On the Mechanical Interactions in Suspension Rope – Sheave / Pulley Systems

Steel wire ropes employed as suspension means in lift systems are subjected to bending when passing around rigid traction sheaves/pulleys. In this paper, a suspension rope is represented as a moving Euler-Bernoulli beam and its global mechanical behaviour and interactions at the contact area are described by a nonlinear Boundary Value Problem with an unknown boundary. The problem is solved numerically for a lift system with the car suspension in a 2:1 roping configuration. The solution yields the curvature values, slope angles and the distribution of tensile and bending stresses along the rope span. It is demonstrated that the boundary angles vary during the lift travel and the distribution of stresses over the transition arc is nonuniform.