Şok Sönümleyiciye Sahip Cihazın Montaj Arayüzünün Yorulma Ömrünün Hesaplanması

Öz

Hava araçları titreşim yükleri altında çalışmaktadır ve bu yükler parçalarda titreşim kaynaklı yorulma hasarına sebep olmaktadır. Yorulma hasarları öncesinde bir uyarı vermeden aniden oluşması nedeniyle tehlikeli hasarlardır bu yüzden dikkatlice analiz edilmesi gerekmektedir. Analizlerde özellikle doğal frekansların ve sönümlemelerin doğru belirlenmesi gerekir çünkü titreşim yüklerinin doğal frekanslarla çakışması durumunda rezonans gözlenir ve bu parçanın ömrünü azaltır. Bu çalışma kapsamında şok sönümleyiciye sahip bir cihazın montaj arayüzünün yorulma ömrü analiz edilmiştir. Analize girdi olması amacıyla gerçek uçuş senaryolarında uçuş testleri gerçekleştirilmiştir. Şok sönümleyicilerinin doğru modellenmesi için modal test yapılmıştır. Hazırlanan sonlu elemanlar modelinin doğruluğunu kanıtlamak ve sönümleme oranlarının tespiti için titreşim testi yapılmıştır. Yorulma analizleri ticari bir yazılım olan nCode ile frekans düzleminde yapılmış ve analizin doğruluğu yapılan test ile kanıtlanmıştır.

Anahtar Kelimeler

• Yorulma Analizi
• Şok Sönümleyici
• Sonlu Elemanlar Modeli

Predicting Fatigue Life of A Mount of A Device with Shock Absorber

Öz

All aircraft operate under vibration loads and these loads cause vibration-induced fatigue damage to the parts. Fatigue damages are dangerous because they occur suddenly without giving a warning before, for this reason they need to be carefully analyzed. In the analysis, especially the natural frequencies and dampings must be determined correctly, because when the vibration loads match with the natural frequencies, resonance is observed and this reduces the life of the part. In this study, the fatigue life of a mount of a device with shock absorber is investigated. Flight tests were carried out in real flight scenarios to provide an input for the analysis. A modal test was performed to model the shock absorbers correctly. Vibration test was performed to prove the accuracy of the prepared finite element model and to determine the damping ratios. Fatigue analyses were performed in frequency domain with a commercial software, nCode, and the accuracy of the analysis was proven by the experiment.

Anahtar Kelimeler

• Fatigue Analysis
• Shock Absorber
• Finite Element Method

Kaynakça

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