Part -1:

Design a helical compression spring to exert a force of 25 to 35 lb when compressed to a length of 2.5 to 2.0 inches (operating length). When its length is 3 or 4 inches (installed length), it must exert a force of 10 lb. The spring will be cycled rapidly, with severe service required. Use ASTM A227 Steel wire.

Use design methods 1 and 2, and along with a spreadsheet for each method, make a table showing: D_w, D_m, D_o, D_i, cc and L_f for each method.

Part -2:

Spring Design (HELICAL EXTENSION)

Design a helical extension spring to be installed on the storm door of a residence. When the door is closed, the spring must exert a force of 15 to20 lb at a length between attachment points of 10 to 12 inches. As the door is opened, the spring is pulled to a length of 18 inches with a maximum force of 30 lb. An outside diameter of %, in (0.75 in) is desired. The door will be cycled about 20 to 25 times per day. The design stress should be based on average service. Use ASTM A401 Steel wire. Show the final configuration of the end loops, i.e. show complete analysis for stress.

Part -3:

Design a helical torsion spring for average service using ASTM A228 Music Wire. The spring will exert a torque of 1.5 lb-in after a deflection of 180° from the free condition. The outside diameter of the coil should be no more than 0.45 inches. Specify the diameter of a rod on which to mount the spring.