Estimation of Weibull distribution parameters for irregular interval group failure data with unknown failure times

1998 ◽  
Vol 25 (2) ◽  
pp. 207-219
Author(s):  
A. B. M. Zohrul Kabir
Keyword(s):  
Weibull Distribution ◽  
Interval Group ◽  
Failure Times ◽  
Failure Data ◽  
Irregular Interval ◽  
Distribution Parameters ◽  
Group Failure

Engine Failure Data Analysis Method Based on Weibull Distribution Model

2011 ◽  
Vol 128-129 ◽  
pp. 850-854
Author(s):  
Ying Kui Gu ◽  
Jing Li
Keyword(s):  
Weibull Distribution ◽  
Distribution Model ◽  
Parallel Model ◽  
Analysis Method ◽  
Failure Data ◽  
Rod System ◽  
Distribution Parameters ◽  
Engine Failure ◽  
Engine Reliability ◽  
Drawing Method

The failure data of crank rod system was analyzed by using weibull parallel model on the base of the simple weibull method. The distribution parameters of the weibull parallel model were estimated by using drawing method. The solving process of WPP drawing method was given in detial. Results show that the fitting degree of the failure data in the weibull parallel model is higher than that of the simple weibull distribution model, and it can more accurately described the failure distribution curve of the system in life cycle, which can provide necessary information for engine reliability indexes computation.

Railway Equipment Reliability Test Based on Weibull Distribution

2016 ◽  
Vol 851 ◽  
pp. 340-345 ◽  
Author(s):  
Ce Liang ◽  
Jian Wei Yao ◽  
Ke Xin Zhang ◽  
Ze Ping Zhao
Keyword(s):  
Weibull Distribution ◽  
Rank Order ◽  
Least Square Method ◽  
Sampling Plan ◽  
Least Square ◽  
Reliability Test ◽  
Failure Data ◽  
Equipment Reliability ◽  
Interval Censored ◽  
Distribution Parameters

This paper presents a new approach for reliability test sampling plan of Railway equipment. Based on the interval censored failure data, the mean rank order method is used for data pre-process and the least square method is used for fitting the parameters of Weibull distribution, where, the best estimations of distribution parameters are derived. The sampling inspection plan for interval censored data is established when the lifetime follows the Weibull distribution. In the case study, we applied the proposed method to design the reliability test sampling plan of an electric multiple units.

Calculation of Weibull Distribution parameters at low wind speed and performance analysis

2021 ◽  
pp. 1-24
Author(s):  
Yusuf Alper Kaplan
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Weibull Distribution ◽  
Energy Potential ◽  
Average Wind Speed ◽  
Statistical Indicator ◽  
Low Wind Speed ◽  
Distribution Parameters ◽  
Wind Energy Potential ◽  
And Performance

In this study, the compatibility of the real wind energy potential to the estimated wind energy potential by Weibull Distribution Function (WDF) of a region with low average wind speed potential was examined. The main purpose of this study is to examine the performance of six different methods used to find the coefficients of the WDF and to determine the best performing method for selected region. In this study seven-year hourly wind speed data obtained from the general directorate of meteorology of this region was used. The root mean square error (RMSE) statistical indicator was used to compare the efficiency of all used methods. Another main purpose of this study is to observe the how the performance of the used methods changes over the years. The obtained results showed that the performances of the used methods showed slight changes over the years, but when evaluated in general, it was observed that all method showed acceptable performance. Based on the obtained results, when the seven-year data is evaluated in this selected region, it can be said that the MM method shows the best performance.

scholarly journals New Estimators for Weibull Distribution Parameters: Comprehensive Comparative Study for Weibull Distribution

2019 ◽  
Vol 16 (1) ◽  
pp. 33-57
Author(s):  
Sahar sadani ◽  
Kamel abdollahnezhad ◽  
mahdi teimouri ◽  
Vahid ranjbar ◽  
◽  
...  
Keyword(s):  
Comparative Study ◽  
Weibull Distribution ◽  
Distribution Parameters

A New Technique for Optimization of Product Acceptance Process in Terms of Misclassification Probability

2018 ◽  
pp. 1-32
Author(s):  
Nicholas A. Nechval ◽  
Konstantin N. Nechval
Keyword(s):  
Weibull Distribution ◽  
Optimization Technique ◽  
Parametric Uncertainty ◽  
Lifetime Distribution ◽  
Statistical Quality Control ◽  
Misclassification Probability ◽  
Distribution Parameters ◽  
A New Technique ◽  
Two Parameter

A product acceptance process is an inspecting one in statistical quality control or reliability tests, which are used to make decisions about accepting or rejecting lots of products to be submitted. This process is important for industrial and business purposes of quality management. To determine the optimal parameters of the product acceptance process under parametric uncertainty of underlying lifetime models (in terms of misclassification probability), a new optimization technique is proposed. The most popular lifetime distribution used in the field of product acceptance is a two-parameter Weibull distribution, with the assumption that the shape parameter is known. Such oversimplified assumptions can facilitate the follow-up analyses, but may overlook the fact that the lifetime distribution can significantly affect the estimation of the failure rate of a product. Therefore, the situations are also considered when both Weibull distribution parameters are unknown. An illustrative numerical example is given.

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.

scholarly journals Analysis of Three-Dimensional Damage Constitutive Model of Frozen Sand Based on the Influence of Intermediate Principal Stress and Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Shilong Ma ◽  
Zhaoming Yao ◽  
Shuang Liu ◽  
Xuan Pan
Keyword(s):  
Constitutive Model ◽  
Weibull Distribution ◽  
Principal Stress ◽  
Three Dimensional ◽  
Intermediate Principal Stress ◽  
Frozen Soil ◽  
Stress Coefficient ◽  
Frozen Sand ◽  
Distribution Parameters ◽  
Damage Constitutive Model

To study the mechanical properties of frozen soil, it is necessary to understand the damage characteristics of frozen soil. Four types of three-dimensional indoor tests of frozen sand were carried out at −5°C, −10°C, and −15°C to study the mechanical damage properties. These include different stress path tests with the principal stress coefficients of 0, 0.25, 0.5, and 0.75 while analyzing the entire failure process. First, the three-dimensional compression test of frozen sand was studied to analyze the influence of temperature and intermediate principal stress coefficient on the large principal stress of frozen soil. The damage cost of frozen sand under the influence of different temperatures and intermediate principal stress coefficients was also established. Second, using the characteristics of discreteness and randomness of the distribution of the microelements inside the frozen soil and assuming that the failure of the microelement of the frozen soil obeys the Weibull distribution, the Drucker–Prager strength criterion was used as the statistical distribution variable of the microelement of the frozen soil based on the strain equivalence hypothesis, statistical theory, and continuous damage mechanics. This allows for a constitutive model of frozen sand damage under the three-dimensional stress state to be established. Finally, the model parameter values through low-temperature three-dimensional test data were able to be determined. This model allows for the physical meaning of Weibull distribution parameters F0 and m to be analyzed, and the distribution parameters with temperature and intermediate principal stress coefficient can be modified to obtain a modified frozen sand damage constitutive model. The results show that the modified damage constitutive model can simulate the entire process curve of the large principal stress-strain of frozen sand. It shows that the large principal stress of frozen sand increases with the increase of temperature and intermediate principal stress coefficient. Concurrently, the frozen sand damage constitutive model proposed in this paper can describe the deformation behavior of frozen soil under different temperature and stress paths and can be adapted to various other sediment types.

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