Solution Found!
A helical compression spring is wound using
Chapter 10, Problem 10.3(choose chapter or problem)
A helical compression spring is wound using 2.5-mm-diameter music wire. The spring has an outside diameter of 31 mm with plain ground ends, and 14 total coils. (a) Estimate the spring rate. (b) What force is needed to compress this spring to closure? (c) What should the free length be to ensure that when the spring is compressed solid the torsional stress does not exceed the yield strength? (d) Is there a possibility that the spring might buckle in service?
Questions & Answers
QUESTION:
A helical compression spring is wound using 2.5-mm-diameter music wire. The spring has an outside diameter of 31 mm with plain ground ends, and 14 total coils. (a) Estimate the spring rate. (b) What force is needed to compress this spring to closure? (c) What should the free length be to ensure that when the spring is compressed solid the torsional stress does not exceed the yield strength? (d) Is there a possibility that the spring might buckle in service?
ANSWER:a) The spring rate of the helical compression spring can be estimated using the spring index (C = D/d, where C is the spring index, D is the mean coil diameter, and d is the wire diameter). In this case, the spring index is 31 mm/2.5 mm = 12.4. Knowing the spring index, the spring rate in N/mm can be calculated using the formula k = (Gd4)/(8D3C4), where G is the modulus of rigidity and D and d are, respectively, the mean coil diameter and wire diameter. Estimating a modulus of rigidity, G,