Effect of the interfacial stress distribution on the material interfacial shear strength measurement

The interfacial strength is a very important material property for composite materials and other hybrid materials with different stress distributions. Will the interfacial stress distribution have a significant effect on the interfacial strength measurement?

To better understand this question we carry out an integrated experimental and numerical analysis to study the interfacial shear strength of bonded materials. Two types of shear tests, namely the Iosipescu shear test, and the short-beam shear test are employed. We find the measured average shear strengths to be very close, even though the interfacial shear stress distributions of these two kinds of specimens are very different. Therefore, the interfacial stress distribution has the least effect on the interfacial strength measurement if the interfacial shear stress is non-singular. Our results have been published in Experimental Mechanics (pdf). We utilize one optical technique to obtain fringe patterns, and successfully replicate these using finite elements to validate our model. One such comparison for a short-beam shear specimen is presented here.