Sample Exam 2

Machine Elements Design

SE2

Student Name:

Student No.

 

1) Define the following:

 

a- Coil spring mean diameter D:

 

b- Spring buckling:

d- Stress of solid torsion bar under torque T:

 

 

1) B- Write the types of coil spring wire stresses:

 

Stress type

1

 

2

 

3

 


1) C- If k1 = 1000 N/mm, k2 = 500 N/mm

i- Show; which one of the spring configurations will have a greater spring rate?

 

 

 

                                                                                            

iii- What is the deflection of the spring number 1 if the spring load is  1000 N

 

 

 

 

2- A coil spring has the following data:

- mean coil diameter D = 150 mm

- wire diameter d = 15 mm

- number of total coils is 10

- ends of the spring are squared and ground

- the shear modulus of the spring material G = 81400 MPa

- the free length of the spring Lf = 360 mm

Find:

a) the spring index C

b) the Wahl factor Kw

c) the maximum stress on the spring due to load P = 4000 N

d) the solid length Ls

e) the deflection δ under the load P

f) the maximum deflection δmax of the spring

g) the spring inside coil diameter Di

h) check the stress of the spring using the nomogram using: D, d, P, C

 

 

 

 

 

 

 

 

3- a) Find the reactions at point A and B from the figure shown.

 

 

 

 

 

 

 

 

 

 

 

 

b) If the spring is replaced by a leaf spring where 2F = 4000 N, 2L = 1000 mm, number of leaves (n) = 4, leaf width (bí) = 50 mm, leaf height (h)= 9 mm.

Find the stress on the spring (σb).