Determination of design mechanical properties of adhesives in a tensile and compression test

Structural adhesives are increasingly used in the construction of mechanical devices. Adhesive joints replace welded, soldered and other joints. The strength of the adhesive joints obtained allows the transfer of loads. The possibility of combining different materials is a significant advantage. In order to design joints, it is necessary to know the mechanical properties of adhesives. Determining them requires the use of special methods of obtaining specimens. Analytical and numerical methods of stress estimation in adhesive joints require more material data than is provided by manufacturers. The aim of the following work is to present the method of manufacturing specimens and to compare methods for determining mechanical properties based on three example structural adhesives. The paper presents two methods for determining the mechanical properties of exemplary structural adhesives: metacryl, epoxy and polyurethane adhesive. The tests were carried out on a cast and then machined specimens. Flat specimens were used in a tensile test. In compression test, round specimens were used. The results obtained from both tests were compared with the manufacturer's data. Differences and possible reasons for them were indicated. Stress distributions in the adhesive single lap joint were estimated using the Volkersen analytical method for various determined mechanical properties.