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.

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.

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.

scholarly journals Modelling Reliability Characteristics of Technical Equipment of Local Area Computer Networks

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 955
Author(s):  
Vasyl Teslyuk ◽  
Andriy Sydor ◽  
Vincent Karovič ◽  
Olena Pavliuk ◽  
Iryna Kazymyra
Keyword(s):  
Large Scale ◽  
Computer Network ◽  
Network Reliability ◽  
Local Area ◽  
Technical Equipment ◽  
Time To Failure ◽  
Reliability Parameters ◽  
Reliability Characteristics ◽  
Global World ◽  
Level 2

Technical systems in the modern global world are rapidly evolving and improving. In most cases, these are large-scale multi-level systems and one of the problems that arises in the design process of such systems is to determine their reliability. Accordingly, in the paper, a mathematical model based on the Weibull distribution has been developed for determining a computer network reliability. In order to simplify calculating the reliability characteristics, the system is considered to be a hierarchical one, ramified to level 2, with bypass through the level. The developed model allows us to define the following parameters: the probability distribution of the count of working output elements, the availability function of the system, the duration of the system’s stay in each of its working states, and the duration of the system’s stay in the prescribed availability condition. The accuracy of the developed model is high. It can be used to determine the reliability parameters of the large, hierarchical, ramified systems. The research results of modelling a local area computer network are presented. In particular, we obtained the following best option for connecting workstations: 4 of them are connected to the main hub, and the rest (16) are connected to the second level hub, with a time to failure of 4818 h.

Overview of Wind Turbine Field Failure Databases: A Discussion of the Requirements for an Analysis

2018 ◽  
Author(s):  
Roozbeh Bakhshi ◽  
Peter Sandborn
Keyword(s):  
Statistical Analysis ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farms ◽  
Onshore Wind ◽  
Failure Times ◽  
Reliability Parameters ◽  
Failure Data ◽  
Offshore Installations ◽  
Field Failure

With renewable energy and wind energy in particular becoming mainstream means of energy production, the reliability aspect of wind turbines and their sub-assemblies has become a topic of interest for owners and manufacturers of wind turbines. Operation and Maintenance (O&M) costs account for more than 25% of total costs of onshore wind projects and these costs are even higher for offshore installations. Effective management of O&M costs depends on accurate failure prediction for turbine sub-assemblies. There are numerous models that predict failure times and O&M costs of wind farms. All these models have inputs in the form of reliability parameters. These parameters are usually generated by researchers using field failure data. There are several databases that report the failure data of operating wind turbines and researches use these failure data to generate the reliability parameters through various methods of statistical analysis. However, in order to perform the statistical analysis or use the results of the analysis, one must understand the underlying assumptions of the database along with information about the wind turbine population in the database such as their power rating, age, etc. In this work, we analyze the relevant assumptions and discuss what information is required from a database in order to improve the statistical analysis on wind turbines’ failure data.

Early Warning from Car Warranty Data using a Fuzzy Logic Technique

2010 ◽  
pp. 347-364
Author(s):  
Mark Last ◽  
Yael Mendelson ◽  
Sugato Chakrabarty ◽  
Karishma Batra
Keyword(s):  
Early Warning ◽  
Cognitive Model ◽  
Human Perception ◽  
General Motors ◽  
Time To Failure ◽  
Frequency Distributions ◽  
Empirical Distributions ◽  
Preventive Actions ◽  
Warranty Claims ◽  
Fuzzy Logic Technique

Car manufacturers are interested to detect evolving problems in a car fleet as early as possible so they can take preventive actions and deal with the problems before they become widespread. The vast amount of warranty claims recorded by the car dealers makes the manual process of analyzing this data hardly feasible. This chapter describes a fuzzy-based methodology for automated detection of evolving maintenance problems in massive streams of car warranty data. The empirical distributions of time-to-failure and mileage-to-failure are monitored over time using the advanced, fuzzy approach to comparison of frequency distributions. The authors’ fuzzy-based early warning tool builds upon an automated interpretation of the differences between consecutive histogram plots using a cognitive model of human perception rather than “crisp” statistical models. They demonstrate the effectiveness and the efficiency of the proposed tool on warranty data that is very similar to the actual data gathered from a database within General Motors.

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

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.

scholarly journals Parametric evaluation of the technical object suitability based on analyze the quality of its maintenance and use taking into account the initial conditions

2018 ◽  
Vol 182 ◽  
pp. 01006
Author(s):  
Rafał Grądzki
Keyword(s):  
Equations Of State ◽  
Initial Conditions ◽  
Technical Condition ◽  
Operation Condition ◽  
Technical Object ◽  
Coupled Equations ◽  
Reliability Parameters ◽  
Operation Conditions ◽  
Operational Data

In this paper, the comparison of three various technical objects (engines of public transport buses) exploitation research for different initial conditions are presented. Object researches were carried out in 2012 and then repeated in 2013. Gathered operational data is presented in three sets (1 – concerning object, 2 – concerning driving conditions, 3 – concerning driver, where set 1 is the collection of diagnostic information Dk, and sets 2 and 3 are the information about object environment U) in form of conventional points (experts numerical assessments). Relation between point information of object and point information of environment was described by coupled equations of state (describing relations between operation condition and technical condition including initial conditions for each analyzed exploitation period). That method allows to determine parameters of technical condition aT and operation condition aR and next, from the course of aT parameter, set of parametrical damage mT(t) and from course of parameter aR – set of momentary damage aR(t). Thus it is possible to evaluate exploitation, technical and operation conditions of each object (bus engine). Received reliability parameters allows to properly control exploitation and service of particular objects and set of objects (fleet of buses) and its elements.

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