Vibroacoustic Condition Monitoring





                                       Table of contens



1        Introduction

          1.1     Origin of machinery diagnostics and vibroacoustical diagnostics
                    1.1.1.     Machine diagnostics 
                    1.1.2.     Vibroacoustical diagnosis
          1.2     Possibilities of machine condition testing and vibroacoustical diagnostics
          1.3     The place of vibroacoustical diagnostics in machine life 
                    1.3.1.     Design diagnostics
                    1.3.2.     Checkout diagnostics
                    1.3.3.     Condition monitoing
                    1.3.4.     Diagnostics of  production processes
2       Generation of vibroacoustical phenomena and wear processes

         2.1     Introduction
         2.2     Sources of vibroacoustical processes in machinery
                   2.2.1.     Unbalance
                   2.2.2.     Misalignment of shafts, couplings clearances
                   2.2.3.     Critical rotations of the second order 
                   2.2.4.     Self-excited vibrations of bearings
                   2.2.5.     Rolling bearings as the sources of vibrations
                   2.2.6.     Toothed gears
                   2.2.7.     Magnetic sources of machine vibrations
                   2.2.8.     Motion of the working medium
                   2.2.9.     Cavitation
                   2.2.10.   Frictional vibrations
                   2.2.11.   Acoustical emission
                   2.2.12.   Range of vibroacoustical phenomena in machinery and structures   
         2.3.    Machine wear and vibroacoustical phenomena
                   2.3.1.      Introduction
                   2.3.2.      Fatigue wear
                   2.3.3.      Frictional wear
                   2.3.4.      Cavitation ear
                   2.3.5.      Changes of  form - creep
                   2.3.6.      Tribovibroacoustical model of a machine

         2.4.    Summary
     Failure - oriented process signals and measures of vibroacoustical phenomena
         3.1     Introduction
         3.2     Observation models of tribovibroacoustical phenomena in machines
                   3.2.1.     Failure life 
                   3.2.2.     Model of diagnostic observation of an object - vibroacoustical signal
                   3.2.3.     Measures of vibroacoustical signals - symptoms, discriminants
                   3.2.4.     Observation area of vibroacoustical  processes in machinery diagnostics 
          3.3    Selection of the diagnostically useful vibroacoustical processes
                   3.3.1.     A tribological model of the generation and propagation of vibroacoustical phenomena
                   3.3.2.     Generation of diagnostic signals
                   3.3.3.     Selection of the observed vibroacoustical process as the source of diagnostics information
          3.4    Selection of vibroacoustical signals
                   3.4.1.     Spatial selection
                   3.4.2.     Time selection of vibroacoustical signals
                   3.4.3.     Spectral selection
                   3.4.4.     Selection of vibroacoustical signal by demodulation
                   3.4.5.     Decomposition of signals and periodic adaptational filtration

           3.5   Diagnostic measures of vibroacoustical signals and their application
                   3.5.1.     Introduction
                   3.5.2.     Amplitudes of noise and vibration in the diagnostics of simple machines
                   3.5.3.     Special point estimators of vibroacoustical processes
                   3.5.4.     Spectral and kinematic analyses in vibroacoustical diagnostics
                   3.5.5.     Special functional spectral measures of vibroacoustical processes
                   3.5.6.     Spectral sensitivity of the measures of vibroacoustical processes
           3.6   Summary 

4        Diagnostic inference  
          4.1    Introduction
          4.2    Diagnostic models and decisions concerning
                   4.2.1     Diagnostic regression model
                   4.2.2.    Covert model of  image type
                   4.2.3.    Probabilistic diagnostic model of a mechanical object 
                   4.2.4.    Accuracy of diagnostic decisions 
          4.3    The limit value of the symptom of the first class condition 
                   4.3.1     Introduction
                   4.3.2.    Life curve of object and limit value of symptom
                   4.3.3.    Limit value in the passive diagnostic experiment

          4.4    Simple and generalized condition symptoms - filtration of disturbance
                   4.4.1.    Introduction
                   4.4.2.    Linear averaging in respect to utilization time and the object's span
                   4.4.3.    Geometrical averaging - cumulants

          4.5    Condition prognosis    
                   4.5.1.    Introduction
                   4.5.2.    Prognosis according to a known condition - symptom model
                   4.5.3.    Condition prognosis with an unknown trend model

          4.6    Summary

5        Examples of the implementation of diagnostics in industry
          5.1    Introduction
          5.2    General scheme of the implementation of vibroacoustical diagnostics
          5.3    Diagnostics of high- power fans in power engineering 
          5.4    Diagnostics of diesel traction engines
          5.5    Diagnostics of godets of textile machines 
          5.6    Diagnostics of electric motors
          5.7    Summary

6        Advanced problems of vibroacoustical diagnostics
          6.1    Introduction
          6.2    Diagnostic experiments 
          6.3    Discrimination of vibroacoustical condition characteristics and classification in a passive experiment 
                   6.3.1.    BEDIND - algorithm of discrimination and classification 
                   6.3.2.    Discrimination of characteristic features by the orthogonalization method of observation vector components 
          6.4   Recognition of condition 
          6.5   Discrimination of failure signals 
                   6.5.1.    Adaptive noise cancelling 
                   6.5.2.    Orthogonal filtration of signals 
                   6.5.3.    Diagnostic filtration of signals 
          6.6    Summary
    A1    Important standards of machine vibration diagnostics 
    A2    Diagnostic chart of rotary motion machines
    A3    Criteria of rotor balance
    A4    Computation nomogram of harmonic vibrations






Update 08 November 2009