Question

A compression spring is needed to fit within a 1-in diameter hole. To allow for some clearance, the outside diameter of the spring is to be no larger than 0.9 in. To ensure a reasonable coil, use a spring index of 8. The spring is to be used in a machine by compressing it from a free length of 2 in to a solid length of 0.6667 in. The spring should have squared ends, and should be unpeened, and is to be made from music wire 1. Determine a suitable wire diameter, d, assuming that the OD 0.9 in 2. Determine a suitable total number of coil, Nt 3. Determine the spring constant, k 4. Determine the static factor of safety when compressed to solid length, ns 5. Determine the fatigue factor of safety when repeatedly cycled from free length to solid length. Use the Gerber-Zimmerli fatigue- failure criterion 1. The suitable wire diameter, d, is 2. The suitable total number of coil, N is 3. The spring constant, k, is 4. The static factor of safety when compressed to solid length, ns, is 5. The fatigue factor of safety when repeatedly cycled from free length to solid length is

Answer 1

Squaved en wire , ho find Suitable wise diametes we have う !d wave ends foo table, forngd Fron Squaswe 4 abadkenastvcs of the Ls= d(N.ti) leng tち Sowd

f飞吻table ,we have G = U-75 MPcf Spaing Comstant k Gdv (4 Spring force = Fs = KL Lo-Ls) 4c-2 408-3

2 utd ") te nsúl eSt engtちwe bave Aニ201 Kps İ.iv> yield stse04S(25047) Stabic factx of Safcty ns -sy 126.3 ns ,Spons is not Safe in thos Coydithue

= 0.5メ228 . 2) 4. 3S k psi , we get γ ." ToYSve w wodul.sof puptche s Pt Su 188,, epsi 3S 2 S Se

2メ2 8-3 IxigS.) Fotue factos of safety is C q 36.3 1413S O.322-6 So we 'Conclude that tち见Spao aaİSo under) . Saky. valus aove found above