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














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 Kw, and solid length Ls 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.