- #1
tuoni
- 61
- 0
Does anyone have a quick way of estimating the amount of internal pressure a sealed tube would be able to handle without failing?
In summary: For a fixed tube, it can handle up to 400,000 psi. For the telescoped variant, it can handle up to 1.5 million psi.
- #2
FredGarvin
Science Advisor
- 5,093
- 10
First: How do you define "failing?"
Second: It is easy, but the freshman year easy method does not account for stresses near the ends of the tube, only "far away" from them.
Are you attempting to use very high pressures? I hope not.
Second: It is easy, but the freshman year easy method does not account for stresses near the ends of the tube, only "far away" from them.
Are you attempting to use very high pressures? I hope not.
- #3
tuoni
- 61
- 0
This is only a theoretical experiment. Too dangerous.
The reason I ask is because I became quite interested when I read about the Russian 7.62x42 mm cartridge a while back. It is a true silent cartridge, the only sound is from the action of the firearm. It utilises a special steel "capsule" that traps the escaping gases and unburned propellant within the casing.
The attached file "pressure.png" depicts a crude simplification of the setup.
The inner tube is able to move forward, providing additional space for the ejecta and propelling the bullet. I just thought this was a very interesting concept, and thought of doing some simple calculations just too see the outcome. At first for a fixed tube, how it would be able to handle various pressures, and then the telescoped variant.
Failing would mean not being able to safely trap the ejecta, slight deformation would be acceptable. The breech and chamber provide support for the rear and sides of the tube, so the critical part would be the front. In the first example, the front o the tube would have to stay intact. In the second example, the projecting tube would have to remain intact, and be held in place by the outer tube. The illustration doesn't include any such system, and I don't really know the exact method used, but let's assume that the tube only moves forward 3/4, the rest of the rear is somehow used to prevent the inner tube from being propelled along with the bullet.
The reason I ask is because I became quite interested when I read about the Russian 7.62x42 mm cartridge a while back. It is a true silent cartridge, the only sound is from the action of the firearm. It utilises a special steel "capsule" that traps the escaping gases and unburned propellant within the casing.
The attached file "pressure.png" depicts a crude simplification of the setup.
The inner tube is able to move forward, providing additional space for the ejecta and propelling the bullet. I just thought this was a very interesting concept, and thought of doing some simple calculations just too see the outcome. At first for a fixed tube, how it would be able to handle various pressures, and then the telescoped variant.
Failing would mean not being able to safely trap the ejecta, slight deformation would be acceptable. The breech and chamber provide support for the rear and sides of the tube, so the critical part would be the front. In the first example, the front o the tube would have to stay intact. In the second example, the projecting tube would have to remain intact, and be held in place by the outer tube. The illustration doesn't include any such system, and I don't really know the exact method used, but let's assume that the tube only moves forward 3/4, the rest of the rear is somehow used to prevent the inner tube from being propelled along with the bullet.
Attachments
FAQ: Estimating Internal Pressure in Sealed Tubes
How is internal pressure estimated in sealed tubes?
Internal pressure in sealed tubes is typically estimated using a pressure gauge or a pressure transducer. The gauge or transducer measures the pressure inside the tube and provides a reading. This reading can then be used to estimate the internal pressure.
What factors can affect the accuracy of internal pressure estimates?
Several factors can affect the accuracy of internal pressure estimates. These include the type and quality of the pressure gauge or transducer, the material and thickness of the tube, and the temperature and composition of the gas or liquid inside the tube.
Can internal pressure be estimated in tubes with non-uniform shapes?
Yes, internal pressure can be estimated in tubes with non-uniform shapes. However, the estimation process may be more complex and require additional calculations to account for the varying shapes and dimensions of the tube.
How can internal pressure be calculated if the tube is not completely sealed?
If the tube is not completely sealed, the internal pressure can still be estimated by using a pressure gauge or transducer. However, the reading may not be as accurate, and additional factors such as leaks or air pockets may need to be taken into account.
Are there any safety precautions to consider when estimating internal pressure in sealed tubes?
Yes, it is important to follow proper safety precautions when estimating internal pressure in sealed tubes. This may include wearing protective gear such as gloves and safety glasses, and ensuring that the pressure gauge or transducer is functioning properly before use.