Step No: 1

Use the following relation to calculate the inner diameter of the Steel pipe:

Here, the outer diameter is and thickness of the pipe is t.
Substitute 102 mm for  and 6 mm for .

Use the following relation to calculate the polar moment of inertia of the Steel pipe:

Substitute 102 mm for  and  for .

Step No: 2

Calculate the moment of inertia of the Steel pipe.

Substitute  for:

Step No: 3

Calculate the moment about y-direction.

Here,  is the force in the x-direction and  is the perpendicular distance.
Substitute 10000 N for  and 200 mm for .

Calculate the moment about z-direction.

Here,  is the force in the x-direction and  is the perpendicular distance.
Substitute 10000 N for  and 150 mm for .

Here, the negative sign in the moment about z-direction is due to the moment acts in the clockwise direction.
The force  creates the moment about z axis and the force  creates the torsion in y direction. Therefore, the moments  and  cause for the bending and twisting moments respectively and the respective stresses are bending stress and torsional shear stress.

Step No: 4

Calculate the bending stress at K as follows:

Here, distance of the point K from the axis is c.
Substitute  for ,  for  and 0.051 m for y.

Here, the negative sign indicates that the stress at the point K is compressive in nature.
 

Step No: 5

Calculate the shear stress at K as follows:
 

Substitute  for ,  for  and 0.051 m for r.

Step No: 6

Calculate the average stress as follows:

Substitute  for  and 0 for 

Calculate the maximum shear stress as follows.

Substitute  for ,  for  and 0 for 

Therefore, the maximum shear stress is .

Step No: 7

Calculate the maximum normal stress at K as follows.

Substitute  for  and  for .

Therefore, the maximum normal stress at K is .

Step No: 8

Calculate the minimum normal stress at K as follows.

Substitute  for  and  for .

Therefore, the minimum normal stress at K is .

Answers