Design and Mechanics of Multi-Lay Wire Strands

Wire strands and ropes have been used extensively for many years. However, the method for designing these elements remains highly dependent on the designer’s experience. In recent years, capabilities for the analysis of wire rope have progressed to a level where a reevaluation of wire rope design is appropriate. Recently, a linearized theory has been developed that allows a relatively simple method for analyzing complex strands and wire ropes. This theory, through substantiation with experiment, is felt to be reasonably accurate for most wire rope behavior. The present paper considers multi-lay wire strands and adds generality to the linearized theory to account for strands with any number and direction of wire lays. The geometry of wire strands is investigated in detail and a design methodology for strand geometry, including sizing the wires, is devised. The theory is then utilized to examine the effects of various design parameters on strand properties.