Method for extending the frequency range of sound generators for strength acoustic tests

When determining the service life of modern aircraft, it is necessary to take into account the impact of intense pulsations of sound pressure (the noise created by the operation of engines, air turbulence, changes in flight regimes), etc. on the aircraft structure. Therefore, in ground conditions, acoustic strength and fatigue tests are carried out in special reverberation chambers. During these tests it is necessary to provide a certain spectral density of the sound pressure affecting the structure under study according to the approved standards. Three types of sound generators are used to obtain the desired force impact on the structure: low-frequency, medium-frequency and high-frequency, which must create signals with the required spectral density and constant amplitude of the noise impact each in its frequency range. Nowadays, a high-frequency sound generator operating in the frequency range of 600 – 2000 Hz is being developed. The goal of the study is to modify and improve the moving element of the valve assembly to increase the electromagnetic force driving the valve gate of the valve assembly of a gas flow modulator; minimize the electromagnetic forces hindering movement, and to reduce the mass of the moving element. An increase in electromagnetic driving force is achieved using two electromagnetic thrusters. The proposed modifications reduce hindering electromagnetic forces (Lawrence forces, Foucault forces), and decrease the mass of a movable part of the valve assembly (gate). The goal is achieved by perforating the gate in those parts that are located in magnetic gaps of electromagnetic propulsion.

1. Nikolaev V. S., Kaurova N. F. Installations for acoustic strength tests: a review. — Moscow: TsAGI, 1968. Issue N 565. — 254 p. [in Russian].

2. Aviation rules. Part 25. Airworthiness standarts for transport category aircraft / Interstate Aviation Committee. — Moscow: Aviaizdat, 2009. — 266 p. [in Russian].

3. Nikolaev V. S., Kaurova N. F. Acoustic strength tests in reverberation chambers and traveling wave channels: a review. — Moscow: TsAGI, SNTI, 1982. Vol. 610. — 183 p. [in Russian].

4. RF Pat. 2040043, MKI G10K7/00. Sound generator / Tarchevsky E. P., Miodushevsky P. V.; applicant TsAGI. — N 93027581/10; appl. 13.05.93; publ. 20.07.95 / Byull. Otkryt. Izobret. N 10 [in Russian].

5. Author’s certificate 917193 USSR, MKI G10K7/06. Device for creating acoustic waves / Vasiliev A. V., Revnivtsev V. S., Maslov E. N. (USSR). — N 2909113/18-10; appl. 11.04.80; publ. 30.03.82 / Byull. Otkryt. Izobret. N 12 [in Russian].

6. SU Pat. 1651320, MKI G10K7/06. Electropneumatic sound generator / Ober V. P., Kolennikov A. I., Patrikeev L. I. [et al.]; applicant TsAGI. — N 4489994/10; appl. 24.10.88; publ. 23.05.91 / Byull. Otkryt. Izobret. N 19 [in Russian].

7. RF Pat. 2040043, MKI G10K7/06. Sound generator / Miodushevskij P. V., Tarchevskij E. P., applicant TsAGI. — N 93027581/10; appl. 13.05.93; publ. 20.07.95 / Byull. Otkryt. Izobret. N 10 [in Russian].

8. Hughes W. O., McNelis M. E., Harman A. D., and McNelis A. M. The Development of the Acoustic Design of NASA Glenn Research Center’s New Reverberant Acoustic Test Facility / NASA Glenn Research Center. — Cleveland, OH, 2011. — 344 p.

9. Hughes W. O., McNelis M. E., Harman A. D., and McNelis A. M. The Testing Behind the Test Facility: The Acoustic Design of the NASA Glenn Research Center’s World-Class Reverberant Acoustic Test Facility. Glenn Research Center, Cleveland, Ohio, October, 2010. P. 2.

10. Stevens C. L. Measurement of Acoustic Power of High Intensity Sound Sources / J. Environm. Sci. 1976. Vol. 1 – 11. N 1. P. 7 – 74.

11. Spottswood M. S., Eason T. G., Chona R. A structural perspective on the challenges associated with analyzing a reusable hypersonic platform / Rasd 2013. 11 International Conference, 1 – 3 July, 2013, Pisa.

12. http://www.sereme.com (accessed: 21.04.2023).

13. Galeev A. G., Zakharov Yu. V., Makarov V. P., Rodchenko V. V. Design of set-up for testing objects of rocket and space technology. — Moscow: Izd. MAI, 2014. — 283 p. [in Russian].

14. RF Pat. 2707587, MPK G10K7/06 (2006.01), Sound generation method for testing structures and device for its implementation / Sterlin A. Ya., Furman A. V., Kim S. K., Kutsenko S. A.; applicant TsAGI. — N 2018142903; appl. 05.12.2018; publ. 28.11.2019 / Byull. Otkryt. Izobret. N 34 [in Russian].

15. RF Pat. 2696946, MPK G10K7/06 (2006.01) Electropneumatic sound generator / Sterlin A. Ya., Furman A. V., Kim S. K., Zverev N. V.; applicant TsAGI. — N 2018142901; appl. 05.12.2018; publ. 07.08.2019 / Byull. Otkryt. Izobret. N 34 [in Russian].

16. RF Pat. 2742283, MPK G10K7/06 Gas flow modulator / Sterlin A. Ya., Furman A. V.; applicant TsAGI. — N 2020120957; appl. 25.06.2020; publ. 04.02.2021 / Byull. Otkryt. Izobret. N 4 [in Russian].

17. Sterlin A. Ya., Furman A. V., Kim S. K., Kutsenko S. A. Development of a high-frequency sound generator for acoustic testing of aircraft structures; Models and Methods in Aerodynamics/ International School-Seminar. Evpatoriya June, 4 – 11, 2019. — 148 p. [in Russian].

18. Sterlin A. Ya. The design concept of high-frequency sound modulators for acoustic tests for the strength and flying life on an aircraft / Industr. Lab. Mater. Diagn. 2020. Vol. 86. N 11. P. 60 – 66 [in Russian]. DOI: 10.26896/1028-6861-2020-86-11-60-66

19. Sterlin A. Ya. Method of constructing sound generator for acoustic strength testing of mechanical structures / Uch. Zap. TsAGI. 2022. Vol. LIII. N 4. P. 62 – 68 [in Russian].