FEAP User Forum

FEAP => nurbFEAP => Topic started by: crepes on September 15, 2016, 06:54:08 AM

Title: User element for heat transfer in nurbFEAP
Post by: crepes on September 15, 2016, 06:54:08 AM

Dear feap developers and feap users,

I have been trying to learn how to create a user element in nurbFEAP.

The two dimensional heat transfer element, which is attached to the feap theory manual for feap 8.4, serves as a basis for my user element in nurbFEAP. I implemented this element successfully in normal feap and tested the user element using some input files.

To implement this user element in nurbFEAP I changed some things like for example the usage of shape functions in the fortran code of the element. I was guided by comparing the code of the existing elements in '.../ver84/nurbfeap/elements/' but my work seems to be unsuccessful, as my residual is zero in every time step while carrying out some tests.

So I guess i did not change all of the necessary things.

Is there a plan to publish a heat transfer user element for nurbFEAP, like you did while publishing the theory manual for normal feap? Having a working user element would be a great convencience to create my own user elements.

Title: Re: User element for heat transfer in nurbFEAP
Post by: Prof. R.L. Taylor on September 15, 2016, 11:34:17 AM

The existing thermal elements are supposed to work with NURBS.  did you try doing the thermal problem with a NURBS mesh and with a NURB command in the material data?

Title: Re: User element for heat transfer in nurbFEAP
Post by: crepes on September 15, 2016, 11:54:42 AM

Thanks for your answer, Prof. Taylor,

using

Code: [Select]

MATE 1
  THER
    FOURIER ISOTROPIC 10.0 1.0
    DENSITY MASS 0.10
    nurb interp 3 3
and using some nurb mesh works fine.

Does nurbfeap call the '.../ver84/elements/thermal/therm2d.f'? (Since there was no change in this file after installing the nurbs extension) I thought that nurbFEAP calls another thermal element, which I still have not been finding.

Title: Re: User element for heat transfer in nurbFEAP
Post by: Prof. R.L. Taylor on September 15, 2016, 02:16:33 PM

Displacement/thermal elements call standard feap ones.  Only quadrature and shape functions change

Title: Re: User element for heat transfer in nurbFEAP
Post by: crepes on September 16, 2016, 12:26:50 AM

Thanks for your help, Prof. Taylor