Summary STRESS ON THIN-WALLED PRESSURE VESSELS

CE 332(HYDRAULICS)
BSCE-3A/3B

STRESS ON THIN-WALLED PRESSURE VESSELS

I. LEARNING OUTCOME:

• Identify thin wall or thick wall pressure vessels
• Discuss the difference between longitudinal and circumferential stress
• Perform thin wall pressure vessel design calculations

II. DISCUSSION

Thin-walled Pressure Vessels

The distinction between thin vs. thick wall pressure vessels is determined by the ratio between the mean
radius of the vessel and the thickness of the wall. If this ratio is greater than 10, the vessel is considered a
thin wall pressure vessel. If the ratio is less than 10, the vessel is considered a thick wall pressure vessel.




A tank or pipe carrying a fluid or gas under a pressure is subjected to tensile forces, which resist bursting,
developed across longitudinal and transverse sections.


A. TANGENTIAL STRESS, σt
Also called Circumferential Stress.

Consider the tank shown being subjected to an internal pressure p. The length of the tank is L and the wall
thickness is t. Isolating the right half of the tank:




The forces acting are the total pressures caused by the internal pressure p and the total tension in the walls
T.
F=pA=pDL
T=σtAwall =σttL