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 ?m 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.