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Copyright © 1999 Adams Business Media, Inc. Would You Like A Reprint of
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CAD/CAM Software Helps in Race to Build Olympic 2000 Train
Designing a double-decker vehicle requires a model of up to 95 megabytes, all of which must be available at once. Clyde decided to design parts in solids, which are then used as referenced parts by other engineering disciplines. Helix enables this collaborative engineering to function properly; the referenced parts are active in order for the information to be available to all engineers. "The Interior Fit group, for example, will have the external structure to reference as both are under design," explains Phil Egans, Clyde's draftsman. Clyde is designing the 4GT train to be 100% electric (vs. diesel electric). "These trains are comprised of a set of four-coupled vehicles," says Reginold Gragham, Clyde's project manager. "Two of the set's units are equipped with drive motors and two lead/end unit trailers. As passenger capacity loads increase, another set of four will be added to the train," he explains. These train set/groups are run backward on the return trips to avoid reversing, switching or roundtable times. Clyde's 4GT is, therefore, streamlined on both ends. Streamlining the lead/trailing cars will be accomplished with surfaces, a feature of Helix solids. Rather than reverse engineer using 3D points from a physical mockup, Clyde engineers chose to generate surfaces using control splines to create the surfaced model defining the new body style. These shapes are then used to generate patterns, which are dropped off automatically in associative 2D cross-sections for manufacturing. One challenge was the extraordinarily large mold needed for the windscreen glass area. More complex surfacing is also being utilized for some stylized, doubly-curved surfaced regions in the coach interiors, around the staircase. Helix's kinematics function will allow Clyde to study the interaction of the wheels, bogies, torsion suspension, and anti-roll bars with the coach bodies. "Clyde has designed self-steering trucks on larger prime movers, and we would like to use kinematics motion to study these types of mechanisms," according to Egans. Interior designers at Clyde use standard construction tools included with the modeler for solid shapes in defining the seat cushions. Outfitters can also use kinematics to test the seatback motion required for reversing the train. The structural strength for a double-deck car pushes the envelope for achieving required strength and load carrying. The 4GT must stay within the weight limit, yet still have crash worthiness. These constraints are accomplished with high levels of energy absorption in body zones required by the customer's specification. "The life cycle of a light rail train package is about 25 years," says Tim Kajons, structural analyst at Clyde, "so we have to understand fatigue life and crack propagation." Mechanical stress and fatigue analysis is being performed with solid models on the 4GT coach structure and bogie parts passed from Helix in IGES format to the stress group. --RM For more information, contact: MICROCADAM, Inc., 2255 Ontario St., Suite 300, Burbank, CA 91504. helix@micro cadam.com. 800-423-2381. Circle 420. Clyde Engineering, Factory St., Granville NSW 2142. Tel. 02 682 9405. Circle 421. Copyright © 1999 Adams Business Media, Inc. Would You Like A Reprint of
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If you think you have a Y2K deadline to
meet, consider the challenge for Clyde Engineering, Ltd., Granville, NSW.
The company is endeavoring to engineer the next generation people mover
that, if finished in time, will carry athletes and visitors from the Sydney
airport to the Olympic village for the 2000 Olympic games. The pressure
is on, as plans call for the next Olympics to be a uniquely auto-less event.
When Clyde needed a productive
design software that could translate alien data and keep training time to
a minimum, the design team chose Helix 98 solid modeling software from MICROCADAM,
Inc., Burbank, CA, to produce the 4GT (Fourth Generation Train). National
suppliers furnish door systems to Clyde, as well as to local fabrication
shops charged with producing molded parts. Alsthom in France, supplier of
the traction units, sends Clyde current designs electronically via the IGES
format. The train's airbrakes are supplied by Knorr in IGES and STEP file
formats, which are being designed in Prime MadusaĆ. This has prompted
Clyde to adopt new standards for sharing 3D data.