Timothy A. Philpot - Mechanics of materials _ an integrated learning system-John Wiley (2017)

CHAPTER14
Pressure Vessels
14.1 Introduction
Pressure vessels are used to hold fluids such as liquids or gases that must be stored at
relatively high pressures. Pressure vessels may be found in settings such as chemical
plants, airplanes, power plants, submersible vehicles, and manufacturing processes.
Boilers, gas storage tanks, pulp digesters, aircraft fuselages, water distribution towers,
inflatable boats, distillation towers, expansion tanks, and pipelines are examples of pressure
vessels.
A pressure vessel can be described as thin walled when the ratio of the inside radius
to the wall thickness is sufficiently large that the distribution of normal stress in the
radial direction is essentially uniform across the vessel wall. Normal stress actually
varies from a maximum value at the inside surface to a minimum value at the outside
surface of the vessel wall. However, if the ratio of the inside radius to the wall thickness
is greater than 10:1, it can be shown that the maximum normal stress is no more than
5 percent greater than the average normal stress. Therefore, a vessel can be classified as
thin walled if the ratio of the inside radius to the wall thickness is greater than about
10:1 (i.e., r t > 10).
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