Enhancement of Shear Strength in Lap Joints with Different Surface Patterns

Abstract

In this study, surface patterning with CNC vertical machining center was applied to aluminum surface for the enhancement of the shear strength of the epoxy bonded lap joints. It was found that the pattern shape affected shear strength and among vertical, square, horizontal, 45 degree and diamond patterns, 45 degree provided the highest shear strength of 24.6 MPa. Moreover, the pattern features also affected the shear strength. Decrease in the depth led to slightly lower shear strength, whereas increase in the depth gave slight enhancement. The optimum depth was found as 300 μm and the obtained shear strength was calculated as 25.5 MPa. Additionally, increase in the width length led to lower shear strength. On the other hand, decrease in the width length provided higher shear strength. The increment became smaller as the width length increased. Also, after a point, the trend reversed and the shear strength decrease slightly. The optimum width length and the corresponding shear strength were found as 1.0 mm and 28.0 MPa, respectively.

Keywords

• Shear strength
• Epoxy
• Lap joint
• Surface pattern
• CNC

Farklı Yüzey Desenli Bindirmeli Bağlantılarda Kesme Mukavemetinin İyileştirilmesi

Öz

Bu çalışmada, epoksi ile bağlanmış bindirmeli bağlantıların kayma mukavemetinin arttırılması amacıyla, alüminyum yüzeylere CNC ile yüzey desenleme işlemi uygulanmıştır. İşleme şeklinin kayma mukavemetini etkilediği görülmüş ve dikey, kare, yatay, 45 derece ve baklava şekillerinden 45 derece şeklinin 24,6 MPa ile en yüksek mukavemeti verdiği gözlenmiştir. Ayrıca şekil özelliklerinin de mukavemeti etkilediği anlaşılmıştır. Derinlikteki azalma daha düşük kayma mukavemetine yol açarken, artma ise daha yüksek değerler sağlamıştır. Optimum derinlik 300 μm olarak bulunmuş ve elde edilen kayma mukavemeti 24,6 MPa olarak hesaplanmıştır. Bunların yanı sıra, şekil genişliğinin artması daha düşük mukavemete yol açmıştır. Diğer yandan genişliğin azalması ise daha yüksek mukavemet sağlamıştır. Ayrıca, bir noktadan sonra trend tersine dönmüş ve mukavemette azalma gözlenmiştir. Optimum genişlik ve sağladığı kayma mukavemeti sırasıyla 1,0 mm ve 28,0 MPa olarak bulunmuştur.

Anahtar Kelimeler

• Kesme mukavemeti
• Epoksi
• Bindirmeli bağlantı
• Yüzey deseni
• CNC

Kaynakça

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