FEAP User Forum

FEAP => FEAPpv => Topic started by: bck230 on June 22, 2021, 01:23:36 AM

Title: Normal force from the surface of a cylinder-like structure
Post by: bck230 on June 22, 2021, 01:23:36 AM

Dear all,

My project is to use feappv to simulate the effect on the stent resulting from the impulse of the artery.
I want to apply an outward expanding force from all of the nodes on the specified z-plane.
What comes to my mind is to transform the Cartisian coordinates to cylindrical coordinates then use EFORce to implement it.
But I look up the manual and only find CYLIndrical which is to transform the coordinates from cylindrical to cartisian.
Is there any option to do the coordinates transformation or are there any better ways to define the forces?
Thank you for your help!

Best,
Ruei-Bo

Title: Re: Normal force from the surface of a cylinder-like structure
Post by: Prof. R.L. Taylor on June 22, 2021, 07:07:21 AM

In general, all the FEAPpv elements require final forces to be a Cartesian frame.  Thus if the loads are radial, you want to transform them all to have x,y,z components -- that is what the CYLI command will do for any radial forces.   If you need something more general then you need to write a user module to perform the operation.

Title: Re: Normal force from the surface of a cylinder-like structure
Post by: bck230 on June 24, 2021, 12:59:43 AM

Dear professor Taylor,

Sorry for the late reply.
I thought CYLI command could only transform the coordinates of nodes.
So I have to set up a radial load then use CYLI to transform the load into Cartesian frame.
But I have difficulty setting a radial load.
I thought RFOR could help me do that but then I found it's not what I want.
Is there any command like
EFORce
polar
at 3rd-axis = 0
r = force, theta = 0, z = 0?

Then I used CYLI to transform this kind of load in to Cartisian for feappv to solve.
This what I understand so far.
Please point out if I misunderstand anything.
I highly appreciate your advice and help!

Best,
Ruei-Bo