In a cooling system, a 24mm diameter shaft is used to connect a fan at D...

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In a cooling system, a 24mm diameter shaft is used to connect a fan at D to a pulley at C and supported by a thrust bearing at A and ball bearing at B. The pulley C (diameter 800mm) weighing 35kg provides the torque needed to rotate the propellers D at constant speed of 1000rpm with the pulley belt tension T1 = 300N & T2 = 200N. The rotation of the fan which has 3 blades creates a compressive force of 9kN on the shaft. The mass of the fan is 36kg. Gravity pull is 9.81m/s2. B C 200mm a) By ignoring stress concentration factor, I. Calculate the maximum axial stress in the shaft. II. Calculate the maximum torsion stress in the shaft. III. Calculate the maximum bending stress in the shaft. 100 125mm H HAT b) Stress concentration occur due to a transverse hole 4mm diameter at C and D which is use to lock the pulley and fan. If the shaft is machined from an AISI 1045 HR rod, I. Find the stress concentration factor for bending and twisting. II. Calculate the highest stress acting on the shaft. III. Find the endurance limit and determine whether the shaft has infinite life (use modified Goodman criterion). Safety factor is 1.20. If not, determine the life in minutes. In a cooling system, a 24mm diameter shaft is used to connect a fan at D to a pulley at C and supported by a thrust bearing at A and ball bearing at B. The pulley C (diameter 800mm) weighing 35kg provides the torque needed to rotate the propellers D at constant speed of 1000rpm with the pulley belt tension T1 = 300N & T2 = 200N. The rotation of the fan which has 3 blades creates a compressive force of 9kN on the shaft. The mass of the fan is 36kg. Gravity pull is 9.81m/s2. B C 200mm a) By ignoring stress concentration factor, I. Calculate the maximum axial stress in the shaft. II. Calculate the maximum torsion stress in the shaft. III. Calculate the maximum bending stress in the shaft. 100 125mm H HAT b) Stress concentration occur due to a transverse hole 4mm diameter at C and D which is use to lock the pulley and fan. If the shaft is machined from an AISI 1045 HR rod, I. Find the stress concentration factor for bending and twisting. II. Calculate the highest stress acting on the shaft. III. Find the endurance limit and determine whether the shaft has infinite life (use modified Goodman criterion). Safety factor is 1.20. If not, determine the life in minutes.

Answer rating: 100% (QA)

SOLUTION a I Maximum axial stress in the shaft Compressive force from fan 9 kN Area of shaft r2 12mm2 452 mm2 Maximum axial stress Compressive force A... View the full answer