Failure of wire rope sockets under impact loading

Abstract

Wire ropes are used world wide for various applications. However all sizes and types of construction require an effective method for attaching the ropes to other structures. One popular termination technique, particularly for larger diameter ropes, consists of using a steel conical socket into which a polyester resin mix is poured, creating a joint which secures the individual wires of the rope. The UK Health and Safety Laboratory were contracted by the UK Health and Safety Executive - Offshore Safety Division to carry out a series of large scale impact tests on 25mm compacted stranded wire rope (this rope size is commonly used for offshore cranes and diving bell handling equipment) to determine if rope's performance was affected by strain rate. It was noted early in the testing programme that under dynamic loading, the rope socket often failed, whilst under static loading the wire rope always failed. The experimental data showed that the force and energy absorbed when the socket failed was considerably lower than the minimum specified for the wire rope. This has particular significance for the offshore industry where the launch/recovery of diving bells often results in large dynamic forces being applied to the rope and ancillary equipment.