易燃易爆环境撬装清洗设备的安全可靠性分析与应用研究

针对石化领域易燃易爆环境下撬装清洗设备的安全可靠性要求,从撬装清洗设备易燃易爆环境JSA作业风险评估及控制出发,分析危害程度大的燃烧爆炸安全风险及发生概率较高的运输安全风险,提出易燃易爆和运输安全性设计方法和判定依据;基于故障模式及危害性分析(FMECA),建立水射流清洗系统可靠性通用模型,进行可靠性分配及可靠性设计,用于水射流清洗设备生产设计、检验验收及质量评定等。最终完成具有燃烧爆炸风险防护,上坡、下坡及横向运输安全稳定,平均故障间隔时间tMTBF≥1000 h的水射流清洗设备研制。水射流清洗设备的安全可靠性分析与应用研究,可为今后易燃易爆环境撬装清洗设备的工程设计和施工作业提供一定参考。

1000kV特高压绝缘子运行特性研究方向

介绍了晋东南-南阳-荆门1000kV交流试验示范工程中线路用盘形悬式瓷、玻璃和复合绝缘子的使用情况。分析研究了特高压绝缘子运行的积污、电气、机械和劣化等性能方面的情况,认为:应加强对特高压绝缘子积污特性、绝缘子直径对雨闪特性的影响,串形对绝缘子的机械特性影响,绝缘子运行的可靠性和劣化特性及机械振动特性的研究。建议待建特高压工程支柱绝缘子采用双柱并列式或三角锥式;及时开展盘形悬式瓷绝缘子劣化率、复合绝缘子憎水性和机械特性及钢脚腐蚀检测等工作。为制订1000kV特高压绝缘子相关运行规程和待建特高压工程绝缘子优化选型奠定基础。

利用外场数据对产品工龄-可靠性特性的研究

本文采用了三参数相关系数优化法与图估法相结合的数据处理方法,利用外场数据,对某型航空发动机的工龄-可靠性特性进行了分析,得到相应的结论和对维修方式的建议。

Performance of Marine Power Plant Given Generator, Main and Distribution Switchboard Failures

Power generation is one of the most essential functions of any plant for continuous functioning without any interruption. A marine power plant （MPP） is the same section. In the present paper, the authors have tried to find the various reliability characteristics of an MPR A marine power plant which is a composition of two generators and in which one of them is located at the stern and another at the bow, both associated to the main switchboard （MSB）. The distribution switchboards （DSB） receive power from the MSB through cables and their respective junctions. Given that arrangement, a working based transition state diagram has been generated. With the help of the Markov process, a number of intro-differential equations are formed and solved by Laplace transform. Various reliability characteristics are calculated and discussed with the help of graphs.

Discussion on dynamic reliability tolerance design technology of electromagnetic relay

Reliability tolerance design of electromagnetic relay during its design period plays an essential role in guaranteeing the consistencies of reliability and output characteristic. The reliability tolerance design can ensure that the products would work well under the influence of disturbing factors (including internal interference, external interference, and machining dispersion). Com- pared with static characteristic, dynamic characteristic of electromagnetic relay can describe its operating process better. This article researches influence of the three kinds of disturbing factors on the dynamic characteristic of electromagnetic relay based on calculating dynamic characteristic. Then, the dynamic reliability tolerance design method of electromagnetic relay is discussed considering three kinds of disturbing factors. Conclusions reached can help to assure the reliability of electromagnetic relay from the beginning of design.

APPLICATION OF FUZZY LOGIC IN WEIGHTED INFORMATION FUSION OF HAND GEOMETRY AND PALM PRINTS

Based on the theory of fuzzy logic, the method of obfuscating coefficient and reliability to fuse the information of hand geometry and palm prints for identity discrimination is proposed. The experiment proves that the method is useful and effective. Its identification rate is up to 90%, which is 20%-30% higher than that of using hand geometry or palm prints singly,thus it can be widely used in highly demanded security field, such as finance, entrance guard, etc.

Reliability analysis of supporting pressure in tunnels based on three-dimensional failure mechanism

Based on nonlinear failure criterion,a three-dimensional failure mechanism of the possible collapse of deep tunnel is presented with limit analysis theory.Support pressure is taken into consideration in the virtual work equation performed under the upper bound theorem.It is necessary to point out that the properties of surrounding rock mass plays a vital role in the shape of collapsing rock mass.The first order reliability method and Monte Carlo simulation method are then employed to analyze the stability of presented mechanism.Different rock parameters are considered random variables to value the corresponding reliability index with an increasing applied support pressure.The reliability indexes calculated by two methods are in good agreement.Sensitivity analysis was performed and the influence of coefficient variation of rock parameters was discussed.It is shown that the tensile strength plays a much more important role in reliability index than dimensionless parameter,and that small changes occurring in the coefficient of variation would make great influence of reliability index.Thus,significant attention should be paid to the properties of surrounding rock mass and the applied support pressure to maintain the stability of tunnel can be determined for a given reliability index.

关于取消发动机翻修寿命的探讨

本文根据以可靠性为中心的维修思想,结合民航使用和维修JT3D发动机的情况进行分析,说明发动机定期翻修不符合发动机的可靠性特性,提出取消发动机翻修寿命,采用符合发动机可靠性特性的维修方式的一些看法。

Proposed Simplified Procedure for Safety Factor Scaling for Various Life Cycles

It is common to assume that structures are designed in view of 50 year life cycle as per Euro-Code 2 and other codes. In special cases, structures are designed in view of longer life cycle, such as bridges, important infrastructure facilities, important religious structures or in case of extended returning period of seismic event or floods. Beside issues of durability and maintenance aspects, this involves also the need to cover the probability of exceeding characteristic design live loads during the extended period, while keeping the same levels of the accepted risk that were assumed by the various codes, as good enough for the standard 50 year life cycle. Bearing in mind that design procedures, formulations, materials characteristic strengths and partial safety factors are used for these structures as per the existing codes, scaling of partial safety factors, or alternatively an additional ＂compensating＂ factor is required. A simplified approach and procedure to arrive at a reasonable calibration of the code safety factors based on 50 years to compensate for an extended life cycle, based upon structural reliability considerations, is proposed.

Analysis of Ground Motion Attenuation Characterization for Moderate Earthquakes in the Sichuan-Yunnan Region

The ground motion attenuation models for PGA,PGV and response spectrum at rock sites and soils sites are derived separately from the digital strong motion records of moderate earthquakes in the Sichuan-Yunnan region after 2007. By comparison with Yu Yanxiangs attenuation model for rock sites in western China,reliability of the model is verified for moderate earthquake. According to the distribution of strong motion data against magnitude and epicentral distance,the applicability and reliability of the results in this paper are discussed.

The Effects of Stochastic Characteristics of Materials on the Reliability of a Composite Ship Hull

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging.The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling,material failure,and ultimate collapse) were calculated by the surface response method and JC method.The importance factors of random variables in stochastic models,such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands,as well as the stochastic characteristics of materials in the models used,were calculated.Then,the effects of these random variables,including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging,were discussed with their importance factors.The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships.Finally,some conclusions and recommendations were given for high-speed ship design and safety assessment.

Dynamic Reliability Evaluation of Double-Layer Cylindrical Latticed Shell under Multi-Support Excitations

To overcome the excessive computational cost and/or bad accuracy of traditional approaches,the probabilistic density evolution method(PDEM) is introduced.The dynamic reliability of a double-layer cylindrical latticed shell is evaluated by applying PDEM and Monte Carlo Method(MCM) respectively,and four apparent wave velocities(100 m/s,500 m/s,800 m/s and 1 200 m/s) and five thresholds(0.1 m,0.2 m,0.3 m,0.4 m and 0.5 m) are taken into consideration.Only the difference between threshold and maximal deformation...

Study on slope reliability method Response Surface Method based on Morgenstern-Price Method

The combination of Morgenstern-Price Method （MPM） with Response Surface Method （RSM） improves the eonventional RSM by replacing Finite-Element Method （FEM） with MPM, which is a type of reliability analysis method-RSM based on MPM, and makes the computing process simpler. The stability of the slope was re-evaluated by use of Monte Carlo method （MCM） and the result contrasted with the fore is the conclusion. The reliability analysis of the artificial slope in Donggang Power Station was carried on, and obtained the reliable charaeteristics, which provided basis for the project.

MODELING AND SIMULATION OF COMPOUND CLUTTER FOR COASTAL ENVIRONMENT

This paper introduces a novel clutter power model of coastal compound and deduces the statistic characteristics and the arithmetics of model parameter estimation algorithm. Then, a novel coastal compound distributed model of the clutter amplitude is proposed and its statistic character- istics are studied. Subsequently, the nonlinear relation of autocorrelation function is deduced between the coastal compound clutter random sequences and the correlated Gaussian random sequences, which is the important prerequisite for the clutter simulation based on the ZMNL (Zero Memory NonLin- earity). Lastly, the advantage of the algorithm is demonstrated by a feasible simulation of the gen- eration of the random coastal compound clutter sequences.

Reduced Expanding Load Method for Simulation-Based Structural System Reliability Analysis

The current situation and difficulties of the structural system reliability analysis are mentioned. Then on the basis of Monte Carlo method and computer simulation, a new analysis method reduced expanding load method (RELM) is presented, which can be used to solve structural reliability problems effectively and conveniently. In this method, the uncertainties of loads, structural material properties and dimensions can be fully considered. If the statistic parameters of stochastic variables are known, by using this method, the probability of failure can be estimated rather accurately. In contrast with traditional approaches,RELM method gives a much better understanding of structural failure frequency and its reliability index β is more meaningful.To illustrate this new idea, a specific example is given.

Reliability analysis on bolt support structure of coal roadway under the influence of mining

Based on the features of the serious deformation of coal roadway,many random variables of the mechanics of the surrounding rocks and the influence of mining, the reliability analysis model of the support structure of coal roadway under the influence of mining is established,and the calculating formulas of reliability of the support structure is obtained with the engineering structure reliability theory. And the reliability is calculated based on the method of Monte Carlo to the coal roadway which is exampled on the influence of mining or not. The relationship between support parameters and reliability, the mining influence coefficients and reliability is established, which provides theory foundations for the design of the coal roadway bolt support.

Service-Oriented Middleware for Heterogeneous Environment in Intemet of Things

A great number of sensor technologies are applied in the Intemet of Things （loT） currently and more are emerging, which rmkes the loT a heterogeneous network. This paper discusses the convergence and integration problem in IoT. A Service-Oriented Middleware for Heterogeneous Environment （SOMHE） in IoT is proposed. The purpose of the middleware is to shield the differ- ence between protocols in the sensor layers such as Radio Frequency Identification （RFID） and Zig-Bee by defining the data conversion and mapping model. A Web service interface is supplied by this middleware, thus the complexity of high level appli-cation development can be reduced greatly. The feasibility and reliability of this middleware is veri-fied by a demonstration systelTL

A posteriori error estimator for eigenvalue problems by mixed finite element method

In this paper,a residual type of a posteriori error estimator for the general second order elliptic eigenpair approximation by the mixed finite element method is derived and analyzed,based on a type of superconvergence result of the eigenfunction approximation.Its efficiency and reliability are proved by both theoretical analysis and numerical experiments.