Examples of Vibrations due to a stranded rope running over pulleys and the chosen solution
According to the current state of art, in order to reduce the amplitude of acceleration induced into the structure (like tower or elements of the terminal stations) when a stranded rope is running over a sheave-battery, adjustments have to be made to the geometrical parameters of the sheave-battery as well as to the relation between the rope lay length and the distance between two adjacent sheaves. Yet, the initial cause of the vibration (the helical rope-surface) is accepted without question. It is important to point out here, that adjustments made as described above, will be valid for only one specific wire rope (one certain lay length). Any change in lay length occurring during service for whatever reason will destroy the condition achieved. This paper presents a reliable method to prevent vibration induced in adjacent structures by means of a stranded rope with an almost cylindrical surface – the source of the vibration is hereby virtually eliminated. During the development of this product care has been taken, that all the properties necessary in a stranded rope such as splicability, non-destructive-testability, durability etc. either improve or are at least maintained at the current levels. This new stranded rope design is also suitable in applications where single fixed sheaves are used in a vibration-sensitive structure.
Author(s): Kopanakis, G.