GO法进行有共因失效系统可靠性分析的新算法研究

共因失效可能使系统的可靠性大大降低,是系统可靠性分析中的重点和难点。GO法可以对含共因失效的系统进行可靠性分析。为了选取已有算法合适的参数,更为了提高有多个共因失效组系统的GO法可靠性分析效率,进行了相关研究。对关键参数公式进行了理论分析,并就几个算例系统进行了计算试验;对已有算法进行了深入研究,为了改进已有算法对共因失效组逐个处理,提出了将共因失效组中的部件均由本组等效共因失效部件代替的新算法。进而,应用分组法和新算法对一个简单示例系统和外电源备用系统进行了共因失效分析。给出了对已有算法参数选取的建议;通过对比可知分组法与新算法计算结果相近。通过对已有算法参数的合理化选取,可以提高计算结果的准确度;新算法可对所有共因失效组一次性处理,是共因失效分析的有效方法。     

Thermal risk in batch reactors: Case of peracetic acid synthesis

The present paper deals with accidents risk in batch reactors. It identifies the conditions for the occurrence of a thermal runaway and develops a probabilistic approach to assess the relevant risk. It investigates also the conditions for optimal synthesis of peracetic acid (PAA) with hydrogen peroxide (HP) and acetic acid (AA). The kinetic model of reversible reaction and side reaction of PAA synthesis is used to predict reactor temperature and molar ratio of PAA by ASPEN PLUS software. A sensitivity analysis is performed under different conditions such as constant temperature or adiabatic process with different concentrations of sulfuric acid. Assuming a prior cooling system failure, the conditions for reaction runaway triggering a thermal accident are identified in the case of PAA synthesis. Monte Carlo simulations are used in order to calculate the conditional probability of accident and optimize the synthesis of PAA.     

History of Dutch process equipment failure frequencies and the Purple Book

In the middle of 70s concerns of the public in the Netherlands about fire, explosion and toxic risks due to mishaps in the expanding process industry, causing political pressure led to the embracement of quantitative risk analysis as tool for licensing and land-use planning. Probabilistic treatment of risk had been exercised before to design flood defense. A ‘test’ on six different plants, the COVO study, favored the idea. Failure rate values were in immediate need. For storage vessels AKZO’s chlorine vessel data and British steam boiler data have been the first. Risk criteria to make decisions on were also developed and in 1985 embodied in legislation. As licensing and land-use planning are tasks of provincial authorities, under the auspices of the Inter-Provincial Consultation (IPO), further details such as failure frequency values have been worked out. In the late 90s the Purple Book consolidated the information as a guideline for Dutch quantitative risk assessment of process installations.The paper will give a condensed historical overview, guidance to published papers; it will further make comments, explain policy backgrounds, present comparison with other data and will briefly indicate in which direction developments should go to improve QRA.     

爆炸荷载作用下方钢管混凝土柱的动力响应及破坏机理

方钢管混凝土柱是被广泛采用的组合构件之一.爆炸发生时产生的爆炸冲击波可能会对框架结构内部的方钢管混凝土拄造成严重破坏,然而目前对其动力响应及破坏机理的研究成果相对较少.本文采用有限元分析软件ANSYS/LS-DYNA对爆炸荷载作用下方钢管混凝土柱的动力响应和破坏机理进行了研究分析.建立了方钢管混凝土拄实体有限元模型,其...     

基于Monte-Carlo随机有限元的火灾可靠性研究--以混凝土简支梁为例

通过对建筑火灾的背景分析和研究现状的回顾,指出了进行建筑火灾可靠性研究的必要性.介绍了蒙特卡罗随机有限元计算的基本原理、随机数的产生办法和模拟次数的确定,最后作者采用通用有限元程序ANSYS计算了混凝土简支梁在不同温度、保护层厚度和荷载下的火灾可靠性.     

航空机载电子设备早期故障实例分析

通过在试验中发现产品的早期故障进行分析研究,提出改进设计和工艺措施,根除早期故障产生的原因,以提高我国航空机载电子设备的可靠性水平。     

旋转电极式电除尘器清灰刷寿命实验方法设计

旋转电极式电除尘器可有效解决电除尘器振打造成的二次扬尘问题,降低出口粉尘排放浓度,是目前新建和改造电除尘器采用的主流技术之一,尤其对于改造项目具有非常好的经济性。清灰刷作为旋转电极式电除尘器的关键部件之一,其失效形式和使用寿命的研究非常重要。通过分析实验原理,设计了清灰刷失效形式和寿命的实验方法,搭建了实验装置,设计了清灰刷的测量和评价方法,对清灰刷的压力、倒伏等性能进行了测试工具设计,观察了清灰刷的显微结构,对国内某厂家的清灰刷做了初步实验并得到初步的结论,为清灰刷的进一步实验和改进提供了基础。     

重力流排水管道内流态对生物膜菌落结构的影响

为探究排水管内壁面剪切力与生物菌落结构之间的关系,基于排水管道内流态与壁面剪切应力二维回归模型,建立了3套管道生物膜培养装置,利用微电级技术获得了3种不同剪切力条件下生物膜厚度随时间变化规律,结果显示：剪切力分别为1.12、1.29和1.45 Pa时,对应生物膜稳定厚度分别为（2.40±0.15）、（2.70±0.15）和（2.20±0.15）mm。结合高通量测试技术与溶解氧微电级技术研究了不同壁面剪切力对生物膜菌落结构的影响,得出F=1.29 Pa为异养菌最适生长的剪切力,有利于COD的去除,COD去除率达到40.13%。     

基于热-结构耦合分析的液化石油气储罐失效预警判定

为研究火灾中球罐应力场分布情况,找到球罐失效破裂条件,以液化石油气为研究对象,基于球罐稳态热响应,通过ANSYS热-结构耦合有限元分析法进行研究.结果表明:充装率85％的液化石油气球罐最高温度部位出现在气相区,约619.66℃;最大应力值出现在气液交界处,约615.18 MPa;得到球罐破裂失效时温度值和应力值,并设置...