Archived pipe elements PIPE16 and PIPE18 are described in Part IV: Archived Elements.

*deck,usflex                      USERDISTRIB
      subroutine usflex (etype,elem,rvrm,kff,prs,ex,  flexi,flexo)
c *** primary function:   to (re)compute the flexibility factor 
c                           for pipe16 and pipe18
c                         this is accessed by inputting the flexibility factor
c                           as any negative number.
c *** secondary functions: none
c
c *** Notice - This file contains ANSYS Confidential information ***
c
c         *** Copyright ANSYS.  All Rights Reserved.
c         *** ansys, inc.
c
c     typ=int,dp,log,chr,dcp   siz=sc,ar(n)   intent=in,out,inout
c
c  input arguments:
c     variable (typ,siz,intent)    description
c     etype    (int,sc,in)       - pipe element type (16 or 18)
c     elem     (int,sc,in)       - element number
c     rvrm     (dp,ar(*),in)     - real constants
c     kff      (int,sc,in)       - keyopt for flexibility factor
c                                    (not used for pipe16)
c     prs      (dp,ar(5),in)     - pressures
c     ex       (dp,sc,in)        - young's Modulus
c     flexi    (dp,sc,inout)     - effective in-plane flexibility factor
c     flexo    (dp,sc,inout)     - effective out-of-plane flexibility factor
c                                    (not used for pipe16)
c
c  output arguments:
c     variable (typ,siz,intent)    description
c     flexi    (dp,sc,inout)     - effective in-plane flexibility factor
c     flexo    (dp,sc,inout)     - effective out-of-plane flexibility factor
c                                    (not used for pipe16)
c