A constitutive equation for the behaviour of a mountaineering rope under stretching during a climber's fall

Leader fall is the main concern in climbing activities and the appropriate answer to the problem is the rope. An accurate numerical simulation of the consequences of a fall on the "safety chain" (assembly of rope, fixed points, karabiners, cords and other climbing gears) is essential for understanding the events and conceiving safety methods. It also reduces the times and costs involved in experimental assessments. In this context a sound knowledge of the rope properties is essential. The analytical model of the rope behaviour during stretching should be slim enough to reduce computing time, but still be able to describe the rope behaviour in each segment of the "safety chain". The present paper proposes a model to describe the rope behaviour when stretched, representing the force as a function of strain and strain rate. Model parameters have been calibrated on experimental data measured from a specific mountaineering commercial rope. The same procedure can be applied for different mountaineering ropes present on the market. (C) 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11