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.

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.

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.

A Procedure for Fast Evaluation of High-Cycle Fatigue Under Multiaxial Random Loading

2001 ◽  
Author(s):  
Bin Li ◽  
Manuel de Freitas
Keyword(s):  
Shear Stress ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Hydrostatic Stress ◽  
Evaluation Procedure ◽  
Cycle Fatigue ◽  
Random Loading ◽  
Proportional Loading ◽  
Fast Evaluation

Abstract This paper presents a fast evaluation procedure for high-cycle fatigue (HCF) under multiaxial random loading. The recent multiaxial cycle counting method of Wang and Brown is used to identify the loading reversals. For each identified reversal, the effective shear stress amplitude is directly calculated from the component stress ranges by an equation derived from the MCE approach, which is a newly developed method to account for non-proportional loading effect. This shear stress amplitude and the maximum hydrostatic stress during the time period of an identified reversal are used to evaluate the fatigue damage for that reversal by Crossland’s criterion. The fatigue damage of the loading block is then calculated by summing the damages of all the identified reversals by Miner’s rule. Comparisons with other multiaxial HCF approaches show that the procedure is a computationally efficient and conservative engineering approach.

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.

Study on Wave Load Prediction and Fatigue Damage Analysis of River-Sea-Going Ship

2018 ◽  
Author(s):  
Guohu Guo ◽  
Yiwen Wang ◽  
Jin Gan ◽  
Weiguo Wu ◽  
Yunling Ye
Keyword(s):  
Finite Element ◽  
Stress Response ◽  
Fatigue Damage ◽  
Response Spectrum ◽  
Container Ship ◽  
Stress Range ◽  
Wave Load ◽  
Fatigue Assessment ◽  
Cumulative Fatigue Damage ◽  
Distribution Of Stress

With the consideration of shipping efficiency and the limited conditions of the Yangtze River, flat and wide ship become the preferred type for River-Sea-Going ship. This kind of structure is adverse to the ship’s stiffness under longitudinal bending, transverse bending. And two-stage repeated loading brings to the fatigue assessment of the ship structure new uncertainties, so accurate cumulative fatigue damage is a matter of necessary. Based on the theory of three-dimensional potential flow, the hydrodynamic analysis of River-Sea-Going container ship under specific route is carried out. The hull motion and the load transfer function of each section are obtained. The finite element model is used to calculate the amplitude-frequency response Operator RAOs. The influence of special routes and speed factors are also considered. Based on the frequency domain spectral analysis method combined with the scatter diagram of E1 sea area, the characteristics of wave-induced load are analyzed under 10−7.5 probability level. The stress response spectrum and the short-term distribution of stress range are obtained by combining the structural stress response calculation with the whole ship finite element structure model. The long-term distribution of stress response spectrum and stress range is also obtained. The cumulative fatigue damage of River-Sea-Going container ship under the special route is evaluated by using the S-N curve recommended by the criterion. It can provide the basis for the fatigue assessment of the new type of River-Sea-Going container ship.

A Procedure for Fast Evaluation of High-Cycle Fatigue Under Multiaxial Random Loading

2002 ◽  
Vol 124 (3) ◽  
pp. 558-563 ◽  
Author(s):  
Bin Li ◽  
Manuel de Freitas
Keyword(s):  
Shear Stress ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Hydrostatic Stress ◽  
Evaluation Procedure ◽  
Cycle Fatigue ◽  
Computationally Efficient ◽  
Random Loading ◽  
Fast Evaluation

This paper presents a fast evaluation procedure for high-cycle fatigue (HCF) under multiaxial random loading. The recent multiaxial cycle counting method of Wang and Brown is used to identify the loading reversals. For each identified reversal, the effective shear stress amplitude is directly calculated from the component stress ranges by an equation derived from the MCE approach, which is a newly developed method to account for nonproportional loading effect. This shear stress amplitude and the maximum hydrostatic stress during the time period of an identified reversal are used to evaluate the fatigue damage for that reversal by Crossland’s criterion. The fatigue damage of the loading block is then calculated by summing the damages of all the identified reversals by Miner’s rule. Comparisons with other multiaxial HCF approaches show that the procedure is a computationally efficient and conservative engineering approach.

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