logo

Vibrations in engineering and technology

space SCIENTIFIC JOURNALS OF VINNITSA NATIONAL AGRARIAN UNIVERSITY

Issue №: 3 (102)

Published: 2021.09.28
DOI: 10.37128/2306-8744-2021-3


Description:
The journal deals with the problems of vibration technologies and machines, mathematical methods of vibration process studies, information on design and technological development, presents teaching and methodological aspects of teaching in the Higher School of Applied Sciences, where vibration machines and technologies are studied.

Read about journal

VIBRATION DIAGNOSTICS OF FATIFUE DAMAGE IN STRUCTURAL ELEMENTS OF GAS TURBINE ENGINES AT THE REPAIR STAGE

DOI: 10.37128/2306-8744-2021-3-1
PDF Повернутись

Bovsunovsky Anatoliy Petrovich – Doctor of Technical Sciences, Professor, Professor of the Department of Heat Power Engineering of National Technical University of Ukraine " Igor Sikorsky Kyiv Polytechnic Institute ", 03056, 37 Peremohy Ave., Kyiv, Ukraine; e-mail: apbovsunovsky@gmail.com).

 

Annotation

Vibration diagnostics of damage belongs to the class of non-destructive methods, which usually do not take long time. However, the main problem of vibration diagnostics is relatively low sensitivity to the critical damage of fatigue crack type, which arises because of long time accumulation of plastic deformation. To improve the sensitivity and reliability of vibration diagnostics of damage two methods were considered. First method was based on the fact, that a characteristic feature of vibrations of structural elements with fatigue crack is the occurrence of non-linear resonances (sub- and super-harmonic) and significant non-linearity of vibration response at these resonances. Secon one – on the fact, that quite noticeable in certain cases increase of damping characteristic caused by a crack can be observed. Analytical and experimental studies of these methods were carried out as applied to the blades of aircraft gas turbine engines. As a result of the studies, the intensity of change in parameter of super-harmonic resonance and in damping characteristics at different parameters of crack was determined. Besides, the experimental techniques for vibration testing of turbine blades were developed. There was demonstrated, that the sensitivity of both considered methods of vibration diagnostics is several orders of magnitude higher than the sensitivity of conventional methods based on the change in natural frequencies and mode shapes, and they can be effectively used for the diagnostics of blades on the stage of engine repair. All the other conditions being equal, second-order superharmonic resonance demonstrates a higher sensitivity to the presence of cracks than the damping characteristic. The smallest crack with an area of 0.2% considered in the work causes a reliably recorded non-linearity of vibration response at superharmonic resonance of order of 2/1. At this the change of damping characteristic slightly exceeds the error of experiment.

Keywords: Damage detection; super-harmonic resonance; damping characteristic; aircraft gas turbine engine; blades of turbine.

List of references

1. Nalimov Yu. S. (2014). Analysis of damage of gas turbine engines blades. Metal and Casting of Ukraine, 12(259), 17-22. 

2. ОST-1-00304-79. Lopatki gasoturbinnyh dvigateley. Normirovanie povregdenia lopatok kompressorov ot popadania postoronnih predmetov, 1979.

3. Bovsunovsky A., Surace C. (2015). Non-linearities in the vibrations of elastic structures with a closing crack: A state of the art review. Mechanical Systems and Signal Processing., 62-63, 129-148.

4. Afolabi D. (1987). An anti-resonance technique for detecting structural damage. Proc. of the 5th IMAC, London, 491-495.

5. Collins K.R., Plaut R.H., Wauer J. (1992). Free and forced longitudinal vibrations of a cantileverd bar with a crack. ASME J. of Vibration, Acoustics, Stress, and Reliability in Design, 114, 171-177.

6. Tsyfansky S.L., Beresnevich V.I. (2000). Non-linear vibration method for detection of fatigue cracks in aircraft wings. J. of Sound and Vibration, 236(1), 49-60. 

7. Bovsunovsky A.P. (2019). Efficiency of crack detection based on damping characteristics. Engineering Fracture Mechanics, 214, 464–473. 

8. Bovsunovskii A.P. (2001). Vibrations of a nonlinear mechanical system simulating a cracked body. Strength of Materials, 33(4), 370–379.

9. Bovsunovsky A.P. (2004). The mechanisms of energy dissipation in the non-propagating fatigue cracks in metallic materials. Engineering fracture mechanics, 71(16-17), 2271-2281. 

10. Bovsunovsky A.P., Surace C. (2005). Considerations regarding superharmonic vibrations of a cracked beam and the variation in damping caused by the presence of the crack. Journal of Sound and Vibration, 288(4-5), 865-886. 

11. https://en.wikipedia.org/wiki/Lotarev_D-36.

12. Bovsunovsky A.P., Kratko A.G. (1998). The shape of mechanical hysteresis loops for metals under harmonic loading. J. of Testing and Evaluation, 26(1), 31-37.

13. Pisarenko G.S., Yakovlev A.P., Matveev V.V. (1971). Vibration absorbing properties of structural materials (Handbook). Kiev: Naukova Dumka.  

14. Bovsunovskii A.P. (1999). Numerical study of vibrations of a nonlinear mechanical system simulating a cracked body. Strength of Materials, 31(6), 571–581.

15. Bovsunovskii A.P., Surace C., Bovsunovskii O.A. (2006). The effect of damping and force application point on the non-linear dynamic behavior of a cracked beam at sub-and superresonance vibrations. Strength of Materials, 38, 492–497. 

16. Bovsunovskii A.P. (2007). Comparative analysis of nonlinear resonances of a mechanical system with unsymmetrical piecewise characteristic of restoring force. Strength of Materials, 39, 159–169.

 

All journal issues

About journal

Topics of the journal:

The journal "Vibrations   in engineering  and technology" presents materials on the following issues

• Theory of processes and machines
• Mechanical Engineering and materialprocessing
• Processing and food production

Key information:
ISSN (print): 2306-8744
DOI: 10.37128/2306-8744

The certificateof massmediaState registration:kv no 16643-5115 from 30.04.2010 .
Founder of the journal: Vinnytsia National Agrarian University

Kind of publication: journal
Type of publication : Scientific
Publication status: Domestic
Year of founding:
Periodicity: 4 times a year
Extent: 18.75 nominal printed pages
ISSN: 2306-8744 (printed version), (online)
Language of edition  : (mixed languages) Ukrainian, English
The scope of the distribution and the category of readers: national, foreign, teaching staff, scientists, businessmen.
Periodical is included in the list of scientific professional editions of Ukraine approved by the Order of Ministry of Education and Sciences of Ukraine from 21.12.2015 No. 1328.
The journal "Vibrations in engineering and technology" is included in the "Catalogue of periodicals of Ukraine".
Journal subscription can be executed in each post office department.
 Subscription Index is  99720.

 

Old version of site: http://vibrojournal.vsau.edu.ua/

History of journal:

In June 1994 the 2nd International Scientific and Technical Conference "Application of vibrations for technological purposes" was organized on the basis of Vinnytsia State Agricultural Institute. Leading experts in this field, noting the significant contribution to the school of Vibration Engineering under the leadership of P. S. Bernyk, proposed to create a professional all-Ukrainian scientific and technical journal "Vibration in engineering and technology..The journal was foundedat Vinnytsia State Agricultural Institute and P.S. Bernyk was elected to be the chief editor .
For all these years (since 1994) theJournal "vibration in engineering and technology" published  94 issues wherestudy of vibration effects, the creation of progressive energy saving technologies and equipment for their implementation were highlighted.
Currently Kaletnik H.M  PhD , professor, academician NAAS is the chief editor of the "Vibrations in engineering  and Technology"
The journal "Vibration in Engineering and technology", which has no analogues on the territory of Ukraine, is well known abroad.