Characterization of adhesives at room and elevated temperatures

Abstract

Recent interest in advanced materials has paved the way for exploring joining options besides the traditional mechanical or thermal methods such as riveting or welding. Because of the availability of highly advanced materials, mass production rates and demands for more aesthetic products, adhesive bonding is being used in more applications. Today, interstate signs, semi-trailer panels, aircraft structures, and many other commonly used products are adhesively bonded. Some of the common misconceptions about adhesives are that they are inherently weak, require high operator skill, and are too expensive for production. However, these assumptions are true only when the adhesive joint design is faulty and/or the bonding process is performed incorrectly. This report includes testing, using single lap joints, of some adhesives both at room and elevated temperatures. Experimental setups for performing the tests are discussed. The shear strengths of various adhesives are determined with titanium adherents. A methodology was developed to determine the approximate value of shear modulus of the adhesive using finite element modeling (FEM) from the ASTM D 3165 test. This was completed in conjunction with experiments using a laser extensometer. Later in the report, correction factors that are used with the laser extensometer data to determine the shear moduli are determined.