Maximum Bending Stress in a Pipe?
Maximum Bending Stress in a Pipe?
(OP)
i was just told at work that i need to find out if some pipes can withstand a force or not, but dont have much to go off of yet. they just want some formulas. im wondering what info i'll need. one end of each pipe goes into an engine, and the other ends either go straight out to a hanger where theyre held in place, or else turn 90 degree and go to a hanger where theyre fixed. the lengths and diameters of the pipes are all different. the pipes are welded and brazed, so no threads to turn to give more movement. they want to jack the engine up an inch temporarity, and want to know if the pipes will be able to flex that inch or if they'll break.
not much to go off of i know, which is why im so lost here. can anyone tell me what info i will need, or have any idea how to start tackling this problem?
not much to go off of i know, which is why im so lost here. can anyone tell me what info i will need, or have any idea how to start tackling this problem?





RE: Maximum Bending Stress in a Pipe?
Pulling/pushing: sigma = P/A (http://
Bending: sigma = My/I (http:/
Twisting: tau = Tc/J (http://
Pressure in a thick walled cylinder: http://ww
Buckling: http://en.wikipedia.org/wiki/Buckling
What's the application here? Often plant/process sort of stuff needs to be signed off by a professional engineer. Do you have a PE looking at your work? Sounds like someone might get hurt if there's a failure - it'd be good if someone with some experience in structural mechanics checked over your calculations. What sort of background do you have?
RE: Maximum Bending Stress in a Pipe?
You (you and your supervisor) need to think about what will bend first (engine casting, engine flange, valve, support, fitting, pipe, etc) BEFORE trying this lift.
The pipe is relatively "soft" compared to a casting or an "engine" and so the flex of the pipe will help cause yielding and failure elsewhere that you don't intend. Disconnect the piece, support the pipes and fittings that will "droop" or sag from their weight with jigs, chainfalls or temporary brackets. This is more than a theoretical exercise.
RE: Maximum Bending Stress in a Pipe?
Let your acquaintances be many, but your advisors one in a thousand' ... Book of Ecclesiasticus
RE: Maximum Bending Stress in a Pipe?
Unless you have flexible connections, that seem to have enough give for this much movement (such as braided hose, bellows, or the like) at all the points; I'd tell them to suck it up and disconnect everthing, or they'll break something, and let them live with the consequences if they do.
RE: Maximum Bending Stress in a Pipe?
If you are concerned that something will go wrong, most likely it will! Murphy's Law is based on experience.
RE: Maximum Bending Stress in a Pipe?
so i guess my boss realized that the whole idea of calculating this is not really feasible because of the fact that there are so many pipes and so many variables, so theyve decided to disconnect all of them and not risk it. thanks for the help though everyone!