EXAMINATION OF THE TIME-DEPENDENT BEHAVIOUR OF CLIMBING ROPES UNDER IMPACT LOADING

A recently developed experimental-numerical-analytical methodology, based on a simple non-standard falling weight experiment, allows the calculation of several physical quantities that are important for the safety of a climber, such as: the maximum force acting on the rope; jolt, i.e., the derivative of the (de) acceleration; the maximum deformation of the rope; and modification of the stiffness of the rope within each loading cycle. This methodology was used in the mechanical characterisation of three commercial climbing ropes. The results indicate that ropes which according to the existing UIAA standard belong to the same quality class actually exhibit significantly different behaviour when exposed to the same loading conditions. One of the tested ropes exceeded the critical jolt value (120g/s) already during the second fall. Thus, although it satisfies the requirements of the EN 892 standard, this rope may not be considered safe. The results prove that the existing safety standards need to be reconsidered.