Conflict in the name of subroutine rshp3d and shp3d

[riadefreemind]

Dear All
i want to ask whey in the Purposed Quadrilateral membrane element for feap (membr3d.f) in the elements folder of feappv : the name of subprogam used to calculate the Form shape functions and their integrals is called as: rshp3d as it shown in attached picture, while the called subroutine existing in the program folder of feappv is named: shp3d ?

[Prof. R.L. Taylor]

I do not know which shp3d.f you are referring to?

The membrane element was developed from a shell element by removing the bending and shear parts, the shape function routine was not changed

[Prof. S. Govindjee]

subroutine rshp3d( ) can be found in elements/shells/shell3d.f

[riadefreemind]

thank you

[riadefreemind]

also, i want to know if this Form 4-node quadrilateral shape functions: are based on the stain approach or the displacement approach ?

[Prof. R.L. Taylor]

I do not know what you mean by "strain" approach vs "displacement" approach?

The 'rshp3d' routine is for a very specific formulation of shells which was done more than 30 years ago.  I do not currently have access to the reference (which was a conference book publication) and do not remember all the details.  There I believe the basic form is for a hierarchic Serendipity 8-node formulation that is used to get the DKQ form -- but that may not all be correct.  Sorry to not be able to help you more.

What are you trying to  use the routine for?  If you want the usual shape functions for finite elements look at the ones in the 'program' directory.  shp2d.f is for 2-d and shp3d.f is for 3-d problems that are C_0.