Üç Nokta Eğilme Yüklemesi Altındaki Düşük Yoğunluklu Polimer Köpük Sandviç Yapıların Hasar Analizi

Bu çalışmada, örgü dokuma karbon/epoksi yüzeylere sahip, literatürde yer almayan, düşük yoğunluklu polimer köpük çekirdek sandviç kirişler, farklı uzunluk ve çekirdek kalınlıklarında üretilmiş üç nokta eğilme testlerine tabi tutulmuştur. Sandviç kirişlerin deneysel olarak eğilme davranışları incelenmiştir. Hem numune uzunluğunun hem de çekirdek kalınlığının etkisi ortaya çıkarılmıştır. Yüzey tabaka kalınlığının çekirdek kalınlığına oranı azaldıkça, yüzeyler arasındaki kayma kuvvetlerinin transferi azalmaktadır ve yüzeyler de zayıflamaktadır. Bu yüzden, hasar modu çekirdek kayması hasarından batma hasarına doğru değişmektedir ve sandviçler batma şeklindeki hasara uğramaya meyilli olmaktadır. Hasar modunu ve çökme kuvvetlerini tahmin etmek için literatürde mevcut bulunan teorik modellerden de faydalanılmıştır. Sonuçlar, hem analitik hesapların hem de deneysel bulguların birbirleriyle uyumlu olduğunu göstermiştir.

Anahtar Kelimeler:

Batma, Çekirdek kayması, Hasar modu, Sandviç yapılar, Üç nokta eğilme

Failure Analysis of Low-density Polymer Foam Core Sandwich Structures under Three-point Bending Loading

In this study, low-density polymer foam core sandwich beams, non-existent in the literature, having woven carbon/epoxy face sheets in different core thicknesses and specimen lengths were fabricated and then subjected to three-point bending tests. The bending behavior of the sandwich beams were scrutinized experimentally. The effects of both core thickness and specimen length were revealed. As the ratio of face sheet to core decreases, transferring of shear forces between the face sheets decreases and the face sheets also become weaker. Hence, the failure mode changes from core shearing to indentation and the sandwiches have become tendency to fail by indentation. The theoretical models available in the literature was also utilized to predict the failure mode and collapse forces. The results indicated that both analytical calculations and experimental findings are compatible with each other.

Keywords:

Core shear, Failure mode, Indentation, Sandwich structures, Three-point bending,

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