Reliability analysis techniques for mechanical systems

This paper discusses the application of known system reliability analysis techniques and identifies problems encountered in the practical implementation of these methods, revealing that no single technique is sufficient or even feasible in the case of complex mechanical systems. A new functional analysis method as well as a (new) criticality quantitative approach and failure mechanism analysis are presented and used to analyse an aircraft fuel system. A rigorous and detailed FMECA is still required. Besides its main function it will supply much of the valuable information for many other techniques.     

The use of computer-aided engineering in reliability studies

This paper discusses how computer-aided engineering can be extended beyond the use of design verification into the area of dynamic failure effects analysis for both digital and analogue electronic circuits as well as complete systems encompassing any engineering discipline.     

FMECA在雷达装备综合保障中的开展与应用

综合保障是提高装备战斗力的重要手段，综合保障工作的开展，可以全面解决装备可靠性、维修性、测试性、安全性和保障性的问题。而在装备综合保障工作中，可以通过开展FMECA来获得可靠性、维修性、测试性、安全性和保障性的重要信息，从而指导装备综合保障各项工作的开展，发现综合保障中的薄弱环节，从而提出改进措施。该文重点讨论FMECA在综合保障各项工作中的重要意义，并为FMECA适应综合保障工作提出了相应的要求及实现方法，使FMECA成为综合保障的核心工作内容。在某型雷达综合保障工作中，通过重点开展FMECA工作达到综合保障设计的要求。     

基于多层次信息融合的水轮机调速器故障诊断

在建立故障诊断的信息模型基础上,设计了一种软件传感器,用于帮助在故障诊断中提供不能直接测量的重要性能信息,通过融合不同层次的信息提取动态过程的特征参数,然后用作FMECA故障诊断模型的输入,进行故障识别.应用该方法进行水轮机调速器故障诊断,能给出引起故障发生原因的各种组合和概率.实际应用表明,该方法的快速性能满足水轮机调速器在线故障诊断辅助决策的要求.     

基于产品族的复杂装备FMECA 方法及应用

针对当前复杂装备故障模式影响及危害性分析（FMEA/FME-CA）工作难以实施及低效率的问题,提出了基于产品族的FMECA方法。同时,应用模糊集和证据理论,给出了考虑复杂装备研制早期 RMS属性值模糊、不确定和非量化等特性的产品族聚类算法,给出了基于产品族进行 FMECA 的分析过程以及支撑本方法有效应用的产品平台故障信息库构建方法。最后,通过实例分析及与常规FMECA结果对比,验证了本方法的可行性和有效性。     

基于改进危害度和DEMATEL方法的abc轴进给系统的故障排序

基于某型号加工中心的abc轴进给系统的故障数据,首先进行故障模式、影响及危害性分析(FMECA),然后使用群体决策理论合理地整合团队成员的评估值,采用熵权和专家评估结合方法确定各因素权重,进而计算出abc轴进给系统各个故障的改进危害度(ICR)。根据以ICR为输入数据的决策与试验评价实验室(DEMATEL)方法排列故障优先处理顺序。将最终排序结果与传统危害度排序结果以及改进危害度排序结果进行比较,得到abc轴进给系统的薄弱环节。本文方法也可以用于整机的故障分析和排序,进一步为加工中心可靠性设计和可靠性提高奠定了基础。     

考虑相关性的数控车床多因素可靠性分配法

以数控车床为研究对象,针对基于子系统间失效独立假设分配模型的不足,提出一种考虑子系统故障相关性的多因素可靠性分配方法.应用Copula理论进行故障相关性分析,建立整机可靠度函数.根据数控车床故障模式、影响及危害性分析(FMECA),对传统危害度计算公式进行修正.考虑多种分配因素建立分配矩阵,得到分配向量.将分配向量与整机可靠度函数模型将结合,得到各子系统失效率分配值.将分配方法应用到具体实例中,并将考虑不同子系统故障相关性情况的结果进行分析对比.结果表明,提出的可靠性分配方法相对于基于独立假设的分配法能够分配给各子系统更高的失效率,在降低数控车床子系统设计制造成本上具有重要意义.     

System failure analysis based on DEMATEL–ISM and FMECA

A new method of system failure analysis was proposed. First, considering the relationships between the failure subsystems,the decision making trial and evaluation laboratory（DEMATEL） method was used to calculate the degree of correlation between the failure subsystems, analyze the combined effect of related failures, and obtain the degree of correlation by using the directed graph and matrix operations. Then, the interpretative structural modeling（ISM） method was combined to intuitively show the logical relationship of many failure subsystems and their influences on each other by using multilevel hierarchical structure model and obtaining the critical subsystems. Finally, failure mode effects and criticality analysis（FMECA） was used to perform a qualitative hazard analysis of critical subsystems, determine the critical failure mode, and clarify the direction of reliability improvement.Through an example, the result demonstrates that the proposed method can be efficiently applied to system failure analysis problems.     

Weakness Ranking Method for Subsystems of Heavy-Duty Machine Tools Based on FMECA Information

Heavy-duty machine tools are composed of many subsystems with different functions,and their reliability is gov-erned by the reliabilities of these subsystems.It is important to rank the weaknesses of subsystems and identify the weakest subsystem to optimize products and improve their reliabilities.However,traditional ranking methods based on failure mode effect and critical analysis(FMECA)does not consider the complex maintenance of products.Herein,a weakness ranking method for the subsystems of heavy-duty machine tools is proposed based on general-ized FMECA information.In this method,eight reliability indexes,including maintainability and maintenance cost,are considered in the generalized FMECA information.Subsequently,the cognition best worst method is used to calculate the weight of each screened index,and the weaknesses of the subsystems are ranked using a technique for order preference by similarity to an ideal solution.Finally,based on the failure data collected from certain domestic heavy-duty horizontal lathes,the weakness ranking result of the subsystems is obtained to verify the effectiveness of the proposed method.An improved weakness ranking method that can comprehensively analyze and identify weak subsystems is proposed herein for designing and improving the reliability of complex electromechanical products.     

A computer‐aided methodology to design safe food packaging and related systems

A specific “Failure Mode, Effects, and Criticality Analysis” (FMECA) methodology has been developed to detect substances, materials, and steps that are critical for the safety of packaging systems used in food contact and related applications. Contamination levels in the finished product beyond acceptable thresholds are screened via a systematic analysis of crossed mass transfer between components and a serialization of mass‐transfer instances during product lifetime. The whole framework, including physical modeling and expert systems, has been integrated within the open‐source simulation software FMECAengine. The whole approach is illustrated on three case studies representative of applications along the food packaging supply chain: (1) identification of critical routes of the contamination by printing ink constituents, (2) concurrent engineering of multipurpose packaging, and (3) application to surveys or control plans. The implementation of this framework within industrial commitments such as compliance with EU regulations and ISO 22000 type food safety management systems is discussed. © 2013 American Institute of Chemical Engineers AIChE J, 59: 1183–1212, 2013