Forensic Techniques for Investigating the Causes of Fiber Rope Failures

This paper discusses techniques that are used to determine the underlying causes of fiber rope failures. Rope failures can exhibit a complex mixture of features that are sometimes difficult to interpret and understand. It is necessary to distinguish between those features which occurred during or after a failure from those that may have caused or contributed to it and this requires both judgement and experience. An investigation always starts with a visual examination and preliminary unravelling of the fail zones of the rope. Selective tensile testing is then used to generate data that can be used to estimate the rope strength at the time of fail. If necessary, further techniques such as optical and scanning electron microscopy are used to provide additional information for a more detailed understanding of a failure. Thermal stability and UV resistance may also have to be assessed when investigating failures of certain types of rope and techniques for doing these investigations are also described. As with any type of forensic investigation, the objective must be to gather as much information as possible, from as many different perspectives as possible, to permit the correct conclusion to be drawn as to the cause or causes of any rope failure. Examples from several fiber rope failure investigations are discussed in the paper.