Homework 3:

 

1- a) A 15 mm dia. Steel bar is subjected to a tensile load of 10,500 N; calculate
a) The bar tensile stress. (σ = 59.42 MPa)

b) Choose a suitable steel if the required SF is 5. (Material = EN1A)

 

2- A structure suspended by EN3 tie-bars is equivalent to a load of 120,000 N. The tie-bars each have a diameter of 30 mm. If the SF is 10, calculate the minimum number of tie-bars. (N = 4 tie-bars)

 

3- In a cylinder of bore 70 mm the pressure is 5 N/mm². The cover plate is secured by M10 studs with a required SF of 10. Determine the minimum number of studs using:  a) EN1A, b) En3.

 

4- What diameter of EN8 shaft will withstand a tensile load of 60,000 N if the required SF 8? (d = 31.4)

 

5- A 70 mm dia. shaft is subjected to a tangential load of 80 kN. With a SF of 5, design a suitable feather key for the shaft.

 

6- The maximum explosion pressure in the cylinder of a combustion engine is 1.0 N/mm². The piston has a diameter of 100 mm. Determine the minimum diameter of gudgeon pin, using a suitable steel, with a required SF of 15.
(EN1A- D =17.32 mm, EN3- D =16.66 mm, EN8- D =14.23 mm, EN32A- D =15.81mm, EN42- D =14.43 mm)

 

7- This EN1A bar of Fig.1 is subjected to a load of 12,000 N with a required SF of 10. Determine suitable sizes for dimensions d, D, and h. (d = 19.07 mm, D = 8.01 mm, and h = 26.97 mm)

 

8- A flanged coupling connects two transmission devices with pins of diameter 12 mm made of EN3 steel, at a pitch circle diameter of 160 mm. If a torque of 3,000 N m is applied with a required safety factor of 6, calculate the minimum number of pins required. (8 pins)