Fatigue Life of Stranded Hook-Up Wire

摘要

Hoop-up wires are exposed to three types of fatigue: (1) vibration; (2) sharp bending during installation, modification, and servicing; and (3) intentional flexing in service. As stated, vibration is very difficult to simulate in the laboratory. The second type, sharp installation-bending, is also difficult to reproduce because each installation and each installing activity have different wiring problems and technicians servicing equipment in the field subject the wires to varying degrees of abuse. When, as in the third case, a cable is required for flexing service, the application is usually known in advance so that laboratory procedures may be established which will accurately simulate the service use. In order to make laboratory studies of vibration and installation difficulties some sort of bending techniques must be resorted to in an attempt to evaluate the relative merits of wires and to compare constructions, materials, and installation techniques. This paper presents experimental data obtained for the purpose of solving such problems.