Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 63 users online :: 5 registered, 0 hidden and 58 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Formula for burst pressure of a flat plate or sheet.

Post questions and info about hybrid (compressed gas with fuel) powered cannons here. This includes discussion about fuels, ratios, ignition systems, build types, safety, and anything else relevant.
Sponsored 
  • Author
    Message

Formula for burst pressure of a flat plate or sheet.

Unread postAuthor: Jeeperforlife » Mon May 10, 2010 9:01 am

I am looking for the formula for burst pressure of steel and aluminum flat plate. I am trying to figure some different burst disks and end plates for my new gun I am building.

Marcus
  • 0

Life is tough, it's even tougher when you're stupid. -John Wayne

Marcus
User avatar
Jeeperforlife
Staff Sergeant
Staff Sergeant
 
Posts: 108
Joined: Tue Jan 15, 2008 4:51 pm
Country: United States (us)
Reputation: 0

Unread postAuthor: Moonbogg » Mon May 10, 2010 6:52 pm

I made a hybrid with a flat plate at one end of the chamber. I am not a math wizz nor am I an engineer, so I used a software program to calculate the yield for me. If noone gives you equations, I will run the numbers through my program for you if you want. My hybrid has not exploded yet btw :D
  • 0

User avatar
Moonbogg
Major General
Major General
 
Posts: 1375
Joined: Mon Oct 13, 2008 10:20 pm
Location: whittier, CA USA
Reputation: 0

Re: Formula for burst pressure of a flat plate or sheet.

Unread postAuthor: SpudFarm » Tue May 11, 2010 5:07 am

Jeeperforlife wrote:I am looking for the formula for burst pressure of steel and aluminum flat plate. I am trying to figure some different burst disks and end plates for my new gun I am building.

Marcus


You might get a good answer if you ask "D_Hall"
Try giving him a PM if he dosen't reply here.
  • 0

"Made in France"
- A spud gun insurance.
User avatar
SpudFarm
Donating Member
Donating Member
 
Posts: 2563
Joined: Sat Nov 04, 2006 9:39 am
Location: Norway Trondheim area
Reputation: 0

Unread postAuthor: velocity3x » Tue May 11, 2010 10:32 am

Moonbogg wrote:I used a software program to calculate the yield for me.


@Moonbogg
Did you find COSMOS predictions to be accurate?
  • 0

User avatar
velocity3x
Brigadier General
Brigadier General
 
Posts: 827
Joined: Fri Jun 05, 2009 3:09 pm
Location: Yuma, Arizona
Country: United States (us)
Reputation: 7

Unread postAuthor: Moonbogg » Tue May 11, 2010 6:54 pm

velocity3x wrote:
Moonbogg wrote:I used a software program to calculate the yield for me.


@Moonbogg
Did you find COSMOS predictions to be accurate?


If the cannon not failing means anything, then yes, they were accurate. There were some variables in my design that cosmos didn't take into account, such as weld filler material and post weld heat treatment. But the welds are large beads and the filler material is comparable in strength to the base material, so with heat treatment I am assuming that the FOS is at least in the ball park that cosmos predicted, around 4.2 @ 200psi before yield.
I always thought aluminum was a ductile material, but I have noticed that the tensile is not much higher than the yield, so if the cannon approaches the yield at all, then it is also approaching ultimate failure which would not be far behind. What about you? Do you trust cosmos?
  • 0

User avatar
Moonbogg
Major General
Major General
 
Posts: 1375
Joined: Mon Oct 13, 2008 10:20 pm
Location: whittier, CA USA
Reputation: 0

Unread postAuthor: velocity3x » Tue May 11, 2010 8:46 pm

Moonbogg wrote: What about you? Do you trust cosmos?


I absolutely trust it to determine FOS. I feel very comfortable with its calculations. I've never used it to predict a point of total failure....like a burst disk. Do you think it would would be accurate enough to do it?
  • 0

User avatar
velocity3x
Brigadier General
Brigadier General
 
Posts: 827
Joined: Fri Jun 05, 2009 3:09 pm
Location: Yuma, Arizona
Country: United States (us)
Reputation: 7

Unread postAuthor: Moonbogg » Tue May 11, 2010 9:05 pm

velocity3x wrote:
Moonbogg wrote: What about you? Do you trust cosmos?


I absolutely rely on it to determine FOS. My metal of choice is aluminum with normal operating pressure of 1Kpsi. I feel very comfortable with its calculations. Actual, I was wondering if you had every used COSMOS to predict the bursting point of a burst disk design? I only have pneumatics but, it seems to me that COSMOS could be extremely handy for designing burst disks for various pressure ratings. Do you think it would would be accurate enough to do it?


I think it would be accurate enough to at least get you in the ballpark range you want to be. It calculates yield by default thought, right? Yield is different from tensile failure, so thats something that would have to be thought about. You can create your own materials with custom mechanical properties. Perhaps one could use the tensile strength in place of the yield strength, so when the FOS reaches zero, it should actually break. I duno, its worth playing around with. Maybe i'll test it on something easy to duplicate results with, like aluminum foil. Once I get the right numbers down, I would have an idea of how to treat other materials in respect to their tensile/yield strengths.
  • 0

User avatar
Moonbogg
Major General
Major General
 
Posts: 1375
Joined: Mon Oct 13, 2008 10:20 pm
Location: whittier, CA USA
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: Jeeperforlife » Tue May 11, 2010 10:02 pm

Moonbogg wrote:I made a hybrid with a flat plate at one end of the chamber. I am not a math wizz nor am I an engineer, so I used a software program to calculate the yield for me. If noone gives you equations, I will run the numbers through my program for you if you want. My hybrid has not exploded yet btw :D


Thanks,
But I want to test a long list of ideas, I really don't think you want to go through it. If all else fails I will let you know some ideas and maybe you could do a couple for me. I will see.

SpudFarm wrote:You might get a good answer if you ask "D_Hall"
Try giving him a PM if he doesn’t reply here.


I did think of that, however I know he is busy and would prefer not to bother him if it is not needed. However I probably will if I don't get any other leads.

Thanks
  • 0

Life is tough, it's even tougher when you're stupid. -John Wayne

Marcus
User avatar
Jeeperforlife
Staff Sergeant
Staff Sergeant
 
Posts: 108
Joined: Tue Jan 15, 2008 4:51 pm
Country: United States (us)
Reputation: 0

Return to Hybrid Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'