故障率相关下数控车床预防维修策略研究

发布时间：2018-03-10 10:21

本文选题：数控车床　切入点：DEMATEL/ISM　出处：《吉林大学》2017年博士论文　论文类型：学位论文

【摘要】：数控车床作为制造型企业的核心设备,其安全、无故障的运行对企业在市场上保持自身核心竞争力有重要的影响。制定科学、合理的维修策略是保障数控车床正常运行的关键。数控车床是集机、电、液等于一体的复杂系统。系统复杂的结构,造成其故障具有相关性特征,即便一个部件极为微小的故障,也会因为复杂系统的规模效应,引起系统整体故障率的增长,继而引发维修费用增高,停机损失巨大,甚至会发生严重的事故后果等问题。因此,本文以数控车床为研究对象,在分析故障相关性的基础上,围绕数控车床的预防维修策略展开研究。首先,对数控车床相关故障进行分析。将数控车床分为若干组件要素,对具有相关故障的数据进行统计、分析,列明要素间故障关联关系。根据DEMATEL方法得到反映故障影响关系和程度的组件间综合故障影响矩阵,并应用ISM法构建故障相关组件间结构关系模型,进一步明确组件故障间的传递性、层次性。其次,基于数控车床组件故障过程建模制定组件更换策略。为使组件更换时间的制定及备件库存量的估计更加准确,在考虑故障时间相关性的基础上,提出了数控车床组件的更换策略。对组件的故障数据进行平稳性及趋势检验后,通过Johnson法修正系统组件故障时间的次序,建立故障过程模型,根据数控车床实际运行数据确定组件更换时间、预测备件数量。再次,在进行数控车床故障率相关性研究的基础上,制定了数控车床整机的预防维修间隔时间。根据前文对数控车床组件故障相关性分析,将数控车床组件分为故障源组件及非故障源组件两类情况进行可靠性建模。通过偏差修正的方法,对所建立的故障源组件可靠性模型进行修正,并应用D检验法验证了偏差修正的效果,据此得出故障源组件的可靠性模型。为提高计算结果的准确性,对于非故障源组件的故障数据使用平均秩次法对故障次序进行修正,运用最小二乘法进行参数估计,采用相关系数法及D检验法分别进行线性相关性检验及假设检验,建立故障独立下的各个非故障源组件可靠性模型。引入Copula函数作为连接函数,建立了故障相关下组件的联合可靠性函数;通过计算Kendall秩相关系数,对Copula函数进行参数估计,并计算出各故障相关组件间的相关系数,据此建立故障率相关下非故障源组件可靠性模型。在确定数控车床组件及整机的综合故障率后,分别从可用度和维修费用两个角度,制定数控车床的最佳预防维修间隔时间。最后,构建了基于可用性评估的数控车床预防维修决策模型,依据企业中7台数控车床的可用性评估结果制定相应的维修方案。提出综合运用可靠性、维修性、安全性等可用性评价指标对某企业数控车床可用性进行评价。为使评价结果兼具主观和客观性,综合了模糊层次分析法获得的主观权重及熵权法获得的客观权重,得到评价指标的组合权重,同时引入灰色聚类法,分别评估每台数控车床的可用性等级。根据数控车床可用性的评价结果选用适当的预防维修及维护方案。本文结合数控车床的故障特点,进行了故障率相关下数控车床预防维修策略研究,为企业的数控车床维修管理工作提供了有益的参考。
[Abstract]:CNC lathe as the core equipment manufacturing enterprises, its safety, trouble free operation has an important influence on the enterprises to maintain their core competitiveness in the market. To formulate a scientific and reasonable maintenance strategy is the key to ensure the normal operation of CNC lathe. The CNC lathe is set machine, electricity, liquid complex system is one of the complex system. The structure, causing the failure of the correlation characteristics, even a very small part of the fault, also because of the scale effect of complex system, the whole system caused by the failure rate of growth, leading to increased maintenance costs, downtime huge losses, even accident consequences and other serious problems. Therefore, based on the CNC lathe the object of study, based on the analysis of fault correlation, focuses on the research of preventive maintenance strategy of CNC lathe. Firstly, related to the failure analysis of CNC lathe CNC Lathe will be divided. For a number of component elements, statistics, analysis of relevant fault data, list the elements of the fault relation. According to the method of DEMATEL reflected the degree and effect of fault component relationship between fault influence matrix, and the application of ISM method to build fault related components structure model, further clear the transmission component failure, the level. Secondly, component failure of CNC lathe process modeling to develop component replacement strategy based on estimated formulation and spare parts inventory makes the component replacement time is more accurate, considering the fault time dependence on the proposed replacement strategy for CNC lathe components. The fault data on component test stationarity and trends correction, system component failure time by Johnson method in order to establish the fault process model, data to determine the component change time according to the actual operation of CNC lathe, Forecast the quantity of spare parts. Thirdly, based on the fault rate of CNC lathe correlation research, developed a time interval preventive maintenance of CNC lathes. According the above analysis of CNC lathe CNC lathe assembly fault correlation, the component for the fault source component and non fault source component in two categories for reliability modeling. Through the method of deviation correction the source of fault component reliability model was modified, and the application of D test method to verify the effect of deviation correction, reliability model to derive the fault source component. In order to improve the accuracy of the calculation results, the fault data of non fault source component using the mean rank method to correct the fault sequence, using the least squares method for parameter estimation, using the correlation coefficient method and D test method were linear correlation test and hypothesis testing, the establishment of various independent under the fault Non fault source component reliability model. By using the Copula function as the link function, to establish a joint reliability function of fault related components; by calculating the Kendall rank correlation coefficient, parameter estimation of the Copula function, and calculate the correlation coefficient of each fault correlation between components, based on the failure rate related to non fault source component reliability model. In determining the fault component and the CNC lathe rate, respectively from two angles of availability and maintenance cost, best preventive maintenance intervals make CNC lathe. Finally, the construction of preventive maintenance decision model of CNC lathe can be used based on the assessment, according to the corresponding maintenance schemes make usability evaluation enterprise 7 the results of numerical control lathe. Made comprehensive use of reliability, maintainability, security and usability evaluation index to evaluate the enterprise of a CNC lathe for availability. The evaluation results of both subjective and objective, comprehensive objective weights fuzzy AHP subjective weight and entropy method was obtained by the combined weights of evaluation indexes, and introduces the grey clustering method, respectively, to evaluate the usability level of each CNC lathe. According to the evaluation results of the numerical control lathe availability and use of preventive maintenance the appropriate maintenance program. Based on the fault characteristic of NC lathe, the fault rate of CNC lathe related preventive maintenance strategy research, provides a useful reference for the management and maintenance of CNC lathe.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TG519.1

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