written 5.1 years ago by
sesha321
• 290

•
modified 5.1 years ago

given data :
power transmitted P = 550KW
Number of rotations N = 115rpm
i) Here what to be found out is the diameter of the solid shaft. This can be found by using torsion equation
$${T\over J}= {\tau\over R}$$
torque can be calculated by the formulae
$$P= {2\pi\ NT\over60}$$
P is given as 550KW so T = 45.67 KNm
J is the polar moment of inertia
it is calculated by the formulae
$$J={\pi\ r^4\over2}$$
by substituting the value of J in the torsion equation we get
 $${T\over\tau} = {\pi\ r^3\over 2}$$
the radius can be calculated by the above equation
and shear stress is given as 78MPa by substituting all the above equations
we get the radius of the shaft
r =0.07196 meters or 71.96 mm
ii) for the hollow shaft
R1 = internal diameter
R2= external diameter
R1 = 0.75* R2
$${T\over\tau} = {\pi\ (R2^4R1^4)\over (2(R2))}$$
we get R2 = 0.114meters and R1=0.085