Taisomas Diagnostika

Vitalijus Volkovas
'''Diagnostics and Monitoring of Technical Systems:
Methods and Application'''
Kaunas, 2020

TABLE OF CONTENTS
INTRODUCTION…………………………………………………………………………… 
1. PROBLEMS OF RELEVANCE………………………………………………………….
1.1. Energy and concentration of power, failures and mistakes –
reasons of the potential accidents…………………………………………………….
1.2. Industrial facilities and product safety, quality requirements..................………...
1.3. The methodology of evaluation of system’s technical state……………...................
1.4. System monitoring and diagnostics symbiosis……………………………………….
REFERENCES…………………………………………………………………………………
2. MODELS OF DAMAGED MECHANICAL SYSTEMS……………………………….
2.1. Technological system decomposition into elements and analysis 
 of defective states……………………………………………………………………… 
2.2. Models of technical system structural elements……………………………………. 
 2.2.1. Linear dynamics challenges……….…………………………………………...
 2.2.2. Nonlinear dynamics challenges…………………………………………………
2.3. Model of damaged structure’s parameters changing…………...……………………
REFERENCES…………………………………………………………………………………
3. DYNAMICS AND STATE IDENTIFICATION OF HETEROGENEOUS 
SYSTEMS........................……………………………………………………………………
3.1. Systems with lumped parameters …………………………………………………….
3.2 Systems with distributed parameters...................................................................……
3.2.1. The transfer function dentification......................................................................
3.2.2. Dynamics of oblong constructive element and defect identification................
3.2.3. Defect identification in the axis - symmetrical constructive elements.............
3.2.3.1. FEM analysis and state parameters identification……………….…
3.2.3.2. Reaction of the mechanical system to impact load and state 
determination…………………………………………………………….
3.2.4. Dynamics and identification of flexible constructive elements...........................
3.2.4.1. Model of transverse oscillations of a defective belt free span
between pulleys..........................................................................................
3.2.4.2. FEM analysis of the defective belt interaction with the pulley..............
3.2.4.3. A method of belt drives malfunction diagnosis.......................................
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3.2.4.4. Procedure of measuring..........................................................................
3.3. Damaged system’s quazi-harmonic process model..............................................
REFERENCES…………………………………………………………………………………
4. THEORY OF MODERN DIAGNOSTIC METHODS AND MEANS…………………… 
4.1. Controlled dynamic elements in structure’s diagnostics………………………………
4.1.1. The qualitative estimation of defectness of the beam type structures……….
4.1.2. Experimental investigation of the technical state change and defect
localization in beam type structures……………………………………………
4.1.3. The diagnostic methods, based on the dynamics of structure with
additional mass………………………………………………………………….
4.2. Inspection using mechanical energy converting elements ……………………………
4.2.1. The mechanical energy conversion into electricity model………………........
4.2.2. Practical aspect of application and new devices................................................
4.3. Some aspects of vibration and impact analysis in systems diagnostics........................ 
4.3.1. Evaluation of quality of heterogeneous mechanical systems
using impedance method……………………………………………………….
4.4.2. Vibro shock signals in rotating system…………………………………………
4.4.3. Simulation of vibro shock signals in rotating system………………………….
4.4. Multi-layer cylindrical structures diagnostics based on 
Lamb’s wave’s interference………………………………………………………….....
4.4.1. Waves propagating within the cylindrical structure and interference 
phenomenon……………………………………………………………………..
4.4.2. A technique of signal processing for interferometric estimation 
of the amount of deposit in pipes………………………………………………..
4.5. Acoustic emission (AE): research and new aspects…………………………………….
4.5.1. AE method in the rotating machine elements…………………………………..
4.5.2. AE testing of pressurized vessels and cylinders…………………………………
REFERENCES…………………………………………………………………………………
5. DEVELOPMENT AND APPLICATION OF MONITORING AND DIAGNOSTICS……
5.1. Permanent vibration monitoring and diagnostics of unique machines (UM)…………
5.1.1. Vibration monitoring and diagnostic systems of turboagregate…………………
5.1.2. Monitoring the technical condition of hydroelectric power plants………………
5.1.3. Vibroacoustic diagnostics of rolling bearings using stationary system…………
5.2. Periodic vibration diagnostics of rotor systems with portable devices ……………….
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5.3. Adaptable vibration monitoring in rotor systems ………………………………………
5.3.1. Concept and principles of adaptive monitoring………………………………….
5.3.2. Realization of adaptive bearing defect detection…………………………
5.3.3. Adaptive monitoring algorithm………………………………………………
5.5. Vibrodiagnostics problem in small hydroelectric power plants (SHPP)…………..
5.5. The concept of buildings stability monitoring and damage diagnostics……………
5.5.1. Concept of building’s stability.................................................................................
5.5.2. Models of building and defects...................................................................................
5.5.3. Building’s stability monitoring system (BSMS)..........................................................
5.5.4. Results of laboratory experiment...................................................................................
5.6. Development of new measurement elements for vibration monitoring systems...............
5.6.1. Low frequency vibration measurement device: creation and investigation............
5.6.2. Air gap measuring system for purpose of diagnostics and condition monitoring...
REFERENCES………………………………………………………………………………………
6. UNCERTAINTY IN MONITORING AND DIAGNOSTIC SYSTEMS...................................
6.1 Uncertainty in vibration monitoring systems of rotating machinery …………………….
6.2. Uncertainty sources in vibration monitoring and diagnostic systems……………………
6.2.1. Calculating measurement uncertainty in vibromonitoring systems………………
6.2.2. Increase of mean and variance estimates reliability for limited data size……….
6.2.2.1. Theory of the method……………………………………………………
6.2.2.2. The results of statistical simulation……………………………………
6.2.2.3. Practical application of the method……………………………………
6.2.3. The measurement uncertainty with random or systematic errors………………
6.2.3.1. Rotating machinery as a measurement object………………………..
6.2.3.2. Vibromonitoring system as a measurement medium………………….
6.2.3.3. Analysis of experimental data…………………………………………
6.2.4. Uncertainty of decision making…………………………………………………….
6.3. Investigation of vibration monitoring uncertainty including transient modes
of rotating systems....................................................................................................................
REFERENCIES………………………………………………………………………………………