Mechanical characterization of adhesive layer using Double strap joint specimens

Abstract

In practical applications, most of our mechanical and civil structures are subjected to either oscillatory or static load. To design those structures, stress analysis is needed to withstand the design loads. In experimental stress analysis, strain gauges are mounted on those structures to determine stress at a point. Usually, strain gauges are mounted on the substrate using proper adhesives. The quality of strain data is a function of proper mounting. The thickness of adhesives used for mounting techniques should be optimum and very thin to ensure quality results. The underlying adhesive layer acts as an interface between the substrate and the strain gauge. This adhesive layer receives the maximum shear stress when the member is loaded in tension. Therefore, in this research work, the main focus is on characterizing the Araldite adhesive material. A tension test was conducted on the prepared bulk specimen to characterize the adhesive. The Double Strap Joint (DSJ) tests were conducted to investigate the interfacial shear strength and failure modes according to ASTM D 3528 standards. Two sets of specimens, such as plain and knurled straps, were used in this research work. The failure mode in the plain strap joint shows cohesive failure, and the knurled strap joint shows adhesive failure. © 2022