Impact behaviour of bonded built up beams: experimental results

The use of the structural adhesives represents an interesting alternative with respect to spot welding in the construction of built-up beams. An essential aspect for these elements is the capability of absorbing energy in the axial collapse mode caused by an impact. The work examines four different solutions for the beam geometry, three of which are taken from the standard cross sections obtained by welding whilst the fourth is designed to be adhesively bonded. Each type of section has been tested under four different loading conditions, namely static crushing, medium velocity crushing, and impact at two different velocity values. The results show that the behaviour of the beams manufactured with this technique is good, provided that the shape of the cross sectional does not induce peeling in the joints. The best performance is obtained if bonding is carried out on planes coinciding with the sides of the section and not with the flanges.