Shreyas Hoskere, M.S. University of Utah, May 2005
Analysis and objective evaluation of complex designs such as machine tools is
difficult to perform during the conceptual design phase. CoM-SiM is a 3D parametric
sketcher tool which aids an engineer to set up 3D sketches or 'stick figures'
of mechanical devices and mechanisms very quickly. The user can sketch the
mechanical design in CoM-SiM like sketching on paper.
All elements sketched
are idealized finite elements and their element type can be defined or changed
at anytime during the sketching process. All sketches are converted to FE
code readable by ANSYS FEA package. CoM-SiM has a 'materials' database and
section' database to apply appropriate properties to the sketched elements
when needed. To especially accommodate precision machine tool design, it
also contains a standard 'Ballscrew' and 'Bearing' database with built-in
stiffness calculators to allow sketching and evaluation of precision machine
their bearing and ballscrew systems.
The GUI is a menu and toolbar driven
interface which implements user inputs from a standard mouse and keyboard.
the Microsoft Windows platform and implementing smooth OpenGL graphic
libraries, the GUI incorporates a four-split window which displays a constantly
standard three orthographic views and a projection view of the 3D model.
The model can be sketched on any of the four views with seamless switching
views during sketching. All the sketching is directly drawn in 3D using
an innovative 'parallel to view plane' method.
The GUI also implements several
graphical cues to view the 3D (wireframe) sketches very intuitively.
The parametric 3D sketching allows existing concepts to be modified very
quickly in order
to explore different design configurations, making this tool much more
than a paper sketch.
|Modeling and analyzing a frame with four legs. The
video uses modeling across different views for fast modeling.
|Modeling a ball screw as a spring and assigning
properties from a database. Complicated mechnical elements such as ball screws, which
consist of a large number of rolling elements are simplified by a spring,
whose properties are assigned from a database.
|Modeling a bearing as a spring and assigning
properties from a database. Bearings a complex mechanical elements that consists of
a large number of rolling elements. In Com-Sim, a bearing is simplified
with a spring whose properties are assigned from a database.
|The sketch plane is automatically defined by
selecting a single point. In Com-Sim, the sketch plane does not need to be defined
explicitly. Instead, the sketching plane is automatically defined by selecting
an exisiting node. The sketch plane is then created that contains the node
and is parallel to the view orientation. If no node is selected, the sketch
plane goes through the origin and is parallel to the view of the window.
|Modeling and analyzing a 5-axis machine (Star
Tool Grinder). A complex machine tool sich as the STG (see
link for details)
can be greatly simplified in Com-Sim and analyzed using commercial finite
element software (e.g. Ansys).
E. Bamberg, S. Hoskere (2005). CoM-SiM - conceptual machine design
simplification modeler. In: Proc. 2005 Euspen Conf., Montpellier,
France, May 8-11, 2005 (2), pp. 417-420.