Investigation of the thermal strain behaviour of bonded joints in a cryogenic environment

Low temperatures up to the cryogenic range represent an increasingly relevant area of application both in space travel, in the transport and storage of liquid gases and in the field of research (e.g. superconductivity). Adhesive bonding is a predestined joining method for joints in these applications. However, the material behaviour of adhesives and in particular the mechanical behaviour of bonded joints at cryogenic temperatures has been little researched. This paper compares the tensile and shear strengths of adhesives and bonded specimens at room temperature and cryogenic temperature and also investigates the strains occurring within the bonded joint. An increase in strength of up to 35% at a temperature of 77 K is found for tensile shear specimens. For tensile specimens, the increase is up to 347% due to embrittlement of the polymeric material. When examining the strains, the largest resulting contractions are found to be up to 0.6% at the interface between the adhesive and the joined part due to different expansion coefficients of the materials.