Exam. 2-B	Machine Elements Design
Student Name:		Student No.

1) A- Define the following (3 only +):

a- Spring index:

b- Coil spring mean diameter:

c- Wahl factor:

d- Spring maximum deflection:

1) B- Write the types of springs:

	Type of spring	Uses
1
2
3

1) C- If k₁ = 700 N/mm, k₂ = 400 N/mm, k₃ = 200 N/mm

+ i- Which one will have more defliction under the same load?

ii- Find the equevlant spring rate in the figure shown:

iii- What is the deflection of the springs in the figure under a load of  1100 N

2) A helical compression spring has a mean spring diameter D of 120 mm.

i- If the allowable shear stress due to torsion only on the spring is 300 MPa, when a load P₁ = 4000 N is applied to it. Find the spring wire diameter d.

+ ii- Find the spring index C, and the Wahl factor K_w, and solid length L_s if the total number of turns is 10, and the ends are plain.

iii- Find the total stress due to a maximum load P₂ of 5000 N for the same spring.

iv- Check the stress using the nomogram, for case iii.      

4) The 4,000 N force is applied to M8 setscrew. If the required safety factor is 2, decide on the suitable material for the setscrew.