hyper mesh application

1. Report
On
Meshing a mechanical component in
Hyper Mesh
By
P Venkat Vijay Kumar
09101291
Section 3A
Roll No. 18
Mechanical Engineering Department
KLUniversity
1

2. Machines have played a crucial role in transformation of man’s life. But many crucial
components make a machine. Therefore for effective simulation of machines and their working,
meshing the components plays an important
role.
Transfer of rotary motion from one shaft to
another is widely needed task to be able to
utilize machinery. Suppose a portable generator
driven by a four stroke single cylinder engine.
The rotary motion of flywheel of the engine has
to be transferred to the generator so that it
generates power in another form. Thus
couplings play an important role in machines.
A knuckle joint is used to connect the two rods which are under the torsion load, when there is
requirement of small amount of flexibility or angular moment is necessary. There is always axial
or linear line of action of load. Parts of a knuckle joint are
Fork end rod
Eye end rod
Collar
Pin
Tapper pin
Out of all the parts mentioned fork end rod is
a bit more complex, when compared to the
rest of them. Therefore meshing of the fork
end of rod is demonstrated.
Here are some views of the fork end
component, drawn and generated in Catia.
CATIA (Computer Aided Three-dimensional
Interactive Application) is a multi-
platform CAD/CAM/CAE commercial software
suite developed by the French
company Dassault Systemes. Written in
2

3. the C++ programming language, CATIA is the
cornerstone of the Dassault
Systemes product lifecycle
management software suite.
The component is generated by initially
projecting in sketcher and drawing it into 3d.
Actually any component is drawn that way.
Following are commands used.
Pad
Pocket
Grove
Edge fillet
Circular array
Now generated component is to be exported to Hyper Mesh for further steps. If you have the
Catia license in Hyper Mesh the geometry can be directly imported from Hyper Mesh import
option. If not the file generated in Catia as ‘*.catpart’ is converted into ‘*.iges’ and then
imported in HM.
Hyper Mesh
In Hyper Mesh the part is imported from selecting import option from the tool bar or ‘file >
import > geometry’ and select the component from its location.
Once the component is imported the model browser shows the
components as (1).
Edge check and geometry clean up
The first step should be check of unclosed edges and volumes
along with any errors in the geometry. The icon ‘visualization
option’ is selected from the Commands panel toolbars that opens
the visualization page. This page contains several colors showing
edges. If there are no free edges and all are shared edges the task
here is done. Usually using the current day software suites such as
Catia, ProE lets us get the exact shape without any data loss while
3

4. converting.
If any of errors found they are corrected by suppressing, equivalencing and redrawing certain
planes, surfaces, edges or points.
Some shapes may not be defined well at a required level they have to be readdressed by Hyper
Mesh. Autocleanup option in the geometry page is enough to complete cleanup of all surfaces.
All the surfaces are selected and autocleaned with given parameters.
Any more changes are done through the options available such as Quickedit, Edgeedit,
Pointedit, Solidedit, Surfaceedit, Defeature etc.
Meshing
Mesh generation is one of the most critical aspects of engineering simulation. A clean mesh
with appropriate densities has several advantages. If a load has to be applied over a region no.
of nodes there has to be known, a regular mesh
helps. And near the intricate regions higher
densities of elements would make the results
much better approximation.
Keeping the above mentioned in view we mesh
the component in two steps. In the first step we
mesh the surfaces and in second step, the volume
is meshed with reference to the nodes and elements formed from surface meshing.
First of all, the surfaces where there would be necessity of connecting, acted upon by loads are
to be meshed with as much regularity as possible. Selecting the inner surfaces of the circular
hole, a provision for pin is apt one here.
Therefore the two surfaces are selected and meshed from the panel shown in the figure.
Then each and every surface is selected individually and meshed using the same panel. By
meshing it individually we can control the quality of the mesh as needed. It is always better to
save meshed elements into a new component so that 2D elements can be deleted afterwards.
Now the quality of the 2D mesh is to be checked and corrected to possible extent. The image
shows quality index of the 2D mesh. The red elements are badly out of shape so they have to
be rebuilt or no. of nodes has to be increased or moved.
4

5. Now 2D elements are meshed into 3D form. Tetramesh option is found in 3D page and that
option is used to generate 3D elements. All the elements are selected and meshed into tetra
form.
Quality checking of the mesh
Now we have got the solid 3D tetra mesh. This can be checked by masking few elements and
see the other elements. Mask option is found in
the tools page. Select some elements by window
and mask them. To get back the elements
unmasking all is the option. Thus the entire
component volume is meshed. But now we don’t
know whether each element generated is perfect.
The options ‘check elems’ in tools page comes
handy here. Set the mode as 3D. And you can see
the following page.
Warpage 0% Failed Equia skew 9% Failed
Aspect 0% Failed Vol skew 9% Failed
Skew 0% Failed Vol AR 1% Failed
Tetcollapse 13% Failed Tria Faces min 1% Failed
Cell Squish 3% Failed Tria Faces max1% Failed
Length 0% Failed Quad faces min 0% Failed
Jacobian 1% Failed Quad faces max 0% Failed
5