NESC0765 ZONE

1. NAME OR DESIGNATION OF PROGRAM:  ZONE

3. DESCRIPTION OF PROBLEM OR FUNCTION

The ZONE program is a finite element mesh generator which produces the nodes and element description of any two-dimensional geometry. The geometry is divided into a mesh of quadrilateral and triangular zones defined by node points taken in a counter-clockwise sequence. The zones are arranged sequentially in an ordered march through the geometry. The order can be chosen so that the minimum bandwidth is obtained. The mesh that is generated can be used as input to any two-dimensional as well as  any axisymmetrical structure program.

4. METHOD OF SOLUTION

The basic concept used is the definition of a two-dimensional structure by the intersection of two sets of lines which describe the geometric and material boundaries. A set of lines called meridians define the geometric and material boundaries and generally run in the same direction. Another set of linear line segments called rays which intersect the meridians are also defined  at the material and geometric boundaries. The section of the structure between successive rays is called a region. The ray segment between any two consecutive ray-meridian intersections or void area in the structure is called a layer and is described as passing through, or bounding a material. The boundaries can be directly defined as a sequence of straight line segments or can be computed in terms of elliptic segments or circular arcs. A meridian  or ray can also be made to follow a previously-defined meridian or ray at a fixed distance by invoking an offset option.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The following are limited only by a DIMENSION statement. The code currently has a maxima of -
   100 coordinate points defining a meridian or ray
    40 meridians
    40 layers
There are no limits on the number of zones or nodes for any problems.

6. TYPICAL RUNNING TIME

The sample problems took less than one minute to execute.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

The output from ZONE serves as the  input file to NAOS, HONDO (NESC Abstract 672), and other axisymmetric finite element programs. The PLOT program is a post- processor for ZONE used to generate the graphical display of the geometry for LLL TV Monitor Display System viewing on hard copy.

10. REFERENCES

Michael  J. Burger,  ZONE  -  A Finite  Element  Mesh
Generator, UCID-17139, May 1976.

11. MACHINE REQUIREMENTS:  8 output and scratch files are used.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   SCOPE.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

   The
program assumes that the system clears the memory to zero prior to problem execution. Dummy routines are included in the package in place of LLL system environment routines.

15. NAME AND ESTABLISHMENT OF AUTHOR

                 M. J. Burger
                 Lawrence Livermore Laboratory
                 P. O. Box 808
                 Livermore, California  94550

File name	File description	Records
NESC0765_01.001	SOURCE	2692
NESC0765_01.002	S.P. INPUT 1	52
NESC0765_01.003	S.P. INPUT 2	121
NESC0765_01.004	S.P. OUTPUT 1	412
NESC0765_01.005	S.P. OUTPUT 2	809