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1.
针对目前国内缺乏输气站场风险因素客观失效概率的问题,提出采用模糊失效概率来确定输气站场风险因素的失效概率。该方法以专家判断为基础,采用模糊集理论将专家判断结果转化为模糊失效概率。以人员受伤面积作为失效后果评价指标,从而计算出风险值,并提出风险等级划分方法。最后对达化输气站收球区进行风险评价,其评价结果与实际风险程度一致。  相似文献   

2.
本文介绍了一种将计算机仿真应用于延长建筑物使用寿命的方法.由于建筑物有其设计基准期.即设计的使用时间.建筑物的使用寿命如已到达设计基准期.并不意味着这个建筑物就立即不能用.而只是其失效概率将比预计值要大.如延长使用时间,即超过设计基准期.将会带来一定风险.因此.风险分析在延长建筑物使用寿命时是十分重要的.  相似文献   

3.
针对肯特法中评价指标分值累加会隐藏指标低分值情况的不足,采用将指标分值转化为失效概率的方法对肯特管道风险评价算法进行改进。首先将评价指标得分值划分为5个区间,每个区间对应相应的失效可能性等级;然后将失效可能性等级转化为模糊数,再将模糊数转化为指标的失效概率;最后将所有指标的失效概率进行相加得到管道失效总概率,从而计算出风险值。通过实例计算表明,肯特管道风险评价改进算法更能反映管道的实际风险情况。  相似文献   

4.
运用故障树分析法、FMEA分析方法,对往复式压缩机的各子系统进行失效模式影响分析。通过对某大型石化企业1993~2013年往复式压缩机3 322条运行和维修数据进行分析研究,得出了其中各关键零部件及各失效模式的失效概率及失效后果。利用K-S检验法及威布尔模型对往复式压缩机组的大修间隔时间进行分析,确定出该组压缩机的平均无故障时间为1.92年,稳态可用度为0.997。  相似文献   

5.
针对半定量与定量风险评价方法的优缺点,提出指标概率综合风险评价新方法(简称I-P法)。该方法不仅能够克服半定量评价法容易产生"避重就轻"现象的弊端,又能克服定量评价法中因缺失指标失效概率而无法应用的不足。I-P法下层指标采用基于专家经验的指标评价方法,而后利用BP神经网络方法建立指标相对分值d与失效概率Pf(i)的关系曲线,依据此曲线将指标分值转化为失效概率,并对上层指标采用基于失效概率的定量评价。采用该方法对某管道的河沟道水毁进行了风险评价,结果表明,该方法能够解决在某些特殊条件下基于指标评价法的结论与管道实际风险状态不一致的问题。  相似文献   

6.
油气长输管道外腐蚀维护风险缓解程度模型   总被引:7,自引:0,他引:7  
对危害油气长输管道安全性的因数进行分析,通过故障树分析法,找出了导致管道外腐蚀穿孔破坏的31种影响因素,确定了各影响因素的逻辑关系,建立了故障树最小割集.通过专家主观评判对各基本事件的失效情况进行分析,将专家自然语言通过模糊数学的方法转换为模糊数,然后采用左右模糊排序法将[0,1]区间的模糊数转换位模糊失效概率值.针对危害管道的失效因素,采取现行比较常用的外腐蚀管道维护方法和对基本事件进行安全整改,然后聘请专家对管道维护前后的情况进行评判,采用所建立的计算基本事件失效概率值方法和所建立的最小割集,计算出外腐蚀管道维护前后失效概率,表明采取有针对性的维修和维护措施,管道的失效概率将会明显减低,降低了该管段的风险值.  相似文献   

7.
对汽车发动机装配风险进行积极的识别和预防管理,对保障汽车质量、提升汽车制造企业效益、降低汽车制造成本等具有十分积极的意义。基于过程失效模式及后果分析(PFMEA)方法,提出发动机装配风险探测、识别与降解策略,预防风险发生。识别发动机装配过程的关键工序,分析失效影响(FE)、失效模式(FM)和失效起因(FC),对S(严重度)、O(频度)、D(可探测度)进行打分,通过优先级(AP)矩阵识别出高风险点。针对高风险项目,改善发动机装配线布置,提出高风险预防方法和路径。优化改进后,低风险项目占比由21%提高至43%,有效降解了发动机装配风险。  相似文献   

8.
五、与状态维修有关的问题在监测系统用于一般用途之前 ,或者在设备上有选择地安装新监测系统之前 ,必须考虑功能需求和结构需求的问题和实施监测的一些条件。1 监测工作应具备的功能要想对所有可能影响设备劣化和失效进行监测 ,必须区别下列各种情况 :①在线监测能够检测的劣化 ;②正常监测无法检测的劣化 ,但能用无损检测 (例如超声波检测 )查明 ;③只能通过干扰性检查方法才能鉴别和量化的所谓潜在劣化。监测工作的功能很重要 ,要具有下列几种功能 :预防主要风险 ;优化维修工作 ;有助于设备运行。(1)预防主要风险预防主要设备发生失效和…  相似文献   

9.
薛建 《化工管理》2022,(12):71-73
针对海洋石油重点设备设施结构存在的安全风险和失效形式,传统的检测手段存在的弊端越来越明显,给设备设施的安全运行埋下隐患。为提升海洋石油设备设施结构检测水平、提高检测效率、减少设备设施停机时间、降低生产作业成本、及早发现并准确掌握设备设施结构的变形、微裂纹、应力集中等情况,提出采用光纤光栅传感监测技术用于海洋石油重点设备设施结构关键区域的应力监测,实现结构失效的早期预警。  相似文献   

10.
设备的可靠性除了设计、制造等方面的因素外,还取决于设备的管理与维修。预防性维修是现代企业普遍采用的一种维修方法,是消除设备失效和计划外停机的有效措施,同时可以提高生产效率。  相似文献   

11.
This paper addresses problems associated with production control and occupational safety in a manufacturing system prone to failure involving two machines working in passive redundancy. Machines turning out one part experience two modes of failure and repair: firstly, where failure occurs when a machine remains in fair condition; and, secondly, where such failure results in outright breakdown. Accordingly, we examine both modes of failure for their impact on a flexible manufacturing system (FMS) with respect to production control in terms of costs associated with lockout/tagout procedures and corrective maintenance. This study seeks to identify optimal costs related to backlogs, inventories and maintenance over an infinite planning horizon, along with levels of occupational risk where production control includes efficient planning of lockouts/tagouts. Our study offers numerical methods which may be employed to achieve optimal conditions in setting control policies. A numerical example and sensitivity analysis support this approach.  相似文献   

12.
针对传统故障分析方法缺乏系统性的问题,以多状态退化系统为研究对象,引入风险优先数(RPN),借助多粒度语言评价集结系统,提出了一种新的多状态退化过程的评估方法。明晰了系统退化过程的关键环节和关键参量,更加全面地分析故障演变过程。以系统风险加权后的最低维修费用为目标,运用策略迭代算法,计算出不同故障状态下的最优维修策略。以算例说明故障分析过程,验证了所提方法的有效性和实用性。  相似文献   

13.
This paper deals with the problem of integrating noncyclical preventive maintenance and tactical production planning for a single machine. We are given a set of products that must be produced in lots during a specified finite planning horizon. The maintenance policy suggests possible preventive replacements at the beginning of each production planning period, and minimal repair at machine failure. The proposed model determines simultaneously the optimal production plan and the instants of preventive maintenance actions. The objective is to minimize the sum of preventive and corrective maintenance costs, setup costs, holding costs, backorder costs and production costs, while satisfying the demand for all products over the entire horizon. The problem is solved by comparing the results of several multi-product capacitated lot-sizing problems. The value of the integration and that of using noncyclical preventive maintenance when the demand varies from one period to another are illustrated through a numerical example and validated by a design of experiment. The later has shown that the integration of maintenance and production planning can reduce the total maintenance and production cost and the removal of periodicity constraint is directly affected by the demand fluctuation and can also reduce the total maintenance and production cost.  相似文献   

14.
基于价值工程的建筑节能方案优选研究   总被引:2,自引:1,他引:1  
随着能源危机的日益凸显,建筑节能已经提上日程。如何在成本控制的范围内,选用合适的建筑节能材料和建筑节能技术变得越来越重要。这就要求对各种建筑节能方案进行比选,从而找出经济效益、环境效益和社会效益最优的方案。文章将从建筑节能方案的综合效益出发,构建一套建筑节能方案综合评价指标体系,运用层次分析法赋予不同权重,进行方案的功能评价,再引入价值工程的方法,从全寿命周期角度进行建筑节能方案的优选。  相似文献   

15.
This paper presents a method to find the optimal production, repair/replacement and preventive maintenance policies for a degraded manufacturing system. The system is subject to random machine failures and repairs. The status of the system is deemed to degrade with repair activities. When a failure occurs, the machine is either repaired or replaced, and a replacement action renews the machine, while a repair action brings it to a degraded operational state, with the next repair time increasing as the number of repairs increases as well. A preventive maintenance action is considered in order to improve the reliability of the machine, thereby reducing the amount of disruptions caused by machine failures. The decision variables are the production rate, the preventive maintenance rate and the repair/replacement switching policy upon machine failure. The objective of the study is to find the decision variables that minimize the overall cost, including repair, replacement, preventive maintenance, inventory holding and backlog costs over an infinite planning horizon. The proposed model is based on a semi-Markov decision process, and the stochastic dynamic programming method is used to obtain the optimality conditions. A numerical example is given to illustrate the proposed model, and a sensitivity analysis is considered in order to confirm the structure of the control policy and to illustrate the usefulness of the proposed approach.  相似文献   

16.
Reverse Mortgages and Borrower Maintenance Risk   总被引:1,自引:0,他引:1  
This paper develops a theoretical model of the problem of maintenance risk in reverse mortgages (RMs) and home equity conversion instruments generally. By maintenance risk, we refer to the incentive homeowners will have to reduce maintenance expenditures as their equity in the house falls during the term of the RM. The underlying reason for this tendency is the limited liability feature of RMs, given that a borrower's obligation to the lender at. maturity is limited to the value of the house.
The results of the model show that lenders will respond to this problem either by limiting the amount of RM loans to guarantee that maintenance risk is not a threat, or by charging an interest rate premium to cover the expected cost of default. Unfortunately, there do not exist data to test the importance of maintenance risk as a possible limitation on the extent of the RM market.  相似文献   

17.
Heterogeneity in component and maintenance quality is considered in the context of age-based inspection and replacement for a single component system. A three-state component failure model is assumed, with a defective state preceding the failed state. Heterogeneity in maintenance intervention is modelled by supposing that inspections may induce the defective state. Component heterogeneity is modelled by supposing that the population of components comprises a mixture of the weak and strong, and that the mixing proportion and cost of components vary between suppliers. Within this framework, the impact, on system reliability and cost, of switching component or maintenance supplier is determined. Broadly, our finding is that one is much more inclined to switch supplier in order to obtain higher quality maintenance than to obtain higher quality components. A gas pressure control valve is used to illustrate our ideas.  相似文献   

18.
The purpose of this article is to develop a practical economic replacement decision model to identify the economic lifetime of a mining drilling machine. A data-driven optimization model was developed for operating and maintenance costs, purchase price, and machine resale value. Equivalent present value of these costs by using discount rate was considered. The proposed model shows that the absolute optimal replacement time (ORT) of a drilling machine used in one underground mine in Sweden is 115 months. Sensitivity and regression analysis show that the maintenance cost has the largest impact on the ORT of this machine. The proposed decision-making model is applicable and useful and can be implemented within the mining industry.  相似文献   

19.
This paper presents the effects of a free-repair warranty on a periodic replacement policy with a discrete time process. Considering a repairable product that should be operational at the time over an indefinitely long operation cycle n (n=1, 2, …), under the discrete-time periodic replacement policy, a product is preventively replaced at pre-specified operation cycles N, 2N, 3N, … (N=1, 2, …). When the product fails, a minimal repair is performed at the time of failure, and the failure rate is not disturbed by each repair. The cost models from the customers' perspectives are developed for both warranted and non-warranted products. The corresponding optimal replacement period N? is derived such that the long-run expected cost rate is minimized. Under the assumption of the discrete time increasing failure rate, the existence and uniqueness of the optimal replacement period are shown, and the impact of a free-repair warranty on the optimal periodic replacement policies is investigated analytically. The optimal N* for a warranted product should be adjusted toward the end of the warranty period. Finally, numerical examples are demonstrated for the optimal policy illustration and verification. The observations from the numerical results provide valuable information for a buyer (user) to adjust the optimal periodic replacement policy if a product is operating in discrete time under a free-repair warranty.  相似文献   

20.
The economic life (EL) method of asset replacement is analyzed under improving technology that impacts the maintenance cost, new asset cost, and salvage value. In particular, we prove that the asset EL is constant when all these costs decrease with the same rate. If these costs decrease geometrically, then the EL method with a corrected capital recovery factor calculates the optimal asset lifetime over the infinite horizon for arbitrary age-dependent deterioration and salvage value. In a general case, the EL method delivers an optimal replacement decision when the relative rate of technological change is less than 1%. For larger rates, we recommend to minimize the annual cost over two future replacement cycles, which was earlier proposed and implemented by Christer and Scarf, Journal of the Operational Research Society 45, 1994.  相似文献   

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