Açık hücreli metal köpüklerde hücre sayısının ve anizotropinin enerji absorbe etme verimliliği üzerine etkisi

Açık hücreli metal köpükler hücresel yapısı sayesinde hem hafif malzeme olarak kullanılabilir hem de darbe enerjisini etkin bir şekilde sönümleyebilir. Bu çalışmada 30 ve 45 ppi (inç başına gözenek sayısı) metal köpük içerisinde bulunan hücre sayısının ve anizotropinin enerji sönümleme verimi üzerine etkisi kuazi-statik basma deneyleriyle araştırılmıştır. Bu çalışmaya göre aynı boyuttaki köpüklerde hücre sayısının azalmasıyla mukavemet düşmektedir. Fakat enerji sönümleme verimliliği hücre sayısının azalmasıyla yükselmektedir. Bunun sebebi hücre boşlukları hücre büyüklüğünün artmasıyla artar böylece hücreler daha az sertleşmeyle deforme olmaktadır. Metal köpüğün yüklenme doğrultusunun enerji sönümleme verimliliği üzerine etkisi bulunamamıştır. Küboid köpük parçaların küp şeklindeki parçalara nazaran daha yüksek mukavemet gösterdiği bulunmuştur bu da deformasyon konsantrasyonu ile açıklanabilir.

Anahtar Kelimeler:

Metal köpükler, Basma deneyi, Verimlilik, Sertleştirme

Effects of the cell number and anisotropy in the open cell metal foams on the energy absorption efficiency

By means of cellular structure, open cell metal foams can be used as a light-weight material, and they can absorb impact energy effectively. In this study, effects of cell number and anisotropy in 30 and 45 ppi (pores per inch) foams on the energy absorption efficiency are investigated by quasi-static compression tests. According to current study, strength of foams decreases with lowering the number of cells for the same foam dimensions. However, energy absorption efficiency increases with decreasing number of cells. The reason for this is the enlarging of cell voids with increasing cell size; therefore, cells deform with less hardening. Effects of loading direction of metal foams on the energy absorption efficiency could not be found. It was observed that the cuboid foam samples exhibited larger strength as compared to the cubic foam samples, and this could be expressed by deformation concentrations.

Keywords:

Metal foams, Compression testing, Efficiency, Hardening,

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