A rotation resistant wire rope has less safe working limit than an equal size 6×37 IWRC because?

A rotation resistant wire rope has less safe working limit than an equal size 6×37 IWRC because?

• A. Rotation resistance reduces breaking strength.
• B. Rotation resistance has no effect on safety requirements.
• C. It is primarily due to a higher coefficient of friction.
• D. IWRC has a higher breaking strength, and rotation resistant requires a higher safety factor.

Answer: (D)

The working load limit is determined by both the rope’s breaking strength and the safety factor applied in design. A 6×37 IWRC rope typically has a higher breaking strength and a robust independent core, which allows a higher WLL when the same safety factor is used. Rotation-resistant rope is designed to limit rotation under load, but its construction often yields a lower breaking strength and it also requires a higher safety factor to compensate for its geometry and how it behaves under bending and wear. So, when comparing equal sizes, the rotation-resistant rope ends up with a lower safe working limit because the higher breaking strength of the IWRC rope and the standard or lower safety factor used with it produce a higher WLL. The key points are that rotation resistance does not boost strength, and the safety factor for rotation-resistant rope is typically higher, reducing the WLL.

The working load limit is determined by both the rope’s breaking strength and the safety factor applied in design. A 6×37 IWRC rope typically has a higher breaking strength and a robust independent core, which allows a higher WLL when the same safety factor is used. Rotation-resistant rope is designed to limit rotation under load, but its construction often yields a lower breaking strength and it also requires a higher safety factor to compensate for its geometry and how it behaves under bending and wear. So, when comparing equal sizes, the rotation-resistant rope ends up with a lower safe working limit because the higher breaking strength of the IWRC rope and the standard or lower safety factor used with it produce a higher WLL. The key points are that rotation resistance does not boost strength, and the safety factor for rotation-resistant rope is typically higher, reducing the WLL.