Description

SAE AIR5464A – Metal Clad Fibers for Electrical Shielding and Harness Overbraid

Over the past two and one-half decades several metal clad fibers and fabrics have been developed to provide aerospace vehicle designers with a conductive, lighter weight alternative to coated copper, coated stainless steel and steel wire used for cable and wire shielding and harness overbraids on electrical cables. Several of these candidates have been unable to provide the strength or thermal stability necessary for the aerospace environment. However, several polymer-based products have shown remarkable resistance to the rigorous environment of aerospace vehicles.

Concurrent with these fiber developments, there have been changes in the structures of aerospace vehicles involving greater use of nonmetallic outer surfaces. This has resulted in a need for increased shielding of electrical cables which adds substantial weight to the vehicle. Thus, a lighter weight shielding material has become more critical to meet the performance requirements of the vehicle.

This report covers the properties of metal clad aramid fibers (MCAF), metal clad polybenzobisoxazole (PBO) fibers (MCPF), and metal clad liquid crystal polymer (LCP) fibers (MCLF), with test results when these products are used as a shield or harness overbraid and a listing of some of the known applications in the aerospace field. The use of these fibers as an electrical conductor in high strength tethers and other aerospace applications are new developments that show the versatility of MCF not only for weight savings, but also for applications where high strength and long flex life are required.