【作者】 许磊；

【导师】 曹华军；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2017， 博士

【摘要】 机械装备再制造是一种以损伤退役零部件为再制造毛坯,采用高新再制造技术手段,实现机械装备“以旧造新”的可持续制造模式,其目标是延长产品的服役年限,降低资源消耗与环境污染,提高资源利用率,其实质是利用技术创新充分挖掘退役产品的剩余价值,进一步促进资源节约型与环境友好型的两型社会建设进程。我国作为机械装备制造业大国,将面临大量的退役机械装备,开展再制造领域相关的问题研究,能够有助于缩小我国与发达国家装备再制造技术水平差距,实现我国再制造产业化健康发展。再制造产品的核心挑战是如何提高其服役安全及服役寿命,其中作为关键技术之一的再制造产品安全服役寿命预估因涉及到多个学科及领域,亟需相关理论支持。本论文将结合国家973重点基础研究计划课题之一“再制造零部件的寿命预测与再制造产品服役安全验证”(2011CB013405)和高校博士点基金课题“再制造机械零部件服役寿命演变机理及预测方法研究”(20110191110005)等课题,以离心压缩机失效叶轮为研究对象,开展考虑损伤模糊性的再制造叶轮安全服役寿命数值预估及支持系统研究,为再制造零部件安全服役寿命提供理论支撑。首先,针对叶轮失效过程中的疲劳损伤模糊性特点,建立基于模糊理论的Miner准则修正模型;对影响再制造叶轮疲劳损伤的影响因素如毛坯质量等进行深入分析,搭建疲劳损伤量评价标准体系,并建立基于模糊综合评价方法的再制造叶轮疲劳损伤评估模型。综合考虑再制造叶轮服役寿命预估时疲劳损伤存在的模糊特性,建立基于模糊理论的疲劳损伤修正模型为服役寿命预估提供科学依据。其次,根据再制造叶轮安全服役特性,在再制造叶轮安全性评测的基础上,结合疲劳损伤模糊性与服役载荷特性等,建立以再制造叶轮安全评估,考虑疲劳损伤模糊性修正模型,安全服役载荷耦合模型和材料疲劳极限修正模型等为核心内容的安全服役寿命预估模型,为实现安全服役寿命预估提供一种理论方法。然后,采用三维造型理论和有限元建模技术解决叶轮毛坯“盲件”属性问题,建立能够反映失效特征的再制造叶轮几何模型和全六面体有限元网格模型;利用实验与数值模拟方法,重点分析再制造叶轮激光熔覆残余应力载荷;建立离心应力载荷与气动应力载荷服役载荷模型,并对叶轮尾流激振下的模态规律进行分析。上述载荷模型为安全服役载荷谱提供科学支撑。再次,通过构建非对称应力状态下的叶轮材料疲劳寿命模型,建立FV520B材料疲劳极限修正模型;分析再制造叶轮服役工况特性,基于载荷雨流计数理论对其特征载荷进行解析;开展疲劳损伤模糊性分析并通过Fe-safe软件实现再制造叶轮的安全服役寿命预估,讨论并分析不同残余应力、叶轮转速等特定工况下的相对疲劳寿命。最后,以有限元分析软件ANSYS为平台,利用Visual Basic(VB)与SQL server2005等开发一套适用于大型离心式压缩机再制造叶轮安全服役寿命预估的支持系统,应用该软件可开展再制造叶轮安全服役寿命数值分析。更多还原

【Abstract】 The remanufacturing of mechanical equipment is a sustainable manufacturing mode taking damaged or decommissioned parts as remanufacturing blanks,using remanufacturing techniques and realizing “turning an old part into a new one” so as to prolong the service life of products,reduce resource cost and environmental pollution and increase resource utilization rate.Using technical innovation to fully tap the surplus value of retired products is the essence of remanufacture,which can further speed up the construction progress of a resource-saving and environment-friendly society.China has become a global mechanical equipment manufacturing power and an increasing number of mechanical equipment have been or are going to be retired.Therefore,studying the basic of remanufacturing science helps to improve the equipment remanufacturing level and ensure the smooth development of remanufacturing industrialization in China.The core challenge of remanufacturing is how to improve the safety and prolong the service life of remanufactured products.Besides,the estimation of safety and service life of remanufacturing product,one of key technologies in remanufacturing,is in urgent need of theoretical support as it involves many subjects and fields.Supported by the National Basic Research Program of China,named “Life Prediction of Remanufacturing Parts and Service Safety Verification of Remanufacturing Products”(No.2011CB013405),the Specialized Research Fund for the Doctoral Program of Higher Education of China,named “Study of Evolution Mechanism and Prediction Method of Remanufacturing Mechanical Parts”(20110191110005),and other programs,this paper focused on the study of the remanufacturing impeller of centrifugal compressor,including the research of the safety service life amount prediction and supporting system of centrifugal compressor remanufacturing impeller by taking the damage fuzziness into consideration,to provide the safety service life of remanufacture parts with theoretical support.Firstly,as for the problem of fuzziness characters existing in calculating the fatigue damage,the modification model of Miner criterion based on fuzzy theory was created.Factors affecting remanufacturing impeller fatigue damage like blank quality were deeply analyzed;the evaluation standards for fatigue damage amount were constructed;the evaluation model of remanufacturing impeller fatigue damage was built based on Fuzzy Comprehensive Evaluation(FCE).The fatigue damage modification model based on fuzzy theory was built after considering the fuzziness in remanufacturing impeller life prediction to provide scientific basis for service life prediction.Secondly,based on remanufacturing impeller safety service feature,remanufacturing impeller safety evaluation and fatigue damage fuzziness and service load features,the safety service life prediction model centering on the remanufacturing impeller safety evaluation,modification model considering fatigue damage fuzziness,safety service load coupling model and material fatigue limit modification model to provide a theoretical reference for the safety service life prediction.Thirdly,3D modeling theory and finite element modeling technique were adopted to solve the property problem of “blind piece” and build the remanufacturing impeller geometric model and all-hexahedral FEM mesh model,which can reflect failure features;on this basis,use experiments and numerical simulation technique to analyze the residual stress load of remanufacturing impeller laser cladding;the coupling model of centrifugal stress load and pneumatic stress load was built;modes rule in wake excitation produced by impeller was also analyzed.The above research models offers scientific support to safety service load spectrum.Furthermore,the modification model of FV520 B material fatigue limit was established by building impeller material fatigue life model in asymmetric stress state;by analyzing remanufacturing impeller service working condition characters,based on load rain-flow counting theory,the load spectrum was analyzed.The safety service life of remanufacturing impeller was predicted by conduct fatigue damage fuzziness analysis and applying Fe-safe software.Besides,relative fatigue lives of remanufacturing impeller in different residual stress,rotation speed and other special working conditions were discussed.Finally,a support system designed to predict the safety service life of remanufacturing impeller of large centrifugal compressor was developed by taking finite element analysis software – ANSYS as a platform and using Visual Basic(VB)and SQL server 2005,which can be used to conduct numeric analysis of remanufacturing impeller safety service life.更多还原