Q.5 a high-pressure cylinder consists of a steel tube with inner and outer diameters of 30 and 50 mm respectively. It is jacketed by an outer steel tube, having an outer diameter of 70 mm.
Answers
Answer:
A cylinder is said to be 'THIN' if the ratio of its inner diameter to the thickness of wall is more than 20. And when it below 20 then it is termed as thick cylinder.
A thin cylinder is subjected to two principal stresses, Circumferential stresses (along circumference) and longitudinal stress (along length).
For thin cylinders circumferential stress is twice the longitudinal stress.
In thick cylinders, it is assumed that the tangential stress is uniformly distributed over cylinder wall thickness, whereas the tangential stress has highest value at inner surface and gradually decreases towards the outer surface.
The radial stress is negligible in thin cylinders but has considerable magnitude in thick cylinders.
Lame's equation is based on maximum principal stress theory of failure, and is used when the material of cylinder is brittle.
Clavarino's and Birnies equations are based upon maximum strain theory of failure, and is used when the material is ductile.
A compound cylinder is made up of two cylinders which are fitted on each other by shrinkage technique, the outer is called Jacket and inner is called simply cylinder.
Autofrettage is a process of prestressing the cylinder before it is actually put into service. It is done to increase the pressure capacity of cylinders.
Explanation: