Volume 16, Issue 2 (March 1988)
Localized Intrinsic Strengthening Approach (LISA): A Practical Method for Determining the Tensile Strength of Multistrand Cables
The problem of stress concentration and the associated premature failure in tension test specimens of multistrand conductors and wire ropes has been overcome through localized cooling of the end fitting with liquid nitrogen. A reliable measurement of the true tensile strength (TTS) of a range of multistrand bodies of interest to electrical utilities has been achieved using a number of commercially available end fittings and clamps. Measured values of TTS have been found to be as much as 22.9% higher than the calculated rated tensile strength (RTS). A standard test method is proposed that is simple and cost effective. The localized intrinsic strengthening approach (LISA) is invaluable in a quantitative evaluation of the efficiency of end fittings and splices, in determining the residual strength of multistrand bodies, and for optimizing the design of conductors and wire ropes.