Influence of Planar Discontinuities on the Sheet Adhesive Joint Strength

Over the years, prediction of adhesive joint strength has attracted much attention in the scientific and industrial research. In this research, the influence of planar discontinuities on the sheet adhesive joint strength was examined. The aim of this study is an investigation of the size and shape effects of the two-dimensional defects on the ultimate strength of adhesive joints. Therefore, defects in two-dimensional geometry, including rectangular, triangular and circular shapes and with dimensions of 5, 10, 15 and 20 mm are made in the overlap zone in the single lap joint using of two-component Araldite 2015 adhesive. The defective samples are based on standard test ASTM D1002-01 and maximum load is achieved. Generally, regarding to defects with a size of 10 mm, the circular samples are most withstand forces and the triangular and rectangular samples are in the next places, respectively. But for samples with defects size 15 mm, samples by triangular, rectangular and circular defects carry out the maximum load, respectively. For defects with a size of 20 mm, the rectangular and circular samples tolerate the same load approximately and the triangular sample has less able to withstand the force. Finally, based on the experimental results, correction coefficients are proposed to predict the strength of defective samples.