I am building a pressure vessel mad
I am building a pressure vessel mad
(OP)
I am building a pressure vessel made of a round tube with two disk closures; the closures are retained by 1/4" bolts. I would like to minimize the distance necessary to install the retention bolts from the end of the tube. Would you calculate this distance with simple average double shear, or some compression/ single shear calculations because of the rounded surface of the bolts?
RE: I am building a pressure vessel mad
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: I am building a pressure vessel mad
are the 1/4" bolts working in tension or shear ?? ie is the bolt axis aligned to the radial direction, around the tube, or normal to the "closure disc" ?
"because of the rounded surface of the bolts" ... huh ??
another day in paradise, or is paradise one day closer ?
RE: I am building a pressure vessel mad
Not sure if that upload will go through properly ^
The bolts are working entirely in shear arranged radially about the tube. Would like a nice way to calculate the amount of tube material needed to keep the bolts retained. They should be placed as close as possible to the end of the tube meaning that the axial stresses on the tube material upwards of the pressure and bolts becomes critical.
I'll get a better description up in a minute with some CAD captures; sorry for the poor initial explanation.
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
Jack
RE: I am building a pressure vessel mad
Jack
RE: I am building a pressure vessel mad
It is fairly easy to set up a hydrostatic test in a water tank and crank the internal pressure up to see the point it fails. I suppose if it doesn't then shave off some metal and give it another try until it does or crank up the pressure to see how much margin there is. Keeping it submerged prevents pinhole leaks from getting to people and injuring them. Much better than calculations that are depend on simplifications.
Tearout calculations usually assume that no threads are in shear or bearing. Without match-reaming close-fit fasteners it is likely that only two of the four fasteners will carry most of the load.
I see I'm not the only one considering hydrostatic testing ". In the professional aerospace world, room temperature hydrostatic test results are extrapolated to operational conditions by detailed thermo-mechanical modeling and then instrumented testing is conducted to verify the design. This is well beyond the capabilities of the hobbyist." https://www.rocketryforum.com/threads/experimental...
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
Regards & keep your head down :)
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
Appreciate it,
Jack
RE: I am building a pressure vessel mad
I.e. make the threaded part in the outer cylinder and then machine down the lower section into a tight pin. see below.
Also this is similar to a commercial flange connection device called a "Lok-O ring" flange kit made by TDW. This is good for pressures up to 100 bar at 6 inch. The new version actually uses the second option I put in below with moveable "leaves". The older version is the second link below. I'm a great believer that you should use things developed, tested and certified by others...
http://www.tdwilliamson.com/content/Bulletins/1100...]
http://www.ubsco.net/products/uploads/2014/05/LOCK...
That way you won't have the same issue as having a slightly small pin inside a hole tearing out and can ensure that the failure is in shear in the pin.
You might need a few more pins, but I think this is a much better and more easily designed system.
Not sure why you want to reduce the end distance? Anything less than 1D of the hole will cause issues I think if you do it as per the original design.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: I am building a pressure vessel mad
RE: I am building a pressure vessel mad
as a rocket, you can probably improve the end-cap thickness (to save weight). It need to be thick at the edge (for the heli-coil) but probably doesn't need to be so thick in the middle. I assume you're CSK-ing the screws ... thickness of the cylinder wall is possibly a design issue (is it a fatigue concern ?)
RE: I am building a pressure vessel mad
Looks too much like the challenger solid rocket boosters to me....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: I am building a pressure vessel mad
I wonder when the peak load happens on this end-cap ... when the solid fuel is just about spent ?
another day in paradise, or is paradise one day closer ?