Fatigue Resistance of Large-Size Helically Corrugated Aluminum Sheathed Cables

Large-size corrugated aluminum sheathed cables are finding an increasing use in duct and manhole installations. The complex sheath geometry, relatively large conductors and increased insulation thickness, combined with restricted manholes, would lead to severe sheath strains, increasing the probability of sheath fatigue failure. The results of a program is presented for evaluating fatigue life of large-sized corrugated aluminum sheathed cables. A fatigue life curve is derived from axial fatigue tests on sine-type corrugated aluminum cable sheath specimens, the validity of which is checked by a fatigue test on a manhole model.