Optimal structural patterns of multi-strand wire ropes

Abstract

A quantitative approach for guiding the optimal structural design of multi-strand ropes with hierarchical helical structures has been developed. The structural pattern is optimized to maximize the capacity to bear axial loads and minimize the global toque of the rope simultaneously. In the light of the hierarchical calculation method for calculating the internal forces of wire ropes, a procedure of structural optimization is proposed for the multi-strand ropes. Two typical multi-strand wire ropes, namely 7 × 7 and 19 × 7 ropes, are treated in detail. The favorable structural patterns are identified, providing a database that covers most practical applications. It is demonstrated that the crisscross arrangement of strands or wires within the multi-strand ropes is beneficial for achieving a torque-balanced state. The influence of structural parameters on the global mechanical behavior of ropes increases gradually from inner strands to outer strands. The initial helix angle of the outer strands has a significant effect on the axial stiffness of the wire ropes.