ME 3305 MATERIALS’ SCIENCE

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1. Define properties of at least 3 different springs as indicated in the above table such as stiffness, modulus of rigidity, maximum shear stress, etc.
2. Discuss the results found and graphs. Classify the spring from the shape of the F vs δ curve.
3. Give some practical applications of helical spring.
4. Compare the properties of different springs and discuss their parameters accordingly. Which applications they are suitable for?

5. Why most of the helical springs have spring index between 4 and 12?
6. Solve the following problem A helical compression steel spring is subjected to an axial load of 1 kN. If the spring index is 6, number of turns is 15 and the maximum shearing stress in the spring is not to exceed 120 MPa, find the suitable wire diameter from the available wires of 12 mm to 18 mm with a step of 2 mm.

Determine the maximum shearing stress for the selected wire. Also determine the deflection and the spring constant. Modulus of rigidity for steel is 80 GPa. Use Wahl factor for stress concentration effect.