Statistical Monitoring of Time-to-Failure Data Using Rank Tests

2011 ◽  
Vol 28 (3) ◽  
pp. 321-333 ◽  
Author(s):  
Zhiguo Li ◽  
Shiyu Zhou ◽  
Crispian Sievenpiper ◽  
Suresh Choubey
Keyword(s):  
Time To Failure ◽  
Rank Tests ◽  
Statistical Monitoring ◽  
Failure Data

Texture and Microstructure Effects on Electromigration Behavior of Aluminum Metallization

1991 ◽  
Vol 225 ◽  
Author(s):  
D. B. Knorr ◽  
K. P. Rodbell ◽  
D. P. Tracy
Keyword(s):  
Grain Size ◽  
Standard Deviation ◽  
Pure Aluminum ◽  
Time To Failure ◽  
X Ray Diffraction ◽  
Aluminum Films ◽  
Failure Data ◽  
Transmission Electron ◽  
Aluminum Metallization ◽  
Microstructure Effects

ABSTRACTPure aluminum films are deposited under a variety of conditions to vary the crystallographic texture. After patterning and annealing at 400°C for 1 hour, electromigration tests are performed at several temperatures. Failure data are compared on the basis of t50 and standard deviation. Microstructure is quantified by transmission electron microscopy for grain size and grain size distribution and by X-ray diffraction for texture. A strong (111) texture significantly improves the electromigration lifetime and decreases the standard deviation in time to failure. This improvement correlates with both the fraction and sharpness of the (111) texture component.

Analysis of HDPE Failure Data in Support of Development of Flaw Acceptance Criteria for Butt Fusion Joints

2020 ◽  
Author(s):  
Cheng Liu ◽  
Douglas Scarth ◽  
Douglas P. Munson ◽  
Ryan Wolfe
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Failure Time ◽  
Slow Crack Growth ◽  
Time To Failure ◽  
Acceptance Criteria ◽  
Failure Data ◽  
Criteria For Evaluation ◽  
Hdpe Pipes

Abstract There is a need for ASME B&PV Code procedures and acceptance criteria for evaluation of flaws detected by inspection of high density polyethylene (HDPE) piping items in safety Class 3 systems. To support the development of flaw acceptance criteria for butt fusion joints in HDPE pipes, a series of coupon tests have been completed for specimens cut from butt fused HDPE pipes with surface or subsurface flaws placed in the joints prior to fusion process. Specimens containing known flaw sizes were tested under axial load at accelerated stresses and temperatures until failure; or until a prescribed number of test hours was reached. The failure time from the tests has been correlated to the net section stress and the stress intensity factor, and the results showed that the failure time can be better represented by the stress intensity factor. The test results were then used to fit the Brown and Lu formula that predicts the time to failure due to the slow crack growth of flaws as a function of stress intensity factor and temperature. With the developed Brown and Lu equation, the allowable stress intensity factors for a piping lifetime of 50 years at the maximum code allowable temperature of 60°C have been proposed for both surface and subsurface flaws in HDPE butt fusion joints. Examples of what might be corresponding allowable flaw sizes in the butt fusion joints of piping are also provided.

Highly Reliable Software Reliability Assessment Based on Statistics of Extremes and Bootstrapping Method

2014 ◽  
Vol 670-671 ◽  
pp. 1477-1481
Author(s):  
Hao Nan Tong ◽  
Qiu Ying Li
Keyword(s):  
Software Reliability ◽  
Reliability Assessment ◽  
Time To Failure ◽  
Reliability Engineering ◽  
Statistics Of Extremes ◽  
Failure Data ◽  
Distribution Parameters ◽  
Extreme Distribution ◽  
Reliable Software ◽  
Bootstrapping Method

Reliability assessment of Highly Reliable Software is significant in the software reliability engineering because of the small-size failure data. A novel model based on bootstrapping method and statistics of extremes for highly reliable software reliability assessment was presented. Correlation coefficient method was applied in order to determine the extreme distribution pattern to which the failure data belongs. The bootstrapping method based on residual error was used to estimate the parent distribution parameters. Software reliability and mean-time-to-failure (MTTF) at the end of reliability test were assessed. Experimental results show the model has a higher accuracy in the small-size sample situation. The validity of the proposed method is examined.

scholarly journals Integration of FMECA and statistical snalysis for predictive maintenance

2021 ◽  
Vol 2 (1) ◽  
pp. 33
Author(s):  
Rabia Ghani
Keyword(s):  
Production Line ◽  
Manufacturing Industry ◽  
Failure Modes ◽  
Remaining Useful Life ◽  
Predictive Maintenance ◽  
Time To Failure ◽  
Failure Data ◽  
Criticality Analysis

<p>The estimation of time-to-failure of machines is of utmost importance in the Manufacturing Industry. As the world is moving towards Industry 4.0, it is high time that we progress from the traditional methods, where we wait for a breakdown to occur, to the prognostics based methods. It is the need of the era to be aware of any incident before it occurs. This study provides application of Statistical-based Predictive maintenance. A BOPP Production line has been considered as a case study for this research. Since the inception of the line in 2013, it is evident that 60% of breakdowns are due to lack of maintenance and timely replacement of bearings. Therefore, the research is based on the application of FMECA (Failure Modes, Effects and Criticality Analysis) to determine which bearing in the production line is most prone to failure and determination of which statistical model best fits the failure data of the most critical bearing. The result provides the best distribution fit for the failure data and the fit can be utilized for further study on RUL (Remaining Useful Life) of the bearing through Bayesian Inference.</p>

Aircraft turbines time-to-failures process modeling using RBF NN

2019 ◽  
Vol 26 (2) ◽  
pp. 249-259
Author(s):  
Ahmed Z. Al-Garni ◽  
Wael G. Abdelrahman ◽  
Ayman M. Abdallah
Keyword(s):  
Back Propagation ◽  
Computation Time ◽  
Aircraft Engine ◽  
Computational Time ◽  
Time To Failure ◽  
Content Type ◽  
Weibull Regression ◽  
Failure Data ◽  
Feed Forward Back Propagation ◽  
Accuracy Of Results

Purpose The purpose of this paper is to formulate a specialized artificial neural network algorithm utilizing radial basis function (RBF) for modeling of time to failure of aircraft engine turbines. Design/methodology/approach The model uses training failure data collected from operators of turboprop aircraft working in harsh desert conditions where sand erosion is a detrimental factor in reducing turbine life. Accordingly, the model is more suited to accurate prediction of life of critical components of such engines. The used RBF employs a closest neighbor type of classifier and the hidden unit’s activation is based on the displacement between the early prototype and the input vector. Findings The results of the algorithm are compared to earlier work utilizing Weibull regression modeling, as well as Feed Forward Back Propagation NN. The results show that the failure rates estimated by RBF more closely match actual failure data than the estimations by both other models. The trained model showed reasonable accuracy in predicting future failure events. Moreover, the technique is shown to have comparatively higher efficiency even with reduced number of neurons in each layer of ANN. This significantly decreases computation time with minimum effect on the accuracy of results. Originality/value Using RBF technique significantly decreases the computational time with minimum effect on the accuracy of results.

REVIEW OF FAN LIFE EVALUATION PROCEDURES

1996 ◽  
Vol 03 (01) ◽  
pp. 75-96 ◽  
Author(s):  
SUNG KIM ◽  
CARLOS VALLARINO ◽  
ALAN CLAASSEN
Keyword(s):  
Acoustic Noise ◽  
Failure Behavior ◽  
Time To Failure ◽  
Test Procedures ◽  
Failure Data ◽  
Evaluation Procedures ◽  
Accelerated Life ◽  
Designed Experiment ◽  
Life Tests ◽  
Definition Of

Improving the reliability of air cooled electronic equipment must include focusing on the life expectancy of the fans or blowers. Evaluating fan failure behavior, however, is not a trivial problem, as vendors report very little information on this subject. Even when product literature provides such data, one vendor’s results are generally impossible to compare with another’s due to different test procedures, different assumptions, and different calculation methods, not all of which are explicitly defined. This paper is designed to help thermal and component evaluation engineers who have been assigned the task of sorting through these sometimes conflicting, often incompatible, claims regarding fan quality. We start with a definition of fan failure in terms of rotational speed, running current, and acoustic noise. Some basic statistical principles, such as Weibull hazard rate, Mean Time To Failure (MTTF) and L10 life, are presented in the reliability section, leading into methods for the estimation of fan life. Booser’s equation for grease life is included and its limitations for modern greases are noted; the standard equation for bearing rating life is also covered. To verify calculated fan life estimates, a designed experiment may be performed. A basic formula for the design of a fan life experiment is given, together with a brief analysis of published failure data from such an experiment. Most fan life tests are conducted under stress conditions, such as high temperature, that accelerate fan failures. The final section discusses accelerated life testing, including potential pitfalls. Simulating a mini-textbook, the paper contains valuable everyday reference material, including sample calculations to illustrate the concepts reviewed.

scholarly journals Creep-Fatigue Behavior of Microelectronic Solder Joints

1991 ◽  
Vol 225 ◽  
Author(s):  
R. G. Ross ◽  
L. C. Wen ◽  
G. R. Mon ◽  
E. Jetter ◽  
J. Winslow
Keyword(s):  
Solder Joint ◽  
Solder Joints ◽  
Thermal Environment ◽  
Fatigue Behavior ◽  
Time To Failure ◽  
Test Fixture ◽  
Failure Data ◽  
Analytical Results ◽  
Creep Fatigue ◽  
Alloy Properties

ABSTRACTEven at room temperature, solder joints exhibit both creep and fatigue behavior that is strongly dependent on solder joint configuration, the thermal environment, and the solder alloy properties. The microstructures of solder joints with up to 25 years of aging have been studied using SEM/EDS and metallographic techniques. Data are presented on grain growth and metallurgical composition versus aging time. A special non-linear finite element creep-fatigue simulation model has been developed, based on measured strain-rate hardness relationships, and used to analytically predict the effects of observed metallurgical changes and the effects of lead stiffness in solder joint creepfatigue interaction. To corroborate the analytical results, a special bi-metallic test fixture has been developed to accelerate the thermo-mechanical loading of solder joints in thermal cycling environments. Measured time-to-failure data for various electronicpackage lead configurations/stiffnesses, including gullwing and J-lead, are presented and shown to be in reasonable agreement with the analytical results.

scholarly journals Reliability Analysis for Unrepairable Automotive Components

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7014
Author(s):  
Dariusz Ulbrich ◽  
Jaroslaw Selech ◽  
Jakub Kowalczyk ◽  
Jakub Jóźwiak ◽  
Karol Durczak ◽  
...  
Keyword(s):  
Time To Failure ◽  
Technical Object ◽  
Reliability Characteristic ◽  
Preventive Replacement ◽  
Automotive Components ◽  
Reliability Parameters ◽  
Failure Data ◽  
Preventive Actions ◽  
Distribution Parameters ◽  
Cost Parameters

The analysis of the reliability parameters of a technical object and the determination of the change in the reliability of the object over time, requires the knowledge of the functional characteristics and reliability parameters of the elements included in a system. On the basis of the failure data of the selected element of the object, in this case the vehicle, it is possible to determine the average working time to failure of the element and the appropriate form of distribution that characterizes the reliability and durability parameters of the tested element. The main purpose of the research presented in the article was to develop a method of assessing the reliability of an electronic component of a vehicle-a boot lid contactor. This paper also presents three possible methods of repairing the boot lid contactor (sealing the housing with adhesive with better way, replacing the element with a new one or the most time-consuming solution, changing the shape of the boot lid). The authors also decided to determine the reliability and cost parameters that will allow preventive replacement of this element. The tests were carried out on a fleet of 61 vehicles of the same model, but with different body structures. Contactor failures were reported in 41 cases, of which 29 were in the hatchback construction and 12 in the estate type. The analysis of the distribution selection for the tested part of the passenger car-the boot lid contactor-was performed using the Likelihood Value (LKV) test to determine the rank of distributions. Also the maximum likelihood (MLE) method was used to estimate the distribution parameters. The three-parameter Weibull distribution was the best-fitted distribution in both cases. It was clearly defined that one model of car with two different types of body have vastly different reliability characteristic. Based on the reliability characteristic and parameters, the appropriate preventive actions can be taken, minimizing the risk of damage, thus avoiding financial losses and guaranteeing an appropriate level of vehicle safety.

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