Axial Force from Vertical Movements

Posted by: diegosurf82

Axial Force from Vertical Movements - 01/18/10 08:07 AM

hi guys,

I would like to make a question:

I've modeled a pipe in cantilever configuration and imposed movements on perpendicular direction respect to pipe path, on the free extreme.

I've noticed that it find out (as awaited) moment and shear forces but, appearently with no explanation, it doesn't show any axial forces on each extreme.

anyone would please explain thi to me?

thanks to all


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Hi Dave,
thanks for you quick reply.

I've simplified my situation for quick understanding, but the routing of line is different from ideal path.
I have one end with anchor, then two hinge restraints, and on the other end, I have fixed all rotation and translation, apart for movements tha I impose.

Same answer?

I try to send .C2 file.

Thanks in advance


Posted by: Dave Diehl

Re: Axial Force from Vertical Movements - 01/18/10 08:37 AM

The simple beam formula, used in these piping programs, does not include the constraint that, as the beam is moved off its axis, that one end of the beam must rotate about the other.
The global stiffness matrix which represents this pipe is based solely on the original position of the pipe. If I put a small, off axis deflection on one end, it moves is a linear fashion, it does not follow an arc. Same with a large deflection.