A Mixed-Effect Multi-Failure-Mechanism Fatigue Reliability Model

2010 ◽  
Vol 118-120 ◽  
pp. 37-42
Author(s):  
Li Yang Xie ◽  
Wen Qiang Lin ◽  
Feng Lu
Keyword(s):  
Distribution Function ◽  
Probability Function ◽  
Failure Mechanisms ◽  
Reliability Model ◽  
Conditional Survival ◽  
Cycle Fatigue ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Mixed Effect ◽  
Reliability Models

Based on the concept of multilevel statistics, mixed-effect fatigue reliability models are presented, by which fatigue reliability can be directly calculated according to stress distribution and fatigue life distribution function condition to stress. Mathematically, the fatigue reliability is estimated as the expectation of a conditional survival probability function to the stochastic stress history. Especially, such models are capable of estimating the fatigue reliability of a component with competing failure mechanisms such as conventional fatigue and giga-cycle fatigue, where two groups of P-S-N curves are involved.

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.

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).

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.

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.

High Cycle Fatigue Resistance and Reliability Assessment of Flexible Printed Circuitry

2002 ◽  
Vol 124 (3) ◽  
pp. 254-259 ◽  
Author(s):  
Elena Martynenko ◽  
Wen Zhou ◽  
Alexander Chudnovsky ◽  
Ron S. Li ◽  
Larry Poglitsch
Keyword(s):  
Fatigue Resistance ◽  
High Cycle Fatigue ◽  
Failure Mechanisms ◽  
Three Dimensional ◽  
Reliability Assessment ◽  
Core Layer ◽  
High Strength ◽  
Multiple Cracks ◽  
Material System ◽  
Cycle Fatigue

Flexible printed circuitry (FPC) is a patterned array of conductors supported by a flexible dielectric film made of high strength polymer material such as polyimide. The flexibility of FPC provides an opportunity for three dimensional packaging, easy interconnections and dynamic applications. The polymeric core layer is the primary load bearing structure when the substrate is not supported by a rigid plate. In its composite structure, the conductive layers are more vulnerable to failure due to their lower flexibility compared to the core layer. Fatigue data on FPCs are not commonly available in published literature. Presented in this paper is the fatigue resistance and reliability assessment of polyimide based FPCs. Fatigue resistance of a specific material system was analyzed as a function of temperature and frequency through experiments that utilized a specially designed experimental setup consisting of sine servo controller, electrodynamic shaker, continuity monitor and temperature chamber. The fatigue characteristics of the selected material system are summarized in the form of S-N diagrams. Significant decrease in fatigue lifetime has been observed due to higher displacements in high cycle fatigue. Observed temperature effect was however counter-intuitive. Failure mechanisms are discussed and complete fracture analysis is presented. In various FPC systems, it has been found that the changes take place in FPC failure mechanisms from well-developed and aligned single cracks through the width at low temperature to an array of multiple cracks with random sizes and locations at high temperature.

scholarly journals Characteristics and Application of the NHPP Log-Logistic Reliability Model

2018 ◽  
Vol 8 (1) ◽  
pp. 44
Author(s):  
Lutfiah Ismail Al turk
Keyword(s):  
Evaluation Criteria ◽  
Real Data ◽  
Least Square ◽  
Estimation Methods ◽  
Data Sets ◽  
Reliability Model ◽  
Reliability Engineering ◽  
Reliability Models ◽  
Time Domain Data ◽  
Linear Least Square

In this paper, a Nonhomogeneous Poisson Process (NHPP) reliability model based on the two-parameter Log-Logistic (LL) distribution is considered. The essential model’s characteristics are derived and represented graphically. The parameters of the model are estimated by the Maximum Likelihood (ML) and Non-linear Least Square (NLS) estimation methods for the case of time domain data. An application to show the flexibility of the considered model are conducted based on five real data sets and using three evaluation criteria. We hope this model will help as an alternative model to other useful reliability models for describing real data in reliability engineering area.

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