Ansys NGEN and EGEN Commands

The NGEN command is used to create a series of regularly spaced nodes from one or more existing nodes. Similary, the EGEN command is used to create a series of regularly spaced elements from one or more existing elements.

The NGEN command has eight options.

      NGEN, COPIES, INC, NODE1, NODE2, NODINCR, DX, DY, DZ

where

      COPIES=  total number of copies including the original
      INC=     node number increment between sets
      NODE1=   first node number of the original pattern
      NODE2=   last node number of the original pattern
      NODINCR= increment between node numbers in the pattern
      DX, DY, DZ=  the geometric translation vextor of each copy

For example, the lines:

      len = 1/20                ! pipe length
      nrows = 5                 ! number of element rows
      NGEN,(nrows+1),10,1,9,1,0,(len/nrows)

create six sets of nodes (nrows+1) using nodes 1 to 9 as a pattern. Each new set of nine nodes begins with a node number that is ten greater than the previous pattern. Thus, the second set of nodes is numbered from 11 to 19 and the last set is 51 to 59. Each set of nodes is placed a distance of 0.01 (len/nrows) in the Y direction from the previous set.

You can also define a sequence of nodes with the FILL command.

The EGEN command is used to create a series of regularly spaced elements from one or more elements made with the E or EGEN command. Similary, the EGEN command has three or more options.

     EGEN, COPIES, NODINCR, ELEM1, ELEM2, ELINCR   or
     EGEN, COPIES, NODINCR, -NUM

where

      COPIES  total number of copies including the original
      NODINCR node number increment between sets
      ELEM1   first element number of the original pattern
      ELEM2   last element number of the original pattern
      ELINCR  increment between element numbers in the pattern
     -NUM     number of most recently defined elements of the original pattern

For example, the lines:

      E,1,2           ! one element, 1-2
      EGEN,4,1,-1     ! 3 more elements, 2-3, 3-4, 4-5

create four linear elements, while the lines:

      E,1,2,12,11               ! lower-left square
      EGEN,4,1,-1               ! lower row of squares
      EGEN,5,10,-4              ! four more rows

create 20 quadralateral elements. One row of four elements is made by the first EGEN command and those four are copied to get a 4-by-5 grid in the second EGEN command.

MENG 421 -- Nodes and Elements -- Element-Property Tables -- Ansys index -- Class assignments