Unformatted text preview: wires gradually show wear and breaks; such ropes should be retired. Periodic in-spections prevent fatigue failures by parting of the rope. 17-30 Since this is a design task, a decision set is useful. A priori decisions • Function: load, height, acceleration, velocity, life goal • Design Factor: n d • Material: IPS, PS, MPS or other • Rope: Lay, number of strands, number of wires per strand Decision variables: • Nominal wire size: d • Number of load-supporting wires: m From experience with Prob. 17-29, a 1-in diameter rope is not likely to have much of a life, so approach the problem with the d and m decisions open. Function : 5000 lbf load, 90 foot lift, acceleration = 4 ft/s 2 , velocity = 2 ft/s, life goal = 10 5 cycles Design Factor : n d = 2 Material : IPS Rope : Regular lay, 1-in plow-steel 6 × 19 hoisting...
View Full Document
- Fall '11
- Mechanical Engineering, Wire, 1-in diameter rope, wire rope analysis