Testing of a Wire Rope

Initially, a load deformation curve was obtained experimentally for a 1.306-in. diameter, 6 × 19 Seale IWRC rope on a 600,000-lb testing machine. A plot of the load as a function of the deformation is shown in Figure 6.1. In this test, a 45-in. gage length was used and the total cross-sectional area ΣπR2 _i = 0.727 in.2. The experimental effective modulus of the rope is about 18,400,000 psi, although the preceding theory predicts an effective modulus, based on E = 29,000,000 psi, of about 0.7 × E = 20,300,000 psi. The theoretically determined modulus is higher than the experimentally determined one, since contact deformation between the wires is neglected; also, the outer strands tend to settle inside the radius of the IWRC, since the line load on the outer strand acts only at the contact points. This last condition is especially apparent in the initial loading of a rope. In the above theory it was assumed that the modulus of elasticity of the wire material was 29,000,000 psi.