Question

A helical compression spring has 14 active coils and the free length is 12.5in. The outside diameter is 7/16 in and the spring has squared and ground ends. The end plates are constrained to be parallel. The material is music wire with presetting. The wire diameter is 0.042 in. Determine: (1) for static conditions compute the spring index, the solid length, the stress when the spring is compressed to the solid length. Check if static yielding occurs while the spring is brought to its solid length; (2) for dynamic conditions with Pmin=0.9 lb and Pmax=2.9 lb, check if the spring experiences torsional endurance limit fatigue torsional yielding, or torsional fatigue failure. Assume a survival probability of 90%, unpeened coil, and fatigue failure based on 50x103 cycles

Answer 1