Compound Cylinders can anyone explain the advantages of shrinking one cylinder over another,?

Question

or other techniques that may be used to adress a problem of rising internal pressure in a thick cylinder? iv tried to google it but cant get much

Answer 1

The reason for shrinking one cylinder over another is to impose a compressive stress on the internal cylinder.
The internal cylinder is being prestressed in compression.
Then, when the internal cylinder is pressurized, it can be pressurized to a much higher level before reaching it's maximum design tensile stress, because it starts at a high value of negative compressive stress. The outer vessel is usually made from a material with a very high allowable tensile stress.


Another way to accomplish the same thing is to wind a forged cylinder with many layers of very high tensile strength alloy wires, about 1/8" square, in order to prestress the internal cylinder in compression. Pressure vessels with operating pressures up to 60, 000 psi are made in this way.
There is a Swedish Co. that has developed a system for building these vessels. The high pressures and temperatures that can then be developed allow for imbedding special coatings onto ceramic materials and for creating ultra fine surface finishes in casting and forging parts that require very accurate balancing.

These vessels are usually referred to as Isostatic Presses.