The physics behind rifle barrel harmonics

[tlwhite0311]

Hi all this is my first post. I am trying to do a simulation project revolving around the transient response of a rifle barrel after incurring a large pressure spike in the chamber. However, I have not found any firearms textbooks explicitly addressing this, and when I open a vibrations textbook I feel lost after 10 min of looking around. I was hoping if someone could point me in the right direction to the part of mechanical vibrations I should be looking. Thanks.

 

[Tom.G]

https://www.google.com/search?source=hp&q=natural+frequency+of+steel+bar

The first hit is: http://www.cmrp.com/blog/uncategori...ural-vibration-frequency-of-a-steel-tube.html

 

[JRMichler]

Attempting to simulate something that you do not understand is a recipe for failure. You need to understand the relationship between rate of pressure rise, duration of pressure, and natural frequency. You also need to understand the various vibration modes applicable to gun barrels. And the mechanisms for exciting those modes. And how chamber pressure vs time curve excites modes of what frequency. And the effect of the bullet traveling through the barrel. You really need to get through a course in basic vibrations before tackling this project.

Try a google search with search terms gun barrel vibrations. That will turn up a lot of good information.

 

[tlwhite0311]

Attempting to simulate something that you do not understand is a recipe for failure. You need to understand the relationship between rate of pressure rise, duration of pressure, and natural frequency. You also need to understand the various vibration modes applicable to gun barrels. And the mechanisms for exciting those modes. And how chamber pressure vs time curve excites modes of what frequency. And the effect of the bullet traveling through the barrel. You really need to get through a course in basic vibrations before tackling this project.

Try a google search with search terms gun barrel vibrations. That will turn up a lot of good information.

Exactly why I'm looking for resources. If there is one thing I've learned in school it's that courses don't really teach you anything. YOU teach yourself everything.

 

[Nidum]

This is a very complex transient response problem . Vibration effects may well be involved in the response but thinking just about vibration is not a good way to start trying to analyse this problem .

Search using the keywords: gun/rifle + barrel + stress/strength . You will find a large amount of useful information . Search on images as well .

 

[Dr.D]

Are you interested in radial vibrations, longitudinal vibrations, bending vibrations, or just what sort of motion?

 

[Dr.D]

Exactly why I'm looking for resources. If there is one thing I've learned in school it's that courses don't really teach you anything. YOU teach yourself everything.

To a limited extent this is true, but, and this is the big part, a good course will present the material clearly, in a well organized manner that facilitates learning. This is quite different from trying to teach yourself in which you pick up bits and pieces in a random fashion as you encounter them. A good course is always an advantage.

 

[tlwhite0311]

To a limited extent this is true, but, and this is the big part, a good course will present the material clearly, in a well organized manner that facilitates learning. This is quite different from trying to teach yourself in which you pick up bits and pieces in a random fashion as you encounter them. A good course is always an advantage.

Again I disagree my entire time in academia the lectures have been anything but clearly presented information in an organized manner. I have literally taught myself everything by reading the books and working sample problems and looking up videos on the internet. This is the general consensus of the student body that I have experienced. Also, when I have worked in industry in internships etc, anytime I needed to learn something there I was with a textbook and paper open teaching myself the knowledge. If I ever need an actual lecture there are plenty of free online lectures but short to the point youtube videos seem to do a much better job. Reddit has also been a huge help.

 

[Dr.D]

Again I disagree my entire time in academia the lectures have been anything but clearly presented information in an organized manner.

If you will note, I said, " A GOOD course is always an advantage." Not all courses are good, and in today's academic environment, there is progressively little emphasis on teaching. Good luck with your approach.

 

[Baluncore]

I am trying to do a simulation project revolving around the transient response of a rifle barrel after incurring a large pressure spike in the chamber.

There will be pressure waves that propagate along the barrel. They will partially reflect from changing diameters and reflect from both ends of the barrel.

If the barrel is not supported symmetrically about the boreline axis, then axial energy will be transformed into transverse waves that will cause oscillations of the boreline aim.