Steady State Flow - Programming the Finite Element Method - page 343

element nod nels nn nip ndim np_types
'hexahedron' 8 64 125 8 3 2

prop(kx,ky,kz)
2.0 2.0 2.0 1.0 1.0 5.0

etype
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

g_coord
0.0 0.0 0.0 1.0 0.0 0.0 2.0 0.0 0.0 3.0 0.0 0.0
.
g_coord data for nodes 5-120 omitted here
.
0.0 4.0 -4.0 1.0 4.0 -4.0 2.0 4.0 -4.0 3.0 4.0 -4.0
4.0 4.0 -4.0

g_num
6 1 2 7 31 26 27 32 7 2 3 8 32 27 28 33

.
g_num data for elements 3-62 omitted here
.

98 93 94 99 123 118 119 124 99 94 95 100 124 119 120 125

loaded_nodes,(k,loads(k),i=1,loaded_nodes)
1 21 100.0

fixed_freedoms,(node(i),value(i),i=1,fixed_freedoms)
61
1 0.0 2 0.0 3 0.0 4 0.0 5 0.0 10 0.0 15 0.0 20 0.0

.
fixed freedom data for 48 nodes omitted here
.
121 0.0 122 0.0 123 0.0 124 0.0 125 0.0

Figure 7.20 ( Continued from page 342 )

second group to elements 33 to 64, which are anisotropic with k x = k y = 5.

The etype vector then reads the information required to match elements with property
groups.
In this chapter we always assume that the principal axes of the permeability tensor
coincide with the Cartesian coordinate axes leading to a diagonal property array kay .If
this is not the case, the kay matrix will be fully populated with off-diagonal terms.
The next data involves the x , y , z coordinates of the nn nodes in the mesh read into
g coord , followed by the node numbers of each of the nels elements read into g num .
If dealing with a three-dimensional 8-node element for example, the order in which the
node numbers are read must follow the sequence described for that element in Appendix B.
Due to the volume of data required in this example, only a few lines of the g coord and
g num data are actually shown in Figure 7.20.
There is one source at node 21 equal to 100.0 indicated in the loaded nodes data. All
the outside faces of the cube are fixed to zero, which requires 61 fixed freedoms data.
If Program 7.4 is to be applied to a 2D analysis using 4-node quadrilateral elements, a
final data input of the number of contour intervals nci is also required.

1and k z =