Question

difference between thin cylinder and thick cylinder

Answer 1

Thick cylinder is cylinder whose wall thickness is greater than 1/20 times of its internal diameter. (If d =20mm then its thickness would be greater than 400mm) or cylinder whose wall thickness is 7% more than its internal diameter.
Thin cylinder is cylinder whose wall thickness is lesser than 1/20 times of its internal diameter. (If d =400mm then its thickness would be less than 20mm) or cylinder whose wall thickness is 7% less than its internal diameter.

Answer 2

Thick Vs Thin Cylinder:

• In thin cylindrical shells, the stresses are uniformly distributed all the way through the wall. The type of stresses established in thin cylinders is hoop and longitudinal stress.  

• For the thin walled equations below the wall thickness is smaller than 1/20 of tube or cylinder diameter.

• In thick wall cylinder, the stresses are not uniformly distributed throughout the wall.

• A cylinder in which the wall thickness is larger than 1 / 20 of internal diameter it is known as the thick cylinder.

Hope it helped......