Zhao
Author(s):  
A. Ku ◽  
C. Serratella ◽  
R. Spong ◽  
R. Basu ◽  
G. Wang ◽  
...  

This paper outlines the essential steps taken in performing structural reliability calculations during the process of laying out a risk-based inspection program. The structural reliability analysis described in this paper essentially takes the deterministic finite element method (FEM) stress/fatigue analysis results, coupled with uncertain degradation mechanisms (e.g. corrosion rate, crack propagating parameters, etc.), and tracks the time-varying structural reliability index of the structural components under consideration. This can then be used to determine the timing for inspection of structural components. For the assessment of structural strength, an efficient and straightforward method is proposed to calculate the time-variant reliability index. This method is verified by an example problem and compared to the random process first-passage reliability solutions. Load combination issue is briefly discussed, in which an approach stems from the ABS Dynamic Loading Approach (DLA) coupled with concepts from Turkstra’s rule. This proposed simplistic load combination approach is verified through an example problem in which the result is compared to the solution calculated from a more sophisticated approach. Establishment of target reliability levels is also briefly discussed. For the assessment of fatigue behavior for welded connections, both S-N curve based and fracture mechanics based reliability methods are discussed. Their usefulness will be discussed in terms of both inspection interval as well as selecting the proper sampling percentage of connections to inspect. Statistical correlation among a group of similar connections is discussed to assist the selection of appropriate locations in the population of the aforementioned sampling. The usefulness of fatigue reliability analysis is also demonstrated by an example problem.


2008 ◽  
Vol 44-46 ◽  
pp. 1-14 ◽  
Author(s):  
Zhi Yun Shen ◽  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Wei Hua Zhang

Main progresses are reviewed and prospected from four elements on the fatigue reliability analysis research of China railway vehicles during recent decade. First, material fatigue database has been moderately developed and an emphasis was placed on the systemized fatigue properties. Second, a great of on-line inspections have been performed on the wheel-track contact forces and service stresses of key structures. A reliable vehicle dynamics simulation technique has been developed for simulating the contact forces and a multi-variable quadratic regression approach has been proposed to calculate the service stresses for recuing imperfect inspections. Third, systemized fatigue reliability researches have been made on improved fatigue limit measurement, probabilistic S-N curves, scale-deduced fatigue behavior, design Goodman-Smith diagram, and reliability analysis approach to address on the real super-long life of railway vehicle’s structures. Fourth, a critical safety state theory is established to address the time-dependent off-round wheel wear and the interactive fatigue damage between components. Fatigue cracking threshold measurement is improved. And a fatigue crack growth modeling is developed to cover entire physical process from the threshold to the fracture. The axle critical safety sizes are determined under considering the off-round wheel and the wheel critical safety wear sizes are measured to ensure the axle expected safety life. All researches are valuable to be further studied.


2012 ◽  
Vol 204-208 ◽  
pp. 3128-3131
Author(s):  
Li Rong Sha ◽  
Yue Yang

The ANN-based optimization for considering fatigue reliability requirements in structural optimization was proposed. The ANN-based response surface method was employed for performing fatigue reliability analysis. The fatigue reliability requirements were considered as constraints while the weight as the objective function, the ANN model was adopted to establish the relationship between the fatigue reliability and geometry dimension of the structure, the optimal results of the structure with a minimum weight was reached.


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