Risk-based inspection (RBI) of a gas pressure reduction station

One of the principles of corrosion management is proper inspection methodology, and in particular the risk-based inspection (RBI). Occasionally a large percentage of the total risk of a unit is concentrated in a small part of the equipment, which can be reduced by using risk management techniques. In this study, a semi-quantitative risk-based inspection method has been performed in a gas station with for its components (pipelines, filters, etc.), to identify the existing damage mechanisms and also to rank its equipment in terms of inspection intervals. In this regard, RBI was performed for the gas station which consisted of phases (Phase A & Phase B) with Class 300 and Class 600 equipment. According to documented conditions and reviewed records the main damage mechanism for the investigated components in the gas station was identified as wall thinning due to erosion corrosion and external corrosion. In terms of inspection, results showed that most of the equipment studied had medium risk level and a few had medium to high level of risk. In this regard, the corrosion rates of Class 300 and Class 600 equipment were also studied and compared, and it was indicated that the corrosion rates were higher at locations for Class 300 equipment where more pressure drop had occurred. Overall, based on the obtained corrosion rates and obtained risk matrixes, it was concluded that wall thinning (erosion-corrosion) was the determining risk factor for equipment inspected in the gas pressure reduction station.     

某型液体发动机高空环境局部失效和改进分析

通过对某型液体发动机高空环境下局部产品失效问题进行分析,得出了产品失效原因和形成过程。按照不同的需求,针对性地提出了改进措施,提高了发动机高空环境下工作的可靠性和环境适应性,通过实际飞行试验予以验证。     

电子部件失效模式试验与仿真研究

目的研究焊点在热应力下的等效应力和等效蠕性应变。方法通过测定某子弹电子部件的工作极限温度、破坏极限温度,利用阶梯变化的温度来验证电子部件的极限适应温度,找出电子部件的主要失效模式。通过有限元仿真来模拟热载荷作用下焊点的应力应变行为。结果应用Garofalo模型仿真得出的蠕变效应与实际试验结果基本相近。结论通过仿真方法与试验结果相对比,证明使用Garofalo模型来研究电子部件焊点的蠕变效应是可行的。     

环氧富锌-石墨烯涂层在中性盐雾和高低温循环浸泡中的失效研究

目的 研究20#钢表面环氧富锌-石墨烯涂层在中性盐雾和高低温循环浸泡(3.5％NaCl溶液,45℃12 h+RT 12 h)试验中的失效过程与行为.方法 采用电化学交流阻抗(EIS)测试、开路电位(OCP)监测、扫描电镜观察与分析(SEM/EDS)以及红外光谱(FTIR)等方法研究涂层在两种试验环境中的失效特征和对20#钢的保护作用,并探讨涂层失效的低频阻抗评价标准.结果 涂层试样分别在中性盐雾79 d和高低温循环浸泡160 d后,表面开始出现锈点,失去对基体的保护作用,此时低频阻抗(|Z|0.01 Hz)值降至7×104?·cm2左右.除了屏蔽作用以外,环氧富锌-石墨烯涂层还可为钢基体提供一定的阴极保护作用,其中高低温浸泡环境中的阴极保护作用时间略长.在两种加速试验环境中,涂层后期的失光率均处于"明显失光",色差值达到或接近"较大变色".红外光谱显示,涂层中的特征官能团未发生明显的变化.结论 通常利用低频阻抗(|Z|0.01 Hz)低于1×106?·cm2来衡量有机涂层(不含导电颗粒)失效的判据,不适用于评价碳钢表面的环氧富锌-石墨烯涂层体系,对于该体系的失效评价可能需要再降低近2个数量级,约为7×104?·cm2左右.     

某型滑油温度传感器的可靠性强化试验

针对诱发滑油温度传感器故障模式的主要环境因素进行了分析,确定了影响滑油温度传感器可靠性的敏感环境应力。根据滑油温度传感器结构间的逻辑关系和可靠性框图,建立其故障树,找出了潜在薄弱环节作为可靠性强化试验的主要关注点。依据可靠性强化试验理论设计了试验方案,并制定了试验剖面。     

压缩和劈裂荷载作用下岩石最大伸长应变差异的试验研究

从力学机制上看,岩石破坏可分为剪切破坏和拉伸破坏两种基本形式,它们各自都有不同的破坏准则,其中最大正应变强度准则是一个应用相对比较简单的岩石破坏准则。最大正应变强度准则判据建立的关键是如何标定极限伸长应变Σ_0。岩石在压应力和拉应力作用下都有可能发生符合最大(伸长)正应变准则的破坏。根据弹性理论,岩石在受拉和受压时对应的最大正应变临界值是等价的。然而,由于岩石材料的复杂性,岩石实际受压与受拉导致最大正应变形式的破坏所对应的最大正应变会有较大的差别。通过试验,本文揭示了不同种类的岩石在受拉、受压破坏时最大伸长应变的差异以及受压和受拉条件下岩石最大拉伸应变的理论值和试验值之间的差异。     

战略环境评价研究与实践进展

回顾了战略环境评价的起源，发展历程，尤其是９０年代以来的实践与研究成果；分析了当前研究趋势并提出了今后我国战略环境评价工作的重点，包括加强研究，建立保证体系和进行试点等。     

气田输水管道失效浅析及对策

随着气田开发至中晚期,气田水量不断增大,若不能及时有效处理将严重制约气田的开发,目前气田水处理普遍采取汽车和管道两种方式运输至回注站回注。文章通过对气田水运输中管道失效的表现形式、失效原因进行分析,提出管道失效的解决办法及对策,以确保气田水输送管道长效、稳定运行和气田水的正常运输,保障气田的有序开发。     

Occupational Cognitive Failure and Its Relationship With Unsafe Behaviors and Accidents

Objectives. The aim of this study was to assess the relationship between occupational cognitive failures (OCFs) and unsafe behaviors, accidents and driving offences among municipal bus drivers in Tehran, Iran. Methods. Systematic random sampling was used to select 190 drivers from 3 transport and traffic Tehran districts. Data were collected with the occupational cognitive failure questionnaire (OCFQ), the driver behavior questionnaire and a data collection form. Results. The mean (SD) numbers of driving-related offences and road traffic accidents were 1.5 (2.6) and 0.37 (1.0), respectively. The mean (SD) numbers of deliberate driving violations, unintended violations, driving slips and mistakes were 6.97 (5.5), 1.61 (1.5), 13.6 (9.0) and 4.53 (3.28), respectively. The mean (SD) number of the OCFs was 28.9 (20.5). A significant correlation was found between occupational cognitive error and unsafe driving behavior subscales. The stepwise logistic regression results showed that, while controlling the effects of confounding factors, the OCF predicts 6%, 9%, 15% and 9% of deliberate violations, unintended violations, driving slips and driving mistakes, respectively. Conclusion. The results of this study show that the score of the OCFQ is a predictor of unsafe driving behaviors and its subscales.     

大规模采空区渐进式矿柱坍塌的简化模拟

空场法开采的矿山,往往留下大面积的采空区,易发生渐进式倒塌的整体性破坏.针对大量不规则点柱支撑顶板的复杂采空区结构,采用Voronoi图形划分方法确定顶板荷载面积,在此基础上提出了模拟矿柱破坏、荷载转移、应力重新分布过程的计算方法及其适用性.以浙江长兴白象硅灰石矿采空区结构为案例,进行了计算验证,圈定了潜在的采空塌陷区范围,并从理论上提出了控制采空区大面积塌陷的对策.该方法对于该类型矿山的采空区地压控制具有指导意义.