Pressure vessels are all too common in our lives: oil tankers, storage tanks, nitrogen tanks for coolants, you name it. Since its so commonly used, we need to understand the stresses acting in it to equip ourselves in designing safe pressure vessels
Pressure vessels are all too common in our lives: oil tankers, storage tanks, nitrogen tanks for coolants, you name it. Since its so commonly used, we need to understand the stresses acting in it to equip ourselves in designing safe pressure vessels
The thin-walled pressure vessel analysis is formulated based on the assumption that the vessels fulfil the criteria r/t ≤ 10, i.e. the vessel is sufficiently thin with respect to its radius.
Here we look at the 2 most common types of vessels:
Let’s look at a cylindrical vessel. If we consider a tiny element on the vessel’s shell, we can split the stress into the components acting in the longitudinal (axial) direction and the hoop or circumferential direction.
To give you a better understanding on how these stresses act, we dissect the vessel:
Now that we know the stress components, let’s look at the formula to calculate these:
For a spherical vessel, the curvature is constant throughout the entire sphere and therefore σ_{long} and σ_{hoop} are the same.
The 3rd stress component in pressure vessels is the radial stress. It is basically the normal stress acting in the radial direction due to the pressure. It’s the same as you using your palm to press against the wall: you feel the compressive effect from the normal stress.
The exact theory for the radial stress distribution is complex, but we estimate it as:
Let’s look at an example now.
The thin-walled pressure vessel analysis is formulated based on the assumption that the vessels fulfil the criteria r/t ≤ 10, i.e. the vessel is sufficiently thin with respect to its radius.
Here we look at the 2 most common types of vessels:
Let’s look at a cylindrical vessel. If we consider a tiny element on the vessel’s shell, we can split the stress into the components acting in the longitudinal (axial) direction and the hoop or circumferential direction.
To give you a better understanding on how these stresses act, we dissect the vessel:
Now that we know the stress components, let’s look at the formula to calculate these:
For a spherical vessel, the curvature is constant throughout the entire sphere and therefore σ_{long} and σ_{hoop} are the same.
The 3rd stress component in pressure vessels is the radial stress. It is basically the normal stress acting in the radial direction due to the pressure. It’s the same as you using your palm to press against the wall: you feel the compressive effect from the normal stress.
The exact theory for the radial stress distribution is complex, but we estimate it as:
Let’s look at an example now.