Solved Problems: Strength of Materials - Torsion

1.A metal bar of 10mm dia when subjected to a pull of 23.55KN gave and elongation of 0.3mm on a gauge length of 200mm. In a torsion test maximum shear stress of 40.71N/mm² was measured on a bar of 50mm dia. The angle of twist measured over a length of 300mm being 0°21’. Deter poisson’s.

Solution:                                                                       

Given data:                                                                   

diad            =                 10mm                  

pull P                   =                 23.55KN             

elongation SL =    0.3mm                                    

Gauge length        =       200mm                

Torsion Test                                                                           

(or)             =                 40.71 N/mm²                

Dia              =                 500mm                

Twist angle           =                 0^o21’          

length                   =                 300 mm               

Asked                                                        

Problem-2:

A hollow shaft dia ratio 3/5 is required to transmit 450Kw at 1200pm, the shearing stress in the shaft must not exceed 60N/mm² and the twist in a length of 2.5m is not to exceed 1^o. Calculate the minimum external of the shaft. Take, C=8.0KN/mm².

Problem-3:

What must be the length of a 5mm dia aluminium wine so that it can be twisted through 1 complete revolution without exceeding a shear of 42N/mm². Take, G=27 GPO.

Problem-4:

A solid steel shaft has to transmit 75Kw power at 200 pm. Taking allowable shear stress 70Mpo. Find suitable dia of shaft with the maximum torque transmitted on each revolutions exceeds by mean by 30% 1.3 times mean.