Machine Elements Design 
Exam 1 
Student Name: 
St. No. 
1 What are the differences and/or the relations between the following:
A
Stress (s), Strain (ε):
B
Moment (M), Torque (T):
C
Normal stress (σ), Shear stress (τ):
D
Second moment of area (I), Polar moment of area (J):
2 A structure suspended by EN3 tiebars is equivalent to a load of F = 120,000 N. The tiebars each have a diameter of d = 24 mm. If the SF is 9, calculate the minimum number of tiebars (n). 
3 Find the stress at point A due to the Forces shown in the figure.
Where: F_{x} = 100 N, F_{y} = 150 N, F_{z} = 200 N, L= 40 mm, H= 20 mm, d= 4 mm
A = ………………………..………
I = …………………………………
J = …………………………………..
F 
AT “A” 
Normal force 
Shear 
Moment 
Torque 
F_{x} 
Load 




Stress 





F_{y} 
Load 




Stress 





F_{z} 
Load 
X

F_{z} = 200 N

M = F_{z } L = 200 x 40 = 8000 N mm 
X

Stress 
X

τ_{z} = F_{z}/A = 200/ = 
σ_{b} = M y /I =  8000 x 2/ = 
X
