What does a knot in a lanyard do to its overall strength?

What does a knot in a lanyard do to its overall strength?

• A. Reduces strength by 10%
• B. Reduces strength by 50%
• C. Reduces strength by 25%
• D. No change in strength

Answer: (B)

Knots create stress concentrations that significantly weaken a rope. When a lanyard is tied into a knot, the fibers are bent, crushed, and rubbed as load is concentrated in a small, irregular area. This disrupts the uniform distribution of force along the rope and introduces points where failure is more likely to start. In practical terms for safety gear like lanyards, tying a knot typically reduces the rope’s usable strength by about half. That means you should not rely on the rope’s full nominal strength when a knot is present. While the exact reduction can vary with knot type and rope construction, a roughly 50% decrease is the common guideline used for planning and safety margins. The other options underestimate the effect or ignore the impact of the knot on load distribution.

Knots create stress concentrations that significantly weaken a rope. When a lanyard is tied into a knot, the fibers are bent, crushed, and rubbed as load is concentrated in a small, irregular area. This disrupts the uniform distribution of force along the rope and introduces points where failure is more likely to start. In practical terms for safety gear like lanyards, tying a knot typically reduces the rope’s usable strength by about half. That means you should not rely on the rope’s full nominal strength when a knot is present. While the exact reduction can vary with knot type and rope construction, a roughly 50% decrease is the common guideline used for planning and safety margins. The other options underestimate the effect or ignore the impact of the knot on load distribution.