Influence of moisture on functional properties of climbing ropes

摘要

Recently developed experimental-numencal-analytical (ENA) methodology presented in Ref. [13] by Emri et al. based on a simple non-standard falling weight experiment, was used for mechanical characterization of "dry" and "wet" climbing ropes. Analysis of the maximum impact force; the visco-plastic component of rope deformation; the amount of stored, retrieved and dissipated energy; the stiffness of the rope; and the maximum value of the first derivative of the de-acceleration 0°'t) showed that moisture significantly affects the functionality and durability of ropes. "Wet" ropes create larger maximum force, dissipate less energy, and generate larger retrieved energy that propels climbers in the opposite vertical direction. Properties of "wet" ropes are also more sensitive to number of repeated drops. Major changes of all physical quantities are, as a rule, observed during the first three to four drops. It has been shown that for the safety of climbers the most indicative properties are dissipated energy and jolt (first derivative of climber de-acceleration). The ratio of dissipated and retrieved energy, ip = Wdys/Wret, could be used as a criterion for evaluation of the quality of climbing ropes.