A solid circular shaft of 3m length and 200mm diameter is subjected to a torque of 100knm. Find relative rotation between end x section of the shaft. Take g = 1×10^5 nmm^2
We have given the followings in the question, Diameter of shaft, d= 200 mm
Length of shaft L = 3 m = 3000 mm
Torque , T = 100 KNm = 100*10^6 Nmm Modulus of Rigidity, G = 1*105 N/mm2 = 105 MPa ( since 1 MPa = 1 N/mm2)
We know that rotation of shaft relative to cross section is given by angle of twist, θ = TL / GJ
Where J= Polar moment of Inertia
for solid shaft, J= πd4 / 32 = π*(200)4 / 32 = 1.57 *108 mm4
So θ = (100*106*3000) / 105 * 1.57*108
= 0.0191 rad = 0.0191*180/π
θ = 1.09 degree
Hence relative rotation between end x section is 1.09 degree.