The Statistics Analysis of Degradation Data Based on the Degradation Amount Distribution

2013 ◽  
Vol 791-793 ◽  
pp. 1260-1263
Author(s):  
Yi Zhou He ◽  
Jin Huang Wu ◽  
Yi Dong Wang ◽  
Wei Hua Liu
Keyword(s):  
High Reliability ◽  
Performance Degradation ◽  
Accelerated Life Test ◽  
Test Reliability ◽  
Analysis Method ◽  
Life Test ◽  
Failure Data ◽  
Degradation Data ◽  
Accelerated Life ◽  
Long Life

In order to solve the key technology and method in reliability study of the long-life products, the analysis method of degradation data based on the degradation amount distribution was proposed in this paper. On the basis of statistical model, by analyzing three models of degradation amount distribution, it can be got there is a large number of reliability information with high-reliable and long-life products in performance degradation data. In the case of not getting the failure data by life test and accelerated life test, reliability assessment and life prediction could be carried out for high reliability and long life products with performance degradation data.

The Statistics Analysis of Degradation Data Based on the Degradation Amount Distribution

2013 ◽  
Vol 739 ◽  
pp. 781-784
Author(s):  
Jun Sheng Wang ◽  
Yi Zhou He ◽  
Jin Huang Wu ◽  
Jun Wei Lei
Keyword(s):  
High Reliability ◽  
Performance Degradation ◽  
Accelerated Life Test ◽  
Test Reliability ◽  
Analysis Method ◽  
Life Test ◽  
Failure Data ◽  
Degradation Data ◽  
Accelerated Life ◽  
Long Life

In order to solve the key technology and method in reliability study of the long-life products, the analysis method of degradation data based on the degradation amount distribution was proposed in this paper. On the basis of statistical model, by analyzing three models of degradation amount distribution, it can be got there is a large number of reliability information with high-reliable and long-life products in performance degradation data. In the case of not getting the failure data by life test and accelerated life test, reliability assessment and life prediction could be carried out for high reliability and long life products with performance degradation data.

An accelerated life test plan for a two-component parallel system under ramp-stress loading using masked data

2018 ◽  
Vol 35 (3) ◽  
pp. 811-820 ◽  
Author(s):  
Preeti Wanti Srivastava ◽  
Savita Savita
Keyword(s):  
Optimality Criterion ◽  
High Reliability ◽  
Parallel System ◽  
Stress Rate ◽  
Accelerated Life Test ◽  
Cumulative Exposure ◽  
Life Test ◽  
Optimal Plan ◽  
Content Type ◽  
Accelerated Life

Purpose Most of the literature on the design of accelerated life test (ALT) plan focus on a single system (subsystem) totally disregarding its internal configuration. Many a times it is not possible to identify the components that cause the system failure or that the cause can only be identified by a subset of its components resulting in a masked observation. The purpose of this paper is to deal with the planning of ramp-stress accelerated life testing for a high-reliability parallel system comprising two dependent components using masked failure data. Such a testing may prove to be useful in a twin-engine aircraft. A ramp-stress results when stress applied on the system increases linearly with time. Design/methodology/approach A parallel system with two dependent components is taken with dependency modeled by Gumbel-Hougaard copula. The stress-life relationship is modeled using inverse power law, and cumulative exposure model is assumed to model the effect of changing stress. The method of maximum likelihood is used for estimating design parameters. The optimal plan consists in finding optimal stress rate using D-optimality criterion. Findings The optimal plan consists in finding optimal stress rate using D-optimality criterion by minimizing the reciprocal of the determinant of Fisher information matrix. The proposed plan has been explained using a numerical example and carrying out a sensitivity analysis. Originality/value The model formulated can help reliability engineers obtain reliability estimates quickly of high-reliability products that are likely to last for several years.

Optimum modified ramp-stress ALT plan with competing causes of failure

2017 ◽  
Vol 34 (5) ◽  
pp. 733-746 ◽  
Author(s):  
Preeti Wanti Srivastava ◽  
Tanu Gupta
Keyword(s):  
Change Point ◽  
Fisher Information Matrix ◽  
High Reliability ◽  
Information Matrix ◽  
Stress Rate ◽  
Accelerated Life Test ◽  
Life Test ◽  
Optimal Plan ◽  
Content Type ◽  
Accelerated Life

Purpose Accelerated life test is undertaken to induce early failure in high-reliability products likely to last for several years. Most of these products are exposed to several fatal risk factors and fail due to one of them. Examples include solar lighting device with two failure modes: capacitor failure, and controller failure. It is necessary to assess each risk factor in the presence of other risk factors as each one cannot be studied in isolation. The purpose of this paper is to explore formulation of optimum time-censored accelerated life test model under modified ramp-stress loading when different failure causes have independent exponential life distributions. Design/methodology/approach The modified ramp-stress uses one test chamber in place of the various chambers used in the normal ramp-stress accelerate life test thus saving experimental cost. The stress-life relationship is modeled by inverse power law, and for each failure cause, a cumulative exposure model is assumed. The method of maximum likelihood is used for estimating design parameters. The optimal plan consists in finding out relevant experimental variables, namely, stress rate and stress rate change point(s). Findings The optimal plan is devised using D-optimality criterion which consists in finding out optimal stress rate and optimal stress rate change point by maximizing logarithm of determinant of Fisher information matrix to the base 10. This criterion is motivated by the fact that the volume of joint confidence region of model parameters is inversely proportional to square root of determinant of Fisher information matrix. The results of sensitivity analysis show that the plan is robust to small deviations from the true values of baseline parameters. Originality/value The model formulated can help reliability engineers obtain reliability estimates quickly of high-reliability products that are likely to last for several years.

scholarly journals Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Ma Xiaobing ◽  
Zhang Yongbo
Keyword(s):  
Carbon Fiber ◽  
Test Data ◽  
Life Prediction ◽  
Rupture Life ◽  
Accelerated Life Testing ◽  
Accelerated Life Test ◽  
Life Testing ◽  
Life Test ◽  
Failure Data ◽  
Accelerated Life

An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life test due to the time limitation. Therefore, most of the data presented to be high censored in high stress level and zero-failure data in low stress level. When using the traditional method for rupture life prediction, the results showed to be of lower confidence. In this study, the consistency of failure mechanism for carbon fiber and cylinder was analyzed firstly. According to the analysis result, the statistical test information of carbon fiber could be utilized for the accelerated model constitution. Then, rupture life prediction method for cylinder was proposed based on the accelerated life test data and carbon fiber test data. In this way, the life prediction accuracy of cylinder could be improved obviously, and the results showed that the accuracy of this method increased by 35%.

Analysis of Constant-Stress Accelerated-Life-Test Data of Electric Appliances

2011 ◽  
Vol 268-270 ◽  
pp. 51-55
Author(s):  
Jing Zhao ◽  
Li Hua Sun ◽  
Yong Chun Liang ◽  
Cai Hong Yan ◽  
Hui Wang
Keyword(s):  
Test Data ◽  
Shape Parameter ◽  
Model Fitting ◽  
Computer Software ◽  
Constant Stress ◽  
Accelerated Life Test ◽  
Analysis Method ◽  
Reliability Engineering ◽  
Life Test ◽  
Accelerated Life

In the field of electric appliances’ reliability, the constant-stress accelerated-life-test is commonly used to test the reliability of electric appliances. A new analysis method based on constructed data is introduced to analyze the constant-stress accelerated-life-test data of electric appliances under Weibull distribution. The correlation between shape parameter and characteristic life is took into account and the estimated value of characteristic life is modified, which increase the model fitting optimization and improve the analysis precision. Moreover, the method avoids table lookup and is easy to be realized by computer software in the application of reliability engineering for electric appliances.

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