A Statistical Adaptable Distribution Function Model for Low Probabilities of Failure

1993 ◽  
Author(s):  
Suryaji R. Bhonsle ◽  
Paul Thompson
Keyword(s):  
Experimental Data ◽  
Distribution Function ◽  
Experimental Results ◽  
Function Model ◽  
Log Normal ◽  
Function Models

Abstract Weibull, log normal, and some other Distribution function models (D.F.M.) have a tendency to deviate from experimental results. This deviation, either exceedingly conservative or nonconservative, is amplified at low probabilities of failure. To remedy such problems a new D.F.M. is derived. It is then used to predict low probabilities of failure. The predictions are consistent with experimental data and are not too conservative or too nonconservative.

Statistical and Mathematical Approach for Distribution Function Model for Low Probability of Failures

1991 ◽  
Author(s):  
S. R. Bhonsle ◽  
C. V. VanKarsen ◽  
J. R. Michler
Keyword(s):  
Distribution Function ◽  
Statistical Models ◽  
Mathematical Approach ◽  
Probabilistic Design ◽  
Function Model ◽  
Lower Tail ◽  
Low Probability ◽  
Statistical Distribution Function ◽  
Function Models ◽  
Design Factors

In probabilistic design it is common practice to use statistical models such as normal, lognormal, and Weibull to describe random design factors. However these distribution function models deviate in the lower tail, i.e. percentiles below 1%. The deviation is nonconservative in that since it predicts life longer than observed. A Statistical Distribution Function called Adaptive Distribution Function Model similar to Abelkis model was developed. It is compatible with the collected data, and it produces conservative designs at low tail ends. It is also relatively easy to use.

Modeling Dislocation Loop Nucleation and Evolution in Germanium, Arsenic and Boron Implanted Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
Ibrahim Avci ◽  
Mark E. Law
Keyword(s):  
Experimental Data ◽  
Normal Distribution ◽  
Dislocation Loop ◽  
Evolution Model ◽  
Experimental Results ◽  
Projected Range ◽  
Defect Nucleation ◽  
Log Normal ◽  
Log Normal Distribution

AbstractA loop nucleation and evolution model in Si+ implanted Silicon was previously introduced [1]. In this study, the model is extended to predict end of range (EOR) and projected range defect nucleation and evolution created by different ion implant species such as Germanium, Arsenic and Boron. The model assumes that all the nucleated loops come from {311} unfaulting and the loop density and average loop radius follow a log normal distribution. The model is verified with the experimental data obtained from literature for Germanium [2], Arsenic [3] and Boron [4] implanted Silicon for different implant doses and energies. Modeling results are in agreement with the experimental results.

scholarly journals Study on Dielectric Function Models for Surface Plasmon Resonance Structure

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Peyman Jahanshahi ◽  
Mostafa Ghomeishi ◽  
Faisal Rafiq Mahamd Adikan
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element ◽  
Surface Plasmon Resonance ◽  
Dielectric Properties ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Resonance Structure ◽  
Function Model ◽  
Function Models

The most common permittivity function models are compared and identifying the best model for further studies is desired. For this study, simulations using several different models and an analytical analysis on a practical surface Plasmon structure were done with an accuracy of∼94.4% with respect to experimental data. Finite element method, combined with dielectric properties extracted from the Brendel-Bormann function model, was utilized, the latter being chosen from a comparative study on four available models.

scholarly journals Peculiarities of data processing for optical measurements of disperse parameters of bimodal media

2019 ◽  
Vol 43 (4) ◽  
pp. 692-698 ◽  
Author(s):  
A.A. Zhirnov ◽  
O.B. Kudrjashova
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Distribution Function ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Normal Distribution ◽  
Size Distribution ◽  
A Priori ◽  
Log Normal ◽  
Log Normal Distribution

This study is focused on enhancing the informativity of optical measurement techniques for particulate matter. The problem is that the description of particulate matter with bimodal and multimodal distributions by an a priori defined analytical function of particle size distribution (for example, a log-normal distribution) is not accurate enough. Here, we explore if experimental data can be approximated by a multivariable function of particle size distribution instead of using the a priori defined log-normal distribution. For the comparison of the approximation results, experiments are conducted on standard samples with granulometric compositions OGS-01LM and OGS-08LM separately and jointly in a mix. The experimental data are recorded by a high-selectivity turbidimetric technique in water suspensions of these samples. The purpose of this study is to present the measurement results as a distribution function that enables one to identify more accurately the particle-size distribution profile and the corresponding disperse characteristics of the aerosol in question when measuring parameters of disperse media by optical techniques. The main objective of this work is to develop, implement and verify a search algorithm for the particle-size distribution function by way of a multi-parameter function. We show that the solution to the problem proposed herein is more universal because it allows slow and fast processes in suspensions and aerosols to be examined with a lower error. The algorithm can be applied to the problems which are based on solving first-kind Fredholm equations.

A Large Scale Fatigue Test of Aluminium Specimens

1965 ◽  
Vol 16 (4) ◽  
pp. 307-322 ◽  
Author(s):  
N. T. Bloomer ◽  
T. F. Roylance
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Normal Distribution ◽  
Probability Of Failure ◽  
Distribution Functions ◽  
Experimental Results ◽  
Normal Distribution Function ◽  
The Mean ◽  
Log Normal ◽  
Log Normal Distribution

SummaryThere have been, in the past, many fatigue tests carried out on a variety of materials and components. These all indicate a wide scattering in the lives (measured by the number of stress cycles to failure) endured by nominally identical components subjected to nominally identical forces before failure occurs. To interpet this scattering several equations have been suggested as representing the statistical distribution functions that fit the lives obtained for individual types of component. Of these functions the log normal distribution function has been perhaps the most widely used. For the central regions of the probability distribution, i.e. about the mean, the log normal distribution and several others represent experimental results very closely indeed, but engineers and designers of all kinds dare not design on the mean fatigue life. They are concerned with specifications that either exclude the possibility of failure or admit only a very small probability of failure. It is thus with the accuracy with which the “lower tail” of the probability distribution curve fits the experimental results that they are concerned.To assess the fit at this lower end for one type of component, a large number (about 1,000) of aluminium specimens have been tested and the corresponding lives plotted. The results are very interesting. They show clearly that the log normal distribution for this type of component and material is pessimistic for a probability of failure of less than 0·3. This result is felt by the authors to be of very great importance. It has further been shown that the use of the “one-sided censored distribution function”, used previously by one of the authors, gives a curve that will fit the lower results better than the complete log normal distribution would do.It is with the testing procedure adopted, the specimens used, the distribution functions considered and the conclusions obtained therefrom that this paper is concerned.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

Initiation and Statistical Evolution of Horizontal Slug Flow With a Two-Fluid Model

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
A. O. Nieckele ◽  
J. N. E. Carneiro ◽  
R. C. Chucuya ◽  
J. H. P. Azevedo
Keyword(s):  
Experimental Data ◽  
Slug Flow ◽  
Fluid Model ◽  
Subsequent Development ◽  
Complex Flow ◽  
Horizontal Pipes ◽  
Dimensional Version ◽  
Two Fluid Model ◽  
Log Normal ◽  
Two Fluid

In the present work, the onset and subsequent development of slug flow in horizontal pipes is investigated by solving the transient one-dimensional version of the two-fluid model in a high resolution mesh using a finite volume technique. The methodology (named slug-capturing) was proposed before in the literature and the present work represents a confirmation of its applicability in predicting this very complex flow regime. Further, different configurations are analyzed here and comparisons are performed against different sets of experimental data. Predictions for mean slug variables were in good agreement with experimental data. Additionally, focus is given to the statistical properties of slug flows such as shapes of probability density functions of slug lengths (which were represented by gamma and log-normal distributions) as well as the evolution of the first statistical moments, which were shown to be well reproduced by the methodology.

Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers

2009 ◽  
Author(s):  
Farrokh Zarifi-Rad ◽  
Hamid Vajihollahi ◽  
James O’Brien
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Axial Flow ◽  
Experimental Results ◽  
Scale Model ◽  
Data Set ◽  
Pressure Profiles ◽  
Scale Models ◽  
Inlet Conditions

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.

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