WIRE ROPE INSPECTION – THEORETICAL FOUNDATIONS.
In order to be useful, rope retirement criteria must meet several conditions:
- They must conform to the cardinal principle that
- a rope’s strength must be greater than its maximum possible load stress over its entire life.
- They must be quantitative.
- They must be geared to the inspection methods used.
These and related issues are discussed in my paper titled “Wire Rope Nondestructive Evaluation (NDE) Procedures, Retirement Criteria and Lifetime Prediction Methods – Rope Usage and Rope Condition Monitoring (RUM/RCM)”.
The paper presents a comprehensive theoretical and critical review of wire rope inspection methods and associated issues. These theoretical considerations have been confirmed by numerous experiments.
Unfortunately, standards like “ISO 4309:2017, Cranes — Wire ropes — Care and maintenance, inspection and discard” are presently not very useful. For example, ISO 4309 formulates MRT retirement criteria by mixing up incompatible concepts that apply to either visual or to MRT inspections, respectively. This misconception is confusing and can potentially lead to dangerous misinterpretations!