Modeling the Performance of Horizontal Anchor Lines during Fall Arrest

摘要

The basic materials used for the construction of anchor lines for personal equipment protection against falls from a height are ropes and textile webbing. During fall arrest, horizontal anchor lines significantly affect the forces acting on the worker and the work site elements, as well as the fall arrest distance. Manufacturers of the equipment are required to estimate those parameters for various conditions of use by numerical simulations with a validated model. The model discussed in this paper reflects the mechanical structure of the line (whether singles-span or multi-span) taking into account Maxwell's and Kelvin-Voigt's non-linear rheological models for viscoelastic materials. The model consists of a system of seven non-linear differential equations with the parameters describing static load-elongation characteristics and time-courses of dynamic loading forces for selected ropes and textile webbing. The numerical model developed was used to simulate the performance of horizontal anchor lines of different constructions. The model was validated by comparing the numerical calculations with laboratory test results and was shown to be sufficiently accurate to be used for designing fall protection equipment.