Structure fatigue crack in the effect of acoustic load : case study

• Autorzy: Wiśniowski W.

Identyfikatory

DOI

10.5604/12314005.1130520

• Języki publikacji: EN

Abstrakty

EN

The paper presents a method for detection mechanisms and prevention of the fatigue cracks caused by acoustic loads acting on the aircraft elevator structure. During aircraft inspection, the fatigue cracks in elevator rib caps were discovered. The theory emerged, that cracks were caused by acoustic extortion on elevator sheet covering, caused by jet engine exhaust airstream, engine gas flow expanding in convergent nozzle and acting as the source of the strong acoustic load. To prove this theory, investigations were arranged, in which the strains in the elevator sheet skin, between the ribs area, were determined in harmonic excitation. The results, after frequency analysis, showed strong resonance in 270 Hz area. Mode of this resonance caused drumming of covering, resulting in bending of the ribs caps and causing them to fail from fatigue. Changes in elevator design raised the resonance frequency and lowered strains in modified elevator covering. The changes mainly increased sheet-covering stiffness by increase of thickness and lowering the sheet-metal covering mass in selected places, mainly by technological means - metal bonding (gluing) and metal covering chemical milling.

Słowa kluczowe

EN

acoustic loads; resonance tests; fatigue cracks

• Wydawca: Łukasiewicz Research Network - Institute of Aviation ; European Science Society of Powertrain and Transport KONES Poland ; Wydawnictwo Instytutu Technicznego Wojsk Lotniczych
• Czasopismo: Journal of KONES
• Rocznik: 2014
• Tom: Vol. 21, No. 4
• Strony: 533--536
• Opis fizyczny: Bibliogr. 3 poz., rys.

Twórcy

autor

Wiśniowski W.

• Institute of Aviation Krakowska Av. 110/114, 02-256 Warsaw tel.: [phone], fax: [phone]

Bibliografia

• [1] Wiśniowski, W., Pomiary i porównanie naprężeń pokrycia sterów samolotów wzbudzanych pracą silnika samolotu TS.ll, Sprawozdanie Instytutu Lotnictwa 8/BW-WZ/90.
• [2] Wiśniowski, W., Sposób pomiaru drgań przy pomocy tensometrów skalowanych dynamicznie zgodnie z postaciami drgań własnych w zastosowaniu zwłaszcza do badań konstrukcji lotniczych, Patent 156 768.
• [3] Wiśniowski, W., Badania rezonansowe obiektów łatających - metody i analiza wyników, Transactions of the Institute of Aviation, No. 209, Warsaw 2010.