Steel Wire Rope (SWR) constructions are still the main components used as media for a large portfolio of traction elevators. The mechanical design of SWR is defined by the steel material and the complex geometry, which can be described as a space helix layered structure.

This design defines the characteristics which are fundamental to achieve the operational requirement of elevators. Essential characteristics are the minimal breaking force, the static and dynamic elongation and the number of bending cycles projected prior reaching the discard criteria.

In this paper we are focusing on the dynamic elongation of a SWR and particular about the change of the dynamic elongation of a SWR over the lifetime.

Thanks to mathematical models the deformation and elongation of wire rope under known tension can be calculated, in addition the elastic modulus of a steel rod is well defined and the definition of the elastic modulus of a rope is determined according to the ISO standard 12076.

In the practical use of SWR where several ropes are bearing the load together, there are many imperfections and influencing factors leading to a change of the dynamic elongation. This paper identifies, explains, and describes the impact of such factors.

The identification is based mainly on observation and sample measurements in real lift installations, so the impact is illustrated in a qualitative (not exact quantitative) way, using the stress-strain diagram. Since the cause of the influencing factors are identified, also corresponding mitigation measures are explained.

Ultimately when applying this mitigation measures, the deviation to the initial rope design and purpose to fulfill the operational requirement of the elevator can be minimized.

With this, the rope and rope system can stay longer within the range of the required performance, extend the lifetime, lead to longer replacement intervals, and reduce therefore the overall operating costs of elevators.