Papers by Keyword: Monte-Carlo

Abstract: Reliability of eccentric wear casing was studied by Monte-Carlo and finite element method. In different internal pressures, calculated reliability of P110 steel grade 9 ⁵/₈ inches casing with wear depth less than 0.5 times wall thickness. The influence of different cement ring circumferential missing amount and stratum pressures on wear casing reliability were presented. The results provide basis for casing safety evaluation and reasonable replacement.

Abstract: The objective of this study was to assess the feasibility of noninvasive alcohol testing in vivo with near-infrared (NIR) spectroscopy. The suitable distance between light source and detector was determined by Monte-Carlo simulation. The NIR spectra signals of alcohol in vitro and in vivo were measured, and the blood alcohol concentration (BAC) was measured with breath test method. Wavelet de-noising and partial least squares (PLS) method were used to establish the quantitative calibration model of alcohol. The results indicate that alcohol spectra had two absorption peaks at range of 2200nm～2400nm. The optimal principal component number of PLS model is 3, RMSEP=9.29, MREP=3.5%，R=0.9802. The model has good prediction accuracy. NIRS might provide a new method to the measurement of alcohol in vivo.

Abstract: Condition-based Maintenance (CBM), which can efficiently improve the performance of the deteriorating system, would be influenced by imperfect inspection in practice. Aiming at this problem, a new CBM model under imperfect inspection is presented for deteriorating system, which described by Gamma process. The system is inspected periodically, and a preventive maintenance is performed if the degradation level exceeds a threhold. The inspection is imperfect, that means the measurements contain errors, and the CBM model should take these measure errors into account. The algorithm is shown to estimate the long run cost rate using Monte-Carlo method. Through numerical example, the influence of mesurement error over long run cost is analyzed. Therefore, the correctness and rationality of the model are proved.

Abstract: In order to analyse bridge structure system reliability, studied various uncertainty factors on the influence of the bridge reliability, using the stochastic finite element method to analyse bridge reliability, according to the influence of bridge structure reliability uncertainty factors, including geometric parameter uncertainty, material properties uncertainty, the bridge weights uncertainty and the vehicle load uncertainty.According to the bridge actual working condition, respectively used stress and deflection deformation as the bridge structure safety control index, established 2 each reliability function, that is, considered the structure of the two failure mode.Using Monte-Carlo method to analyze the bridge structure reliability, verify the reliability analysis method is feasible, the bridge reliability about sensitivity factors, and provides the basis for the bridge structure reliability analysis.

Abstract: Condition-based Maintenance (CBM) can not only efficiently improve the performance of deteriorating system but also guarantee the system operation safety. This paper assumes that the system state is periodically inspected, and a preventive maintenance is performed if the degradation level exceeds a threshold. The effect of maintenance is imperfect, which means that maintenance can restore the system state to somewhere between as good as new and as bad as old. The algorithm is presented to get the solution of long run cost based on Monte-Carlo simulation, and the joint optimization of inspection rate, the threshold value and the number of preventive maintenance activities is investigated for the minimization of long run cost rate. A case study is given to show the procedure of the maintenance model and simulation. Therefore, the correctness and rationality of the model are proved.

Abstract: In order to confirm the structure strength reliability of the plunger pump fluid end, the 3-D parametric finite element model is built according to its structure characteristic, the finite element analysis is carried through the finite element analysis software, and the reliability analysis is carried by ANSYS/PDS. The analysis result shows that 500 times sampling simulation suffices the need of precision. The result of sensitivity analysis is shown that the main influencing factor is material yield limit of plunger pump for the reliability, the second is the internal pressure of fluid end, and the elastic modulus and Poisson ratio have less effect for the reliability. The reliability of fluid end is 95.6% when the material yield limit of plunger pump is normal distribution. The reliability of fluid end is up to 100% when the material yield limit is constant, so the material yield limit is ensured not change when the fluid end is designed and manufactured.

Abstract: The paper presents a method used to model rock as continuous media with discontinuous joints. The Monte-Carlo method is employed in simulating the joint network of jointed rock mass based on certain principles, and the calculation method on the mechanical persistence ratio is studied, furthermore, some research on the influential factors on the persistence ratio is performed, and the values of some empirical parameters are obtained, which assured the stability of the results.

Abstract: In this paper, experimental results and Monte Carlo simulation methods used to study irradiation damage of Electron-beam on high-power AlInGaP red LED. The electron beam range and distribution of energy loss in the LED chip are analyzed by CASINO program in detail, the high-power AlInGaP red LED is irradiated by different energy and dose of electron beam irradiation produced by the low energy electron beam irradiation equipment. We contrast the optical parameter of the irradiated LED with the unirradiated LED. The experimental result is analyzed and discussed by the mechanism of electron beam irradiation. The results show that: the luminous flux and power change of the irradiated and unirradiated LED are showed by dose-response. In process of irradiation, the elastic collision and ionization are occurred between the incident particles and atoms within the material, which cause defect in the internal structure of the AlInGaP material and form the color centers.

Abstract: The present contribution focuses on a recently developed model of microstructure evolution. The model is based on a phase field approach, which takes account of kinetic effects in solidification of alloys and intermetallic compounds. It further incorporates crystal orientation as an additional field variable, which evolves through a Monte-Carlo algorithm. Combination of the phase field approach with Monte-Carlo algorithm allows for physically meaningful and computationally effective simulation of microstructure in polycrystalline and intermetallic forming systems. The paper includes various examples of simulated microstructures in different thermal processes.

Abstract: The safety of the pipeline in use is tightly linked with the resident life and belongings. Reliable structural integrity and safety of gas pipelines under various service pressure events including defects should be warily evaluated. The reliability evaluation of gas pipelines is necessary to prevent risk. In this paper, Markov chain Monte Carlo is proposed to analyze the reliability of factors affecting gas pipeline operational condition in consideration of the character of historical data, the calculating processes of reliability prediction are provided in view of performance degradation characteristics of the factors.This paper takes corrosion as important factor affecting pipeline operation for example, calculates the reliability indexes of gas pipeline, studies the relation of failure rate and length/depth of corrosion pit ,operation time,etc. seeks weak links of system, and brings forward concrete and reliable measures to improve system reliability.