飞机单机疲劳寿命监控方法评述

2014-08-15 10:21:25 作者：本站整理来源：

许力蒲，姚卫星
（南京航空航天大学飞行器先进设计技术国防重点学科实验室，南京，210016）

　　摘要：单机疲劳监控对飞机结构的使用安全和寿命潜力挖掘等方面有重要意义。本文将单机监控技术大致分为四个层次：定时维修、重心处载荷谱监控、重心处载荷谱监控兼有危险部位应力场监控、智能监控。对单机寿命监控的学术问题和关键技术问题进行了讨论。
主要学术问题有：1）如何通过监控得到的飞行参数准确得知飞机的实时飞行状态以便计算飞机各部位的载荷；2）在通过重心处的载荷谱转换成疲劳危险部位的载荷谱的计算模型中一般把飞机看作弹性体，但飞机有柔性变形，如何在转换过程中对弹性模型进行修正；3）如何通过实测点处的应变（应力）值反推得到疲劳危险点处的应变（应力）值；4）第2和第3个问题中得到的疲劳危险部位的应力值存在差异，如何度量二者的差异和融合两个应力；5）在单机监控飞机寿命时消除了飞机机群载荷分散性的影响，如何确定载荷分散性系数及飞机剩余寿命的分散性。
主要技术问题有：1）如何将测量得到的大量飞行参数进行预处理；2）当得到外载荷时，如何通过有限单元法（FEM）建立模型计算疲劳危险点的应力；3）如何选取危险部位附近实测点的位置；4）当通过飞行参数计算得到的危险点应力和通过测量点反推得到的危险点应力相差较大时，如何修改计算模型；5）在整个单机监控的过程中存在误差，如何确定误差在过程中的传递以及确定最终的误差。
在单机监控方法中，定时维修和重心处载荷谱监控已经得到了广泛运用，而重心处载荷谱与危险部位应力场监控相结合的方法虽然有着很好的应用前景，但是其诸多学术与技术上的难题没有得到很好的解决，现只在很少的空军部队得到试用，这种方法将是研究的热点，也是以后很长一段时间的主要单机疲劳监控手段。另外，如果智能材料能在飞机结构中得到广泛运用，那么飞机单机监控在技术将得到很大提高。
关键词：单机监控，监控方法，反问题，数据融合

Review Of Fatigue Life Monitoring Of Individual Aircraft
Xu Lipu, Yao weixing^#
(Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China )

　　Abstract: fatigue life monitoring of individual aircraft is important to the safety and mining the potential life of aircraft structure and other aspects. The methods of fatigue life monitoring is divided into four levels: repair maintenance, the monitoring of the load spectrum of center of gravity, the monitoring of the load spectrum of center of gravity with the monitoring of the stress field of the dangerous parts, intelligent monitoring. Academic issues and the key technical issues were discussed.

　　The main academic issues are: 1） How to get the flight conditions accurately by the flight parameters monitored in order to calculate the loads of various parts of the aircraft; 2） The aircraft is generally regarded as elastomeric when the load spectrum of center of gravity is transformed into the load spectrum of dangerous parts, the aircraft, however, is flexible, how to revise the elastic model; 3） How to get the strain（stress） values of the dangerous parts from the strain（stress） values measured.4） There is difference between the stress values obtained in the second issue and third issue, how to measure the distance of the two values and how to fuse them; 5） The load dispersion of the fleet is eliminated by fatigue life monitoring technology, how to determine the load scatter factor and dispersion of the remaining life.

　　The main technical issues are: 1） How large number of flight parameters measured preprocessed; 2） How to build the finite element method （FEM） model to calculate the stress at the dangerous point from the external loads; 3） How to select the position of the measured points near the dangerous parts;4） If the difference of stress at the dangerous point calculated from the flight parameters and calculated from the stress at the measured point is large, how to modify the calculation model; 5） There is an error in the monitoring technology, how to determine the transmittal <app:ds:transmittal>mode <app:ds:mode> of the error and how to calculate the final error.

　　Of the monitoring methods introduced in the first paragraph, repair maintenance and the monitoring of the load spectrum of center of gravity has been widely used. the third level has a broad application prospect, but many academic and technical the problems have not been satisfactorily resolved, now the method gets only a few trials in the Air Force, this approach will be a hot research and will be the major monitoring means for a long time to come. In addition, if smart materials can be widely used in aircraft structures, then the technology in the individual aircraft monitoring will be greatly improved.

　　Keywords: individual monitoring, monitoring methods, inverse problem, data fusion

　　联系方式

　　许力蒲：lipu_xu@163.com

责任编辑：赵泽南

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