An as-wound helical compression spring, made of music wire, has a wire size of 0.092in, an outer diameter of 9/16in, a free length of 43/8in, 21 active coils, and both ends squared and ground. the spring is unpeened. this spring is to be assembled with a preload of 5lbf and will operate with maximum load of 35lbf during use.
(a) estimate the factor of safety guarding against fatigue failure using a torsional Gerber fatigue failure critirion with Zimmerli date.
(b) Repeat part (a) using the sines torsional fatigue critirion (stready stree component has no effect). with zimmerli data.
(c) repeat using a torsional Goodman failure critirion with zimmerli data. (d0 estimate the critirion frequency of th spring.