5
EXAMPLES
5.0
OVERVIEW
You will find several
examples in this chapter along with their respective input files B*.* on the
Z88 diskettes. The examples 4, 6 and 7 can be calculated analytically by hand.
Work with the examples
which resemble your own applications. Also look at the protocol files *.LOG
produced by the Z88 modules. Plot the various examples and results on your
plotter or your laser printer capable of HP-GL. Vary the input files,
especially the mesh generator-input files for the examples 1, 5 and 7. Doing so
gives you a smart feeling for the howtos of Z88 very quick.
If examples won’t run, first search for memory problems. Are
there any other programs in the computer's memory, especially those fat and
greedy memory eaters like office packages? All examples were tested on various
computer equipment and operating systems, and all examples do run even on
oldfashioned computers with Windows 95. Additionally, Z88 is running very large
structures on SUN and SGI UNIX machines or modern PCs without any problems. The
largest structure computed with Z88 up to now featured 2.6 Mio. DOF and was run
on a 64 Bit PC with 64 Bit LINUX. If necessary, adjust Z88.DYN. Investigate the *.LOG files: It is
shown here if Z88 modules run out of memory. UNIX: Check file and directory
permissions.
After you have investigated
the ready-to-run examples, try to draw the examples in your CAD program. Export
to DXF files and convert them into Z88 files. If the CAD converter does not convert your DXF files
properly, then redo the steps 3 and 5 of chapter 2.7.2. Did you
"snap" the points cleanly ? If nothing works try another CAD program.
If you’v got a 3D CAD program
with an integrated automesher you may export FE meshes to COSMOS or NASTRAN
files and read these files into Z88 with Z88G. Check the amount of needed memory
and the quality of the nodal numbering by running Z88F in test mode. Renumber
with the Cuthill McKee programm Z88H, if nessesary. Or, even better, use the
iteration solver.
Example
1: Fork wrench.
Plane stress problem with Serendipity Plane Stress No.7 and mesh generator use. Learning
objectives: CAD and mesh generator use at curvilinear plane structures,
displaying stresses in the plot program. This example is fixed on the Z88
diskette ready to run as the first introduction example with Z88X.DXF,
Z88I2.TXT and Z88I3.TXT.
Example
2: Crane truss.
Modelled with Trusses No.4.
Learning objectives: Use of the different views and rotation possibilities in
space within the plot program.
Example
3: Transmission cam. Cam with different diameters, forces and moments in different planes
with cam
elements No.5,
statically overdefined. Learning objectives: Use of the cam elements,
especially for the boundary conditions at finite elements with 6 degrees of
freedom per node, use of the different views in the plot program.
Example
4: Beam in plane, repeatedly statically overdefined. On both sides firmly fixed Beam No.13. Learning objectives: Use of Beams
No.13, choice of the boundary conditions and the interpretation of the results.
Example
5: Disk segment in cake form.
General spatial problem with Hexahedrons No.10 (20 nodes) as super elements and mesh
generation of Hexahedrons No.1 (8 nodes). Learning objectives: Use of the mesh generator at
curvilinear spatial elements, showing stresses, different views and spatial
rotation possibilities in the plot program. After running this example
successfully it is a nice idea to make the mesh generator generating
Hexahedrons No.10 instead of Hexahedrons No.1, what is just a breeze. But you
must define new nodes for the boundary conditions.
Example
6: Pipe under inner pressure of 1,000 bar. Axially symmetric problem, solved as plane
stress problem with Plane Stress Elements No.7. Learning objectives: Clever use of
symmetry qualities of a structure and choice of the proper boundary conditions
and surface loads, showing stresses
in the plot program.
Example
7: Press fit.
Axially symmetric problem with Tori No.8 and use of mesh generator. Learning
objectives: Work with torus elements, use of the mesh generator with mesh
compression, stress display in the plot program.
Example
8: Crankshaft.
Space structure with Tetrahedrons No.16. Learning objectives: Starting with a COSMOS
file from Pro/ENGINEER, we will use the COSMOS converter Z88G, the Cuthill-
McKee program Z88H and both the solvers, i.e. the direct Cholesky solver Z88F
and the iteration solver Z88I1/Z88I2. This is an example for a FEA structure
imported from a CAD system.
Example
9: Rectangular plate with 16 nodes Lagrange plate elements No.19. Learning objectives: Starting with
an AutoCAD drawing for a super structure with plates No.20, we'll export the
DXF file to the CAD converter Z88X. Running the mesh generator Z88N will
generate a mesh of plates No.19. The system will be solved by the iteration
solver.
Example 10: Piston of a diesel engine with Tetrahedrons No.16. Learning objectives: Starting with
a NASTRAN file from Pro/ENGINEER, we will use the COSMOS converter Z88G, the
Cuthill- McKee program Z88H and the iteration solver Z88I1/Z88I2. This is an
example for a FEA structure imported from a CAD system using the surface and pressure
loads file Z88I5.TXT.
Notes: