Prediction of Failure Rate of Rotary Machine Using Computer Simulations

2005 ◽  
Vol 127 (4) ◽  
pp. 768-772 ◽  
Author(s):  
Jie Chen ◽  
Gang Bai ◽  
Zhongmin Shen ◽  
Xiaofeng Li ◽  
David Fulton ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Failure Rate ◽  
Computer Simulations ◽  
Design Phase ◽  
Rotary Machine ◽  
Rotary Machines

Failures can occur in brushless alternators due to interferences between the moving and stationary parts, called “rub.” Improper design of component target dimensions and tolerances can result in interferences. A method was developed to evaluate the component tolerances that can create interference in a brushless alternator. Mathematic models were created to relate target dimensions to the interferences. Monte Carlo simulation was utilized to statistically evaluate the effects of tolerances on failure rate. This method allows a designer to avoid potential rub failures while still in the design phase. It can also be used to analyze rotary machines of similar designs.

Ship Damage Stability Approval Document Generation by a Amonte Carlo Method

2021 ◽  
Author(s):  
Stefan Krüger ◽  
Katja Aschenberg
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Information Needs ◽  
Computational Time ◽  
Strong Impact ◽  
Design Phase ◽  
Efficient Design ◽  
Stability Problems ◽  
Initial Design ◽  
Damage Stability

Abstract The revised SOLAS 2020 damage stability regulations have a strong impact on possible future ship designs. To cope with these requirements, damage stability investigations must become a central part of the initial design phase, and many internal subdivision concepts need to be investigated. Unfortunately, if damage stability calculations are performed in the classical way, they are very time consuming with respect to modelling and computational time. This fact has impeded the consequent subdivision optimization in the past. Therefore, a simulation procedure for damage stability problems was developed which treats damage stability as a stochastic process which was modeled by a Monte Carlo simulation. If statistical damage distributions are once known, the Monte Carlo simulation delivers a population of damages which can be automatically related to certain damage cases. These damage cases can then be investigated with respect to their survivability. Applying this principle to damage stability problems reduces the computational effort drastically where at the same time no more manual modelling is required. This development does especially support the initial design phase of the compartmentation and leads to a safer and more efficient design. If this very efficient simulation principle shall now also be used after the initial design phase for the generation of approval documents, additional information needs to be generated by the simulation method which is not directly obtained during the simulation: This includes detailed individual probabilities in all three directions and the integration of all damage cases into predefined damage zones. This results in fact in a kind of reverse engineering of the manual damage stability process to automatically obtain this required information. It can be demonstrated that the time to obtain the final documents for the damage stability approval can be drastically reduced by implementing this principle.

scholarly journals Monte Carlo Simulation of Some Dynamical Aspects of Drop Formation

1997 ◽  
Vol 08 (05) ◽  
pp. 1073-1080 ◽  
Author(s):  
A. R. de Lima ◽  
T. J. P. Penna ◽  
P. M. C. de Oliveira
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Computer Simulations ◽  
Microscopic Level ◽  
Drop Formation ◽  
Additional Advantage

In this work we present some results from computer simulations of dynamical aspects of drop formation in a leaky faucet. Our results, which agree very well with the experiments, suggest that only a few elements, at the microscopic level, would be necessary to describe the most important features of this system. We were able to set all parameters of the model in terms of real ones. This is an additional advantage with respect to previous theoretical works.

Evaluation of Stopping Rules for Audiological Ascending Test Procedures Using Computer Simulations

1989 ◽  
Vol 32 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Lynne Marshall ◽  
Thomas E. Hanna
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Psychometric Function ◽  
Computer Simulations ◽  
Stopping Rules ◽  
Response Criterion ◽  
Small Decrease ◽  
Test Procedures ◽  
Minimum Number ◽  
Audiological Test

Stopping rules for ascending audiological test procedures were evaluated by Monte Carlo simulation. The stopping rules differed in the minimum number of responses required at a level, whether these responses occurred on half or a majority of the ascending series, and whether all or only the most recent ascending series were considered. For all procedures, shallow psychometric function slopes yielded estimated thresholds closer to the level giving 50% detection than did steeper slopes, which yielded estimated thresholds roughly 2.5 dB above the level corresponding to 50% on the psychometric function. Shallow slopes also resulted in decreased reliability across threshold measurements, an increased number of trials required for threshold estimates, and a higher proportion of measurements that had to be repeated. Stopping rules using a two-response criterion were faster than those using a three-response criterion, with only a small decrease in reliability. Among stopping rules using the same number of responses for criterion, differences were seen primarily in efficiency for shallow slopes, particularly for procedures using a three-response rather than a two-response criterion for stopping. Results from these simulations should be useful to standards groups.

scholarly journals Computer non-iterative data acquisition of particle trajectory in a spark chamber

2019 ◽  
Vol 34 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Vladimir Poluzanski ◽  
Aleksandar Zigic ◽  
Dragan Kovacevic ◽  
Bosko Nikolic
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Iterative Algorithm ◽  
Computer Simulations ◽  
Particle Trajectory ◽  
Simulation Method ◽  
Monte Carlo Simulation Method ◽  
Charge Particle ◽  
Particle Localization ◽  
Computational Resources

This paper presents a novel non-iterative algorithm for charge particle localization in a spark chamber. Its performance is evaluated by computer simulations using the Monte Carlo simulation method and compared with the performance of an appropriate iterative algorithm. It is found that the proposed non-iterative algorithm performs significantly better, is easier to implement and requires less computational resources than the iterative algorithm.

scholarly journals Non-linear failure rate: A Bayes study using Hamiltonian Monte Carlo simulation

2020 ◽  
Vol 123 ◽  
pp. 55-76 ◽  
Author(s):  
Tien T. Thach ◽  
Radim Bris ◽  
Petr Volf ◽  
Frank P.A. Coolen
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Failure Rate ◽  
Hamiltonian Monte Carlo ◽  
Non Linear

Monte Carlo Simulation of the Initial Disordering Rate of Cu3Au Under Ion Irradiation

1998 ◽  
Vol 527 ◽  
Author(s):  
L.C. Wei ◽  
E. Lang ◽  
M. Ghaly ◽  
P. Bellon ◽  
R. S. Averback
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Temperature Dependence ◽  
Computer Simulations ◽  
Monte Carlo Methods ◽  
Ion Irradiation ◽  
Atomic Mixing ◽  
Present Simulation

ABSTRACTThe temperature dependence of disordering of Cu3Au during ion irradiation has been investigated by computer simulations using MONTE CARLO methods. The investigation was motivated by peculiar experimental observations that the initial disordering rate begins to decrease above ~300 K, which can be explained by vacancies just becoming mobile at that temperature, but then at ~ 475 K, it reaches a minimum and then increases rapidly as the temperature is further increased, up to the order-disorder temperature. The present simulation shows that this behavior can be understood in terms of temperatures dependencies in both atomic mixing in the cascade and the efficiency of vacancy annealing of disorder as the vacancies diffuse out of the cascade.

Failure of the “Kick-Out” Model for the Diffusion of Au into Si when Tested by Monte Carlo Simulation

1989 ◽  
Vol 163 ◽  
Author(s):  
U. Schmid ◽  
J. A. Van Vechtent ◽  
N. C. Myers ◽  
U. Koch
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Computer Program ◽  
Computer Simulations ◽  
Large Scale ◽  
Controversial Issue ◽  
Monte Carlo Algorithm ◽  
Atom Level ◽  
Working Out

AbstractWe have performed large scale computer simulations on the controversial issue of Au diffusion into Si at T = 1095° C. Using a Monte Carlo algorithm and a conveniently parametrized set of parameters, our computer program is capable of working out the macroscopic consequences of a variety of models, i.e. atom level assumptions, in an unbiased way and without the approximations introduced in analytic calculations.When applied to the “kick-out” hypothesis, our results are dramatically at odds with the properties claimed by its proponents. Neither the profile of the Au substitutionals, nor the Au-interstitial profiles are in agreement with the analytically obtained results. The discrepancy becomes most pronounced when comparing the variation with time of the Au concentration in the center of the sample, which we find to be linear at all times, in contrast to the alleged t1/2 behavior. Moreover, the Au profile of a one-sided diffusion never becomes U-shaped, as experimentally observed.

Electron Scattering in Solids

1990 ◽  
Vol 48 (2) ◽  
pp. 4-5
Author(s):  
Ryuichi Shimizu ◽  
Ze-Jun Ding
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Angular Distribution ◽  
Elastic Scattering ◽  
Electron Scattering ◽  
Cross Sections ◽  
Expansion Method ◽  
Electron Excitation ◽  
Partial Wave Expansion ◽  
Backscattered Electrons

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

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