Design Of An Aero-engine Whole Body Vibration Fault Diagnosis System

Aero-engine often exists abnormal work due to the excessive vibration, and the reason ofexcessive vibration can be obtained through the analysis of the whole machine vibration testdata.Therefore, using the database to store the machine vibration test data of aircraft engine,designing aero-engine vibration fault diagnosis system has certain practical significance. Inthis paper, aero-engine vibration fault diagnosis system is designed by studying the wholemachine vibration characteristics of an aero-engine.First of all, using analytic hierarchy process theory to establish the vibration stateevaluation index system of an aero-engine, and determine the weights of evaluation indexes.On the basis of the theory of probability and statistics to determine the membership functionof the evaluation indexes. Using fuzzy comprehensive evaluation theory to establish thewhole body vibration state evaluation model of aero-engine, which is applied to evaluate thevibration state of the aero-engine and various typical section. The evaluation result shows thatthe model can implement the evaluation of vibration state.Secondly, the information exergy feature which reflects the change rule of aero-enginevibration fault process was extracted, by studying the vibration characteristics of anaero-engine. The support vector machine (SVM) fault diagnosis theory is applied to establishaero-engine vibration fault diagnosis of SVM model. The model is used to diagnose theaero-engine vibration fault. Result shows the model can implement the classification anddiagnosis of aero-engine vibration fault.Finally, reference on the methods and principles of database design, study deeply therequirement analysis of whole machine vibration fault diagnosis system, establish E-R modelof fault diagnosis system, and design the entity list of fault diagnosis system. The aero-enginevibration state evaluation function module and the whole machine vibration fault SVMdiagnosis function module were designed by using the methods of vibration state evaluationand fault diagnosis. Fault diagnosis system for each typical cross section of an aero-engine vibration and vibration state comprehensive assessment, and through the graphic displaymode quickly compare the vibration state of the section, a typical implementation of theaero-engine rotor imbalance, of the shafting crack and grinding four kinds of typical faultdiagnosis and other application function.