Torsion Sample Questions

THE UNIVERSITY OF ZAMBIA
SCHOOL OF ENGINEERING
DEPARTMENT OF MECHANICAL ENGINEERING
ME 332 STRENGTH OF MATERIALS I

SAMPLE PROBLEMS-TORSION OF CIRCULAR SHAFTS AND THIN WALLED SECTIONS

QUESTION 1

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QUESTION 2

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QUESTION 4

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Q6. The drive shaft for a truck (outer diameter 60 mm and inner diameter 40 mm) is running at 2500 rpm (see figure Q6).
(a) If the shaft transmits 150 kW, what is the maximum shear stress in the shaft?
(b) If the allowable shear stress is 30 MPa, what is the maximum power that can be transmitted?

Figure Q6.
SOLUTION:
Drive shaft for a truck

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Q7. A tubular shaft being designed for use on a construction site must transmit 120 kW at 1.75 Hz. The inside diameter of the shaft is to be one-half of the outside diameter. If the allowable shear stress in the shaft is 45 MPa, what is the minimum required outside diameter d

SOLUTION
Tubular shaft

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Q8. The shaft ABC shown in the figure is driven by a motor that delivers 300 kW at a rotational speed of 32 Hz. The gears at B and C take out 120 and 180 kW, respectively. The lengths of the two parts of the shaft are L1 =1.5 m and L2 = 0.9 m. Determine the required diameter d of the shaft if the allowable shear stress is 50 MPa, the allowable angle of twist between points A and C is 4.0°, and G =75 GPa.

SOLUTION:

Motor-driven shaft

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Q9. Calculate the shear stress τ and the angle of twist ɸ (in degrees) for a steel tube (G =76 GPa) having the cross section shown in figure Q9. The tube has length L = 1.5 m and is subjected to a torque T =10 KN m.

Figure Q9

SOLUTION Steel tube

Q10. A thin tubular shaft of circular cross section(see