EXTENT AND CAUSE OF DETERIORATION OF NYLON MOUNTAIN CLIMBING ROPE

摘要

An analysis was made of 20 nylon mountain climbing ropes which had been in use for periods up to 18 years, to discover the extent and cause of deterioration in strength and energy-absorbing ability and changes in hardness and stiffness. It was found that loss in strength and energy-absorbing ability arise primarily from fiber abrasion which occurs at the surface of the rope. The nature of the rope construction is such that surface abrasion affects each of the three strands of the rope and all of the yarns in each strand except the few which constitute the so called "inner-core." There is no evidence that sunlight damage occurred to any significant extent in these ropes. The amount of abrasion, and loss of strength were directly related to the amount of use (not age) for those ropes that had more quantitative use histories. A Use Index (computed from the number of days of use) may be used to estimate rope deterioration. The extent of hardening and stiffening of the ropes was found to vary over a wide spectrum, but the causal factors were not determined.