Redesigned bonded fasteners enable RTM railway cabinets

Adhesion Technologies Ltd. (ATL, Hampshire, UK) has developed a range of in-mold bonded fasteners, which reduce build time by eliminating the need for hole-drilling. Designed by composite engineers in conjunction with Southampton University and the UK government-funded Farnborough Aerospace Consortium, ATL’s patented products comprise more than 2,000 variants, including manganese-boron alloy, 316L stainless steel and thermoplastics as well as a castellated base option, which boosts torsional strength by 24%. Trademarked Spida Fixings, these fasteners have been designed to dissipate stress in composite structures, can be epoxy-coated to reduce risk of galvanic corrosion and are used in composite structures made via vacuum.

Recently, ATL was approached by a leading industrial composites manufacturer in the UK that developed
a composite solution for railway trackside control cabinets. Although these electronics enclosures are traditionally metal, they are now benefitting from composites’ improved resistance to corrosion, vibra- tion and vandalism/theft, as well as insulation against electrical conductivity. The cabinet brought to ATL weighs 1,000 kg fully assembled and features a one-piece structural roof made by RTM. Such cabinets are typically relocated multiple times throughout their lives using a crane. The crane lifts the cabinet by chain hooks connected to four removable 12-mm threaded eyebolts in the roof. Unfortunately, the fasteners for the eyebolts were separating at the interface between the nut and the perforated, welded base.