COE 3001 Lecture 11: 11+Pressure+Vessels
23 Nov 2016
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Pressure vessels are examples of structures under plane stress. They are enclosed structures containing fluids under pressure. Biological examples include blood vessels, the bladder, heart chambers, and certain types of cells, such as white blood cells. We will focus specifically on thin- walled pressure vessels. Thin-walled does not have a precise definition, though typically the ratio of the radius of the vessel r to the thickness of the vessel wall t is about 5-10 or more. Let us first consider a spherical vessel within a net internal pressure p: The total force p applied to a single hemisphere of the vessel is given by: If we now cut the vessel into two hemispheres, we reveal the stress acting in the wall of the vessel. This is the stress we are interested in. Essentially what is happening is that the stress generated in the vessel wall is balancing out the internal pressure of the pressure vessel.
