Estimation of Cumulative Fatigue Damage Under Random Loading

1976 ◽  
Vol 98 (1) ◽  
pp. 348-353 ◽  
Author(s):  
A. K. Abu-Akeel
Keyword(s):  
Fatigue Damage ◽  
Computation Time ◽  
Straight Line Segment ◽  
Computer Applications ◽  
Accurate Estimation ◽  
Random Loading ◽  
Structural Element ◽  
Load Curve ◽  
Straight Line ◽  
Cumulative Fatigue Damage

A method is presented that leads to accurate estimation of the cumulative fatigue damage incurred in a randomly loaded structural element when loading is given in the form of spectral density load, or stress, plots. The load plots are here approximated by a series of straight lines and a closed formula is obtained to yield the damage incurred by the load within each straight line segment. The method avoids the errors that result from human misjudgment in the commonly used curve-stepping approach. It is also adaptable for computer applications and can be incorporated in a stress calculation program to save on computation time. In comparison to curve stepping, five straight-line segments may give the same accuracy as a hundred curve steps. This contrast, however, depends on the degree of irregularity of the load curve.

A method for estimating rainflow fatigue damage of narrowband non-Gaussian random loadings

2014 ◽  
Vol 228 (14) ◽  
pp. 2459-2468 ◽  
Author(s):  
HW Cheng ◽  
JY Tao ◽  
X Chen ◽  
Y Jiang
Keyword(s):  
Fatigue Damage ◽  
Fourth Order ◽  
Analytical Solutions ◽  
Estimation Methods ◽  
Accurate Estimation ◽  
Damage Estimation ◽  
Random Loading ◽  
New Approach ◽  
Computational Errors ◽  
Non Gaussian

We describe efforts to improve the accuracy of fatigue damage estimation methods of narrowband non-Gaussian random loading. The available analytical solutions are reviewed and briefly summarized, and the reasons for the occurrence of computational errors during nonlinear transformation-based methods are determined. The computational errors are mainly due to inconsistencies in the statistical moments above fourth order. A new approach is proposed for the evaluation of rainflow fatigue damage. This approach avoids the problem of transformation-based methods and provides accurate estimation for fatigue damage of narrowband leptokurtic non-Gaussian random loading. Additionally, the applicability of the proposed method to Gaussian random loading is investigated. Finally, two examples are carried out and comparisons are made to more commonly used methods to demonstrate the capabilities and brevity of the proposed algorithm.

Cumulative Fatigue Damage With Random Loading

1962 ◽  
Vol 84 (3) ◽  
pp. 403-408 ◽  
Author(s):  
R. R. Gatts
Keyword(s):  
Fatigue Damage ◽  
Stress Amplitude ◽  
Amplitude Distribution ◽  
General Concept ◽  
Time Function ◽  
Discrete Distributions ◽  
Random Loading ◽  
Linear Rule ◽  
Cumulative Fatigue Damage ◽  
Distribution Of Stress

A general concept of the accumulation of fatigue damage is applied where stress amplitude is a random time function with a specified amplitude distribution. A differential equation relating damage accumulation to the amplitude distribution of stress is derived. This equation is applicable to both continuous and discrete distributions. Solutions of the equation are used to predict life under random loading on the basis of constant amplitude S-N data. Such predictions are compared for both continuous and discrete stress amplitude distributions and found in better over-all agreement with the data than comparable predictions by the linear rule.

Cumulative Fatigue Damage Under Stress-Controlled Conditions

1971 ◽  
Vol 93 (4) ◽  
pp. 691-698 ◽  
Author(s):  
Thang Bui Quoc ◽  
J. Dubuc ◽  
A. Bazergui ◽  
A. Biron
Keyword(s):  
Theoretical Analysis ◽  
Fatigue Damage ◽  
Experimental Results ◽  
Published Data ◽  
Mean Stress ◽  
Remaining Life ◽  
Random Loading ◽  
Controlled Conditions ◽  
Cumulative Fatigue Damage ◽  
Good Agreement

A theoretical analysis of uniaxial cumulative fatigue damage is presented together with a large number of experimental results on unnotched specimens of A-201 and A-517 steels. The theory developed permits the prediction of fatigue curves for stress-controlled conditions with zero or positive mean stress as well as the evaluation of the damage accumulated during a fatigue test and hence the prediction of the remaining life of a specimen. Theory is in good agreement with the experimental results as well as with published data on other materials. The development may be extended to other types of tests such as strain-controlled or random loading conditions.

Nonlinear Fatigue Damage Accumulation Under Random Loading

1996 ◽  
Vol 118 (2) ◽  
pp. 168-173 ◽  
Author(s):  
W. Q. Zhu ◽  
M. X. Jiang
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Stochastic Theory ◽  
Reliability Function ◽  
Random Loading ◽  
Fatigue Damage Accumulation ◽  
Probability Densities ◽  
Cumulative Fatigue Damage ◽  
Analytical Expressions ◽  
Damage Rule

The analytical expressions for the probability densities of the cumulative fatigue damage and fatigue life and for the reliability function are obtained for a mechanical or structural component subject to stationary random stress process on the basis of a stochastic theory of fatigue damage accumulation proposed by the first author and his co-worker and the Morrow’s nonlinear damage rule. The comparison between the results from Morrow’s and Palmgren-Miner’s damage rules for the case when the stress is a narrow-band stationary Gaussian process with zero mean is made and some important conclusions are drawn.

scholarly journals Impact of train-induced vibration on railway cable-stayed bridges fatigue evaluation

2016 ◽  
Vol 11 (2) ◽  
pp. 102-110 ◽  
Author(s):  
Shiling Pei ◽  
Yongle Li ◽  
Yulong Bao ◽  
Xin Li ◽  
Shizhong Qiang
Keyword(s):  
Fatigue Damage ◽  
Welded Joints ◽  
Moving Load ◽  
Numerical Procedure ◽  
Coupled System ◽  
Accurate Estimation ◽  
Truss Bridges ◽  
Cumulative Fatigue Damage ◽  
Fatigue Evaluation ◽  
Critical Locations

Under repetitive heavy train traffic, railway steel truss bridges tend to have many fatigue related performance issues, especially at welded joints. Accurate estimation of the stress history at critical locations of welded joints under vehicle loading is important for joint fatigue design. Traditionally, vehicle loads were treated as moving static loads without considering their dynamic effects. In this study, a numerical procedure was introduced to incorporate the effect of dynamic response of the train–bridge coupled system on nodal fatigue damage. The proposed approach employs a twolevel modelling scheme which combines dynamic analysis for the full train-bridge system and detailed stress analysis at the joint. Miner rule was used to determine the cumulative fatigue damage at critical locations on the welded joint. A sensitivity analysis was conducted for different train loading configurations. It was determined that dynamic vibration negatively influences fatigue life. The calculated cumulative damage at investigated locations can more than the damage estimated using only static moving load method.

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