Fatigue Reliability Functions in Semilogarithmic Coordinates

1991 ◽  
Author(s):  
Vladimir A. Avakov
Keyword(s):  
Fatigue Life ◽  
Coordinate System ◽  
Strength Distribution ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Similar Transformation ◽  
Asymptotic Type ◽  
Life Distributions ◽  
Strength Distributions

Abstract In the previous publication [2], the transformation between fatigue life and strength distribution was established using double-logarithmic coordinate system (lnN-lnS). Here, a similar transformation is established using a semi logarithmic (lnN-S) coordinate system. With the aid of the developed orthogonal relations, lognormal, Weibull and three-parameter logweibull life distributions have been transformed into normal, asymptotic type 1 of smallest value, and three-parameter Weibull strength distributions, respectively. This procedure may be applied to other types of fatigue life distribution.

Fatigue Reliability Functions in Semilogarithmic Coordinates

1991 ◽  
Vol 113 (3) ◽  
pp. 352-358 ◽  
Author(s):  
V. A. Avakov
Keyword(s):  
Fatigue Life ◽  
Coordinate System ◽  
Strength Distribution ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Similar Transformation ◽  
Asymptotic Type ◽  
Life Distributions ◽  
Straight Lines

In the previous publication [2], the transformation between fatigue life and strength distribution was established using double-logarithmic coordinate system (InN-InS). Here, a similar transformation is established using a semilogarithmic (InN-S) coordinate system. It is assumed that the set of S = Sj (N/Qj) (j = 1,2,...,p) relations, plotted in the InN-S coordinates, becomes a family of parallel straight lines. With the aid of the developed orthogonal relations, lognormal, Weibull and three-parameter logweibull life distributions have been transformed into normal, asymptotic type 1 of smallest value, and three-parameter Weibull strength distributions, respectively. This procedure may be applied to other types of fatigue life distribution.

Fatigue Reliability Functions

1989 ◽  
Vol 111 (4) ◽  
pp. 443-455 ◽  
Author(s):  
V. A. Avakov ◽  
R. G. Shomperlen
Keyword(s):  
Distribution Function ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Curve ◽  
Strength Distribution ◽  
Distribution Model ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Statistical Procedures ◽  
Two Parameter

There are many fatigue test and statistical procedures to establish the life distribution function Q = Q(N) at constant stress (S) level. But the stress distribution function, Q = Q(S), at specified life (N) is more important to the designer, and it remains less developed. Generally, if the fatigue life distribution Q(N) and fatigue curve S(N) equations are defined, the fatigue strength distribution Q(S) is implied. However, it has been shown [4, 6, 7, 9] that any life distribution model Q(N) may be transformed into the complicated strength distribution function Q(S). In this study orthogonal relations have been developed in order to predict complications and to resolve the problem under certain conditions. With the aid of the orthogonal relations strength distributions Q(S) have been deduced using (1) lognormal, (2) two-parameter Weibull, and (3) three-parameter logweibull life models Q(N).

A Simulation Method of Establishing Fatigue Life Distribution

1976 ◽  
Vol 98 (1) ◽  
pp. 183-188 ◽  
Author(s):  
H. A. Elmaraghy ◽  
J. N. Siddall
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Digital Simulation ◽  
Simulation Method ◽  
Fatigue Tests ◽  
Design Tool ◽  
Statistical Characteristics ◽  
Life Distribution ◽  
Parametric Studies ◽  
Life Distributions

This paper presents a Monte Carlo simulation method for fatigue failure, by which the randomness of two material properties as well as that of the applied load can be incorporated into a stochastic model using an appropriate failure criterion to predict the statistical characteristics of fatigue life under constant and random amplitude cyclic loading conditions. In this technique, both the endurance limit Se and the fatigue strength coefficient Sf′ are treated as stochastic variables. The combined effect of the randomness of Se, Sf′, and the applied stress on the statistical characteristics of fatigue lives is predicted analytically using digital simulation of fatique tests. The life distributions and their statistical characteristics are found to be in good agreement with those obtained from analyzing the experimental results, indicating that the proposed technique and the underlying assumptions and hypotheses are adequate. The suggested method is believed to be an effective, fast, and easy-to-use design tool which is suitable for use on electronic computers. It is ideal for parametric studies compared with the costly and time-consuming laboratory fatigue tests. Minimum experimental data are needed as a basis for the analysis. New results are presented which show the effect of the randomness of the loads and material properties on the randomness of fatigue life distribution.

Damage Equivalent Method of Fatigue Reliability Analysis of Load-Sharing Parallel System

2008 ◽  
Vol 44-46 ◽  
pp. 853-858 ◽  
Author(s):  
Guang Bo Hao ◽  
Li Yang Xie
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
Load Sharing ◽  
Parallel System ◽  
Reliability Model ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Life Distributions ◽  
Equivalent Method ◽  
Full Probability

As for load-sharing parallel system like multi-engine system and wire cable, dependence-failure must occur due to load redistributing, so the component life distributions changed. After the analysis of the disadvantage of failure probability equivalent principle and the transformation of equivalent working time of different life distribution based on damage equivalent principle, the parallel system reliability model applying full probability formula is established. The established reliability model provides a new method for reliability analysis of load-sharing parallel system whose component life follows any distribution.

Study on the Fatigue Reliability Model Based on Probability Distribution of Fatigue Life under Spectrum Loading

2010 ◽  
Vol 44-47 ◽  
pp. 2788-2792
Author(s):  
Ying Wu ◽  
Li Yang Xie
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Probability Distribution ◽  
Life Cycles ◽  
Reliability Model ◽  
Fatigue Reliability ◽  
Load History ◽  
Life Distribution ◽  
Variable Amplitude ◽  
Variable Amplitude Load

Under variable amplitude load history the exact distribution of fatigue strength corresponding to a specified number of life cycles cannot be obtained exactly by test, fatigue strength distribution can be obtained from fatigue life distribution. According to statistical property analysis of Miner cumulative damage rule, probability distribution of fatigue life under variable amplitude load history is predicted based-on constant amplitude median Sa-Sm-N surface. In the end, a fatigue reliability model is established to calculate fatigue reliability according to stress distribution as well as fatigue life distribution function. The model is applicable to calculate fatigue reliability under stochastic load environments.

Minimal distributions in a stochastic partial ordering and bounds for Gaussian processes

1983 ◽  
Vol 20 (03) ◽  
pp. 529-536
Author(s):  
W. J. R. Eplett
Keyword(s):  
Gaussian Process ◽  
Gaussian Processes ◽  
Partial Ordering ◽  
Boundary Crossing ◽  
Conditional Probabilities ◽  
Life Distribution ◽  
Life Distributions ◽  
Bounded Below ◽  
Crossing Probabilities

A natural requirement to impose upon the life distribution of a component is that after inspection at some randomly chosen time to check whether it is still functioning, its life distribution from the time of checking should be bounded below by some specified distribution which may be defined by external considerations. Furthermore, the life distribution should ideally be minimal in the partial ordering obtained from the conditional probabilities. We prove that these specifications provide an apparently new characterization of the DFRA class of life distributions with a corresponding result for IFRA distributions. These results may be transferred, using Slepian's lemma, to obtain bounds for the boundary crossing probabilities of a stationary Gaussian process.

The Fatigue Reliability Evaluation & Improvement of the Single-Arm Subway Current Collector

2012 ◽  
Vol 215-216 ◽  
pp. 826-831 ◽  
Author(s):  
Yu Chen ◽  
Zhi Ming Liu ◽  
Qiang Li
Keyword(s):  
Fatigue Life ◽  
Calculation Result ◽  
Dynamic Stress ◽  
Current Collector ◽  
Reliability Evaluation ◽  
Fatigue Reliability ◽  
Railway Vehicles ◽  
Load Spectra ◽  
Reliability Method

This study developed a fatigue reliability method for evaluating and improving the key parts on railway vehicles, which was applied to real structures. The study involved a type of single-arm current collector, while its contact shoe often collapsed in operation and needs improvements. The dynamic stress data from the actual line was tested and converted to load spectra based on damage consistency rule, and then the fatigue life of the contact shoe structure was achieved. The calculation result comes to correspond to its operation life. Based on the method, an improving plan for the structure was developed under optimizing algorithms.

Prediction of the Strength of Ceramic Tubular Components: Part II — Experimental Verification

1991 ◽  
Author(s):  
D. L. Shelleman ◽  
O. M. Jadaan ◽  
J. C. Conway ◽  
J. J. Mecholsky
Keyword(s):  
Silicon Carbide ◽  
Statistical Theory ◽  
Room Temperature ◽  
Strength Distribution ◽  
Ring Test ◽  
Stress Distributions ◽  
Pressure Test ◽  
Tubular Components ◽  
Tubular Specimens ◽  
Strength Distributions

Abstract The strength distribution of reaction bonded silicon carbide tubes that failed by internal pressurization was predicted from strength distributions obtained from simple laboratory test specimens at room temperature. The strength distributions of flexure bars, C-rings tested in tension, C-rings tested in compression, diametrally compressed O-rings, and internally pressurized short tubes were compared to the strength distribution of internally pressurized long tubes. The methodology involved application of Weibull statistical theory using elasticity theory to define the stress distributions in the simple specimens. The flexural specimens did not yield acceptable results, since they were ground prior to testing, thereby altering their flaw population in comparison with the processing induced flaw populations of the tubular specimens. However, the short tube internal pressure test, the c-ring tested in tension and the diametrally compressed o-ring test configurations yielded accurate predictions, since these specimens more accurately represent the strength limiting flaw population in the long tubes.

Sign in / Sign up

Export Citation Format

Share Document