Bonding analysis of carbon/epoxy composites with viscoelastic acrylic adhesive

This paper focuses on the analysis of viscoelastic bonding strength of carbon/epoxy laminates with different surface treatments. Bonding is a well known technique, and is widely used in many industrial applications. Rigid bonding aims at transferring structural and vibration loads from one laminate to the other. The use of dissipative bonding material also helps reducing structural vibrations in many key applications. In this work, the bonding strength of carbon/epoxy substrates with viscoelastic acrylic adhesive was measured by means of a wedge test. The surface finish, which plays an important role in bonding, was characterized using a surface profiler and the OnduloMD system. Surface roughness and concentration of surface porosities were measured to define the quality of the laminate surface. It is shown that the final crack length decreases with increasing wedge penetration rate and increasing density of surface porosities. The surface pre-treatment with primer also reduces crack length, and thus increases fracture energy. The fracture energy ranges between 300 J/m2 and 3000 J/m2. The proportion of this energy which is due to dissipation in the adhesive, increases with the wedge penetration rate and reaches up to 60% of the total fracture energy.