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常见失效形式 模具失效是指模具工作部分发生严重磨损或损坏而不能用一般修复方法(刃磨、抛光)使其重新服役的现象。模具的失效有达到预定寿命的正常失效(也叫工作失效),也有远低干预定寿命的早期失效(也叫偶然失效)。正常失效是比较安全的,而早期失效则带来经济损失,甚至可能造成人身或设备事故,应尽量避免。 相似文献
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传统抽油杆柱可靠性分析常采用"正常"和"失效"两级突变模式,未考虑到工程实际中的中介状态,在分析抽油杆失效故障树的基础上,提出基于"安全-中介-失效"三级工作模式的抽油杆可靠性分析。采用随机事件的S并运算和T交运算规则,建立具有中介状态抽油杆柱失效故障树可靠性向量的计算方法,求出抽油杆工作期间处于各种工作状态的概率,即安全概率,中介概率和失效概率,算例表明分析结果更加符合实际情况。 相似文献
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文中针对卡口式流体连接器在超过最大工作流量下使用过程中出现密封失效的问题,从理论上进行了产品失效的机理分析。通过耐流量冲击试验,得出卡口式流体连接器的失效流量值和失效模式。试验得出的失效流量值均大于按规定流速5 m/s 计算得出的最大工作流量,验证了卡口式流体连接器规定的最大工作流量是安全可靠的。同时,通过数值模拟和试验的对比分析,得出卡口式流体连接器在失效流量下产生的较大压力差和最大流速主要集中在插头内部密封块上的O形圈处和插座内部密封杆上的O形圈处,与失效模式相符。该研究结果表明,可以通过数值模拟预测卡口式流体连接器内部O形圈脱出的失效模式。 相似文献
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论述了机电装备失效分析预测预防的地位和作用,分析了我国机电装备失效分析预测预防工作的现状和进展,并提出了我国机电装备失效分析预测预防工作的建议。 相似文献
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介绍了采煤机行走机构的研究现状,分析了其结构组成,针对行走机构时常发生部件失效现象,开展了齿轨轮与销排主要部件的失效分析研究,找到了齿轨轮与销排的失效原因,得出了"企业在实际工作过程中,需加强对行走机构的日常维护和定期维修,合理改善井下工作环境,降低结构失效概率"的结论,以期为企业找到采煤机发生失效原因提供理论参考。 相似文献
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介绍了弹簧操动机构拒合故障的一般种类和排除方法,叙述了一例罕见的弹簧操动机构拒合故障的排除过程。 相似文献
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针对小直径石英压力计高温失效的具体情况,采取对已失效的压力计解剖分析的方法,研究压力计高温失效的机理及主要影响因素,提出对压力计关键部件结构改进措施和装配工艺改进措施。在实施改进措施后,压力计高温失效的问题得到解决。目前,该仪器已在油田现场测试中推广使用,取得良好效果。 相似文献
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H. Czichos 《Wear》1974,28(1):95-101
The mechanisms of film failure of lubricated concentrated contacts are discussed in relation to critical failure data of operating variables, calculations of scoring surface temperatures and scanning electron photomicrographs of worn contact zone topographies. Depending on the critical values of operating variables failure modes in the form of local break through of EHD oil film at the outlet end of the contact zone as well as gross thermal desorption effects were found. 相似文献
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Time-dependent vibration frequency reliability analysis of blade vibration of compressor wheel of turbocharger for vehicle application 总被引:1,自引:0,他引:1
Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently. 相似文献
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在许多重要的工作系统中,备用设备是用来防止重大事故的安全保护设备,除了运行故障外,启动故障也是影响这类应急备用设备可靠性的主要因素。本文提出院一种同时考虑启动故障与运行故障后备用设备的可靠性评估方法,并建立了相应的评估概率模型。实例计算分析表明,该方法具有较好的工程实用意义。 相似文献
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Hamid Reza Golmakani Hamid Moakedi 《The International Journal of Advanced Manufacturing Technology》2012,61(1-4):295-302
This paper proposes a model to find optimal periodic inspection interval for a multi-component repairable system with failure interaction. Failure of one component of the system is hard, i.e., as soon as it occurs, the system stops operating. Failures of the other components are soft, namely, they do not cause the system stop. Soft failures increase the system operating costs and are detected only if inspection is performed. Thus, the components with soft failure are periodically inspected simultaneously and are repaired if found failed. When the component with hard failure fails, it is also repaired. However, it increases the failure rate of the other components. The objective is to find the optimal inspection interval such that, on a finite time horizon, the expected total cost is minimized. The proposed modeling approach is illustrated through a simplified numerical example for a general infusion pump. 相似文献