Adhesively-bonded T-joint cohesive zone analysis using dual-adhesives

At the present time, adhesive joints are widely used in the industry, replacing mechanical and welding joints in many applications. T-joints are used in many applications such as automotive, marine, and aerospace industries. Several methodologies have been proposed to reduce the stress concentration at bonding ends and to obtain a more uniform stress distribution along the bondline, such as optimization of the overlap length (LO) or the adhesives’ thickness, adding outer or inner chamfers, using adhesive fillets, and dual-adhesives. Aiming to improve the strength of T-joints, in this work the dual-adhesive technique is studied, consisting of using two adhesives, placing a more flexible adhesive at the overlap ends and a stiffer one in the central area. To test this method in T-joints, different adhesive ratios were applied. To evaluate this concept, a numerical study was carried out using the cohesive zone modelling (CZM) technique, in the ABAQUS® software, including a study of failure modes, stresses, strength or maximum load (Pm) and dissipated energy (U). With the present work, it was initially possible to validate the CZM technique with experimental results. The numerical work that followed showed that the strength of T-joints significantly depends on the combination of adhesives used and that it is possible to achieve increases in Pm and U in relation to single-adhesive joints (SAJ).