B. A punching press is required to punch 30 mm diameter holes in a plate of 20 mm thickness at the rate of 20 holes/mm. It requires 6Nm of energy / mm2 of sheared area. If the punching takes place in 1/10 of sec and rpm of the flywheel varies from 160 to 140, determine the weight of the flywheel having radius of gyration is 1m.

Mumbai University > Mechanical Engineering > Sem 5 > Theory of Machines-II

Marks: 10 Marks

Year: May 2016

Give data:-

d=30 mm.

t=20mm

rate of holes= 20 holes/min

Energy Required= 6N-m

Radius of gyration k=1m

T=0.15

$n_1 =160 rpm \\ n_2 = 140 rpm$

To find weight,

Calculating the max fluctuation of energy ΔEmax

Energy req. Per hole is given by

$E= E_1$ *sheared area per hole

E$=6*Π*dt …