SAE ARP 6881:2018 pdf free
SAE ARP 6881:2018 pdf free.Guidelines for the Use and Installation of Bonded Cable Harness Supports
Although there are significant benefits to the use of adhesive bonded studs, standoffs, and cable tie mounts for wring applications, there is also a legitimate concern about the strength of the adhesive bonded fastener. The adhesive bonding is process dependent, and requires good adhesive selection, mixing, and application, as well as good surface preparation of the bonding surfaces. For that reason, training mechanics in proper adhesive bonding techniques is a key to successful use of adhesive bonded fasteners in aerospace applications. In most cases, with proper adhesive selection and surface preparation, the strength of adhesive bonded cable tie mounts can exceed the strength of the nylon zip ties that are used to attach the wiring to the adhesive bonded cable tie mount. For adhesive bonded cable tie mounts, the strength is such that adhesive failures are extremely rare; typically, if nylon zip ties are replaced by stainless steel wire ties, then the failure mode is usually a mechanical failure of the adhesive bonded cable tie mount. For adhesive bonded studs or standoffs used to attach p-clamps, the strength capabilities of these adhesive bonded studs and standoffs are even greater than for adhesive bonded cable tie mounts; however, overloading may be more likely, since the length of the stud or standoff may allow for a significant moment- arm making peel failures (or cleavage failures) more likely. In any case, the most likely cause for well-installed adhesive bonded fasteners is over-loading or abuse (bumping, kicking, or stepping on the adhesive bonded fastener, or pulling on, hanging from, or stepping on the wiring attached by adhesive bonded fasteners).
One final concern is environmental exposure of adhesives or sealants to aerospace fluids (aviation fuels, hydraulic fluids,de-icing fluids, corrosion protective coating, etc.) or stresses such as extreme temperatures and changes, vibration, and high G-loads. Adhesive bonding has a long history in aerospace applications and it is critical that adhesives specifically qualified for aerospace applications be used and the appropriate adhesive be selected for the intended application. Selected adhesives need to have documented temperature ranges matching expected application temperature ranges, and resistance to typical aerospace fluids. Applying a sealant over the adhesive fllet and/or painting the entire adhesive bonded part is an effective method of providing additional protection to the adhesive attaching the adhesive bonded fastener.SAE ARP 6881 pdf free download.
