Assessment of the creep life of adhesively bonded joints using the end notched flexure samples

The behavior of polymeric adhesives is time and temperature dependent, as they are considered viscoelastic materials. These materials can undergo creep deformation even at low stress levels and room temperature. This way, a viscous flow can occur at the adhesive layer and it can lead to viscous deformation, causing a modification in the adhesive properties. The current work aims to investigate the shear creep fracture energy of an epoxy adhesive using end notched flexure (ENF) samples creep tested until failure. The endurance creep limit for cracked bonded joints subjected to pure shear loading conditions is also investigated using ENF samples, representing the maximum creep load which ENF bonded joints can sustain without creep fracture after a specified time. The GIICr-life curve was obtained where the GIIcr is the mode II creep fracture energy. Results showed that small changes in creep load can significantly change the creep endurance limit. Creep fracture energy can be employed for joint design against creep service loads.