OTTIMIZZAZIONE DI GIUNTI IBRIDI HBB A DOPPIASOVRAPPOSIZIONE GFRP-ALLUMINIO

In order to exploit the advantages of both mechanical joints and adhesively bonded joints, in the lastyear a noticeable research activity has addressed to the so called hybrid joints (Hybrid Bonded Boltedjoint, HBB) that consist in combining a classical mechanical joint (bolted, riveted joint, etc..) to atraditional bonded joint or a co-cured joint.The present work shows the results of experimental and numerical analyses of double-lap HBB joints,carried out to detect the geometric configuration that permits to distribute the applied load between thetwo coexisting junctions and then to optimize their mechanical performance. The studied joint consistsof an internal adherent made by GFRP and external adherents made by aluminum type 2024-T6,connected by using an adhesive bonding and a M6 bolt. The optimization is detected by varyingvarious influence parameters such as the geometry of the lip and the shape of the washer, whichinfluences the distribution of the bolt preload.After the experimental tests, various numerical analyses are carried out to obtain a betterunderstanding of the static behavior of the joint, as well as to define reliable criteria for the strengthprediction under various operating conditions.