Belirsizliklerin yorulma ömrü üzerindeki etkilerinin aralık sayılar kullanarak analizi

Büyüklüğü zamanla değişen yüklemeler altında mühendislik yapılarındaki küçük yorulma çatlakları, daha sonrasında gelişerek ani ve yıkıcı hasarların oluşması gibi tehlikeli sonuçlara ulaşabilmektedir. Yorulma Çatlak Büyümesi (FCG) ömrünün güvenli bir aralıkta tanımlanması, bir sistemin işletme yükleri altında emniyetli bir şekilde çalıştırılması için son derece önemlidir. Bu sayede doğru bir bakım ve servis aralığının tespiti öngörülerek söz konusu hasarların aniden ortaya çıkması önlenebilmektedir. Diğer taraftan tasarım sürecinde yorulma performansının belirlenmesinde, yetersiz bilgilerden ve genellemelerden kaynaklanan bazı belirsizlikler söz konudur. Bu çalışmada, kırılma mekaniğine dayalı yorulma çatlak büyümesi tahmininde yer alan, malzeme, yük ve geometri parametrelerindeki belirsizliklerin etkileri Interval Analizi Yöntemini (Aralık Sayılar) kullanılarak sunulmuştur. Dolayısıyla, farklı türden parametrelerin belirsizlikleri dikkate alınarak, FCG life için alt ve üst sınırları ile belirlenmiş güvenli aralık değerlerin elde edilmesi hedeflenmektedir. Önerilen yöntem, EN-GJS-600-3 malzeme özelliklerine sahip bir plakanın yorulma çatlağı büyüme ömrünün tahminine uygulanmıştır. Matematiksel işlemlerde MatLab ara yüzü için geliştirilen interval toolboxlar kullanılarak, interval aritmetiğine özgün olarak hazırlanan bilgisayar kodu ile birlikte çalışması sağlanmıştır.

Anahtar Kelimeler:

Yorulma, FCG, belirsizlik, interval analizi, Paris kanunu

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