SIMULATION MODEL
USING THE RIGHT COMPUTER
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ABSTRACT
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Using simulation and virtual prototyping to design a new engine concept with the desire to achieve better and faster results with reduced or no physical testing, a team of two engineers at US Army Tank Automotive and Armament Command (TAACOM) set out to build the "opposed pistons or quadruple" engine. Simulating new machines helps managers, decision-makers and engineers better understand the equipment. This paper describes how engineering application software coupled with fast processor hardware is generally required to fully understand the equipment.

THE PRESENTATION
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TAACOM's Rapid Prototype team was asked to build a solid model and develop a simulation model that will help the Propulsion team to analyze a newly proposed opposed pistons engine. This simulation model will help evaluate the design and operation of the engine prior to physically building it.
After describing the engine's proposed functionality, each of its parts was geometrically modeled using the 3D CAD Engineering Modeling System (EMS). Upon completion of the CAD modeling process, the CAD models previously created in EMS as geometric entities composed of lines, arcs, curves, circles, edges and surfaces were transferred into Denenb's IGRIP simulation program and converted to part geometry based on polygons.
After porting all related CAD models into IGRIP, the analytical work of building an intelligent system that clearly describes the functions of the engine was started. The CAD modeling was done on the Intergraph 6000 computer that was used later when developing the IGRIP model. It didn't take long to discover that the Intergraph 6000 machine is not equipped to effectively run graphical simulation files. Mechanism joint velocities, acceleration, deceleration, etc., are incorporated to complete the definition of an IGRIP device. All devices put together will make the engine model. Graphical representations of the parts motion tend to slow as more devices are built into the final model. Generally, the display of some parts in transparent mode is particularly handy for showing parts covered by other parts. But there was no transparent rendering when the display mode of the exterior housing engine model was changed to the transparent mode . Later, When the same IGRIP model was run on a Silicon Graphics' Onyx machine, the motion graphics and the display manipulation did not react in the same manner, and the two problems were solved.

CONCLUSION
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The success of the computer simulation is tied to using the right software and hardware systems. It is very difficult to deliver a better understanding of the model when the simulation is run on a computer not intended for this purpose.

ABOUT THE AUTHOR
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Jad Elghoul holds master's degree and bachelor's degree in Industrial Engineering from Wayne State University. He is an associate at TAACOM.