Question

An as-wound helical-coil compression spring with infinite fatigue life is needed to resist a dynamic load that varies from 8.0 to 24.0 lbf at 45.0 Hz over a dynamic deflection of 0.3 in. Because of assembly considerations, the solid length of the spring cannot be more than 1.2 in. The spring should have squared and ground ends and is to be made from peened music wire. Upon closure, use a design factor of 1.2 guarding against yielding and a fractional overrun to closure x = 0.15. The fundamental critical frequency should be greater than 10 times the frequency of the dynamic load. The springmaker has the following wire sizes in stock: 0.059, 0.063, 0.072, 0.075, 0.085, and 0.090 in. Select a suitable spring with a fatigue design factor of 1.9 using the Goodman-Zimmerli fatigue failure criterion. Calculate the cost of the wire from which the spring is wound and use it as the figure of merit for your selection

Answer 1