Glued composite studs best for aluminium foam

Tom Shelley reports on a fastener suited for light-weight structures

Light-weight structures made of aluminium foam panels are normally joined using standoff studs, usually made of aluminium and welded to the panels. Moulded composite studs attached using adhesive yield a number of advantages in such constructions, however. Studs moulded out of PEEK reinforced with glass or carbon fibre and made by the Swiss company, Icotec, weigh only 0.9g each. The show no corrosion, even in aggressive environments and offer improved fatigue resistance. In addition, they show an improved failure mode. Tests presented at the 2nd Böllhoff Fachkolloquium by Dr. Ing Get Ahlers-Hestermann showed that in the case of welded aluminium studs, axial tensile tests resulted in the tearing of the cover sheet of the aluminium foam panel at 1700N. The cover sheet was ripped out around the welded part of the stud. Composite standoff studs were also pulled and torn off at 1700N. The difference was that the stud and the panel both remained intact and only the adhesive bond failed. The diameter of the composite stud's base is 20mm as compared with that of the aluminium stud which is 9mm. Icotec Icotec