Software bridges the global
Tools allowing easy data sharing are crucial for
manufacturers hoping to take advantage of brain power around the
As international collaboration among engineers becomes increasingly common,
software tools are playing an ever-more-crucial role in the ability of
manufacturers to share resources and data across national boundaries.
Jet-engine manufacturer BMW Rolls-Royce GmbH (Oberursel, Germany), for example, draws on the resources of its German- and UK-based parent companies. Though BMW Rolls-Royce has 800 engineers at its Dahlewitz, Germany, development and assembly center, it also relies on the expertise of engineers located in Frankfurt, Germany, and Bristol, UK. And, the company takes advantage of finite element analysis and other test programs in place at its UK parent.
BMW Rolls-Royce is also developing an extended enterprise network through two prototype hook-ups--one to Rolls-Royce's Bristol offices, where engine externals are constructed; the other to Belfast-based Short Brothers plc, builder of engine-support equipment. The ultimate goal: implement an environment that will facilitate transparent collaboration on a global scale with partners, suppliers, and customers.
BMW Rolls-Royce contracted with Computervision Corp., Bedford, MA, to develop this worldwide communication network. Chris Amoah, EDM project leader for BMW Rolls-Royce, cites Computervision's CADDS® 5 as an important element in the network. Not only is the software compatible with test and analysis programs, it creates and is compatible with many modeling formats.
Enterprise Data Management (EDM) software is responsible for storing, tracking, and managing all engineering-related design documentation. Currently, more than 400 BMW Rolls-Royce engineers are using it, and that number increases every day, says Amoah. "EDM can track and manage even non-CADDS 5 data, and that will give us valuable flexibility as we add partners to our growing enterprise network," he adds.
Three EDM information storage repositories, or vaults, are located in Frankfurt, Dahlewitz, and Bristol. Engineers typically work on "in-progress" designs at their local vaults. Once releasedfor public view and use, designs are copied to all three vault locations. The result: network traffic is minimized, and a triple-redundant back-up scheme is enforced.
EDM's distributed logic also adds geographical transparency: any authorized engineer can find data located on non-local vaults simply by switching from the local, default vault to the other two. "This is beneficial because our engineers tend to move around," says Amoah, "so they are able to maintain relatively easy access to pre-release drawings that might be stored at other locations."
Security is another important feature of the BMW Rolls-Royce EDM implementation. "Network security features an extremely secure sign-on procedure, yet it doesn't get in the way of performance," says Amoah. One example: BMW Rolls-Royce regularly transfers large data files back and forth to Short Brothers in less than 30 minutes, something that took five days before the EDM network was installed.
BMW Rolls-Royce anticipates greater benefits in the future. "The software helps us compete right now, but it also makes us increasingly competitive in the future by capturing--and leveraging--the knowledge we possess, and the knowledge we expect to attain," says Amoah.
A competitive edge. Relying on a development team scattered across the globe isn't unusual for Redwood City, CA-based Verifone Inc. either. In fact, this manufacturer of transaction automa-tion equipment wouldn't have it any other way.
"We try to go where our 'IQ points' are," says Roger Hall, manager of Verifone's mech-anical engineering department. "Traditionally, we've had a stronger packaging design group in Taiwan, so if an enclosure is complicated, we want it designed there. But our strengths in software engineering and printed-circuit-board technology are somewhere else, so those aspects of the product are handled at other sites." Using this global approach, Verifone has cut its development cycle to as little as seven months for some products. The key to making this decentralized global development, manufacturing, and services approach work, says Hall, is a communication system that includes a computer network, video conferencing, and I-DEAS Master SeriesTM software from Structural Dynamic Research Corp., Milford, OH.
"While the computer network and video conferencing meet some of our needs, we rely on a solid model as our main means of communicating on the mechanical and industrial design side," explains Hall. "That's because a solid model is an unambiguous representation of design intent. Our engineers can send their files to anyone, anywhere and be certain they are understood."
When Verifone develops a new transaction automation system, the company's Redwood City facility initiates all the CAD work. "We produce an I-DEAS file that defines the exterior contours of the product and some of the internal structure," says Brian Drugge, industrial design manager at Redwood City. The file is then accessed by mechanical, electronic, and software engineers around the world who complete the design.
According to Hall, staying competitive requires a strong solid-modeling tool and the ability to manage data so remote sites can access it with a minimum of effort. By serving as a single source of product design and intent, and allowing Verifone to leverage its solid models in downstream applications, I-DEAS has helped significantly reduce the product- development cycle, he says.
I-DEAS also helps Verifone engineers take advantage of the time difference between sites. When someone needs a change made to a design, he or she sends a design service request over the network. If the request is urgent and arrives at the end of a work day, the person receiving it can pass the message along to an engineer in a country where it is earlier in the day. That person can immediately access the I-DEAS files, make the changes, and send the design back to the person who put in the request.
That kind of turnaround, possible through a global system for sharing information, company officials say, is one of the key reasons behind Verifone's success.
--Deana Colucci, Associate Editor
Polyester endows oven with a cool touch
St. Florent sur Cher, France--A Sologne wall oven developed by the Rosières company features a seamless one-piece oven door frame and control panel that combines sleek styling and a cool touch. It also costs less to produce than previous models.
Injection molded from a thermoplastic polyester resin, the frame/panel is said to be the first one-piece unit of its kind. The innovative module, made from Rynite® PET from DuPont Engineering Polymers, Wilmington, DE, includes a one-piece handle and two side pieces.
Each of the molded components replaces several metal parts. "The design saves on assembly costs and reduces the number of seams to collect dirt and grease," says Ted Butherus, appliance industry development manager for DuPont. "The clean, seamless look provides sales appeal; and, unlike metal parts, the integrally colored parts require no costly painting, plating, or other surface finishing. The parts are also cooler to the touch than metal because of the material's lower heat flux."
Rosières' components are made in appliance white and black from a color-stable Rynite formula specially developed for parts exposed to higher temperatures. The resin keeps its original color for more than 1,000 hours at 160C, says Butherus, and can operate at peak temperatures of 200C.
Composite yoke debuts on commercial helicopter
Fort Worth, TX--Engineers at Bell Helicopter Textron have created the first commercial rotor-blade yoke assembly made from fiberglass. Constructed completely from S-2 Glass® (Owens Corning, Toledo, OH), the dual yoke assemblies on the Bell 430 helicopter recently received certification from the TCA (Transport Canada Aviation).
The yoke caps a new four-bladed, bearingless composite rotor system. Attached directly to the helicopter's mast, it accommodates the blades' cyclic flapping and feathering motions. Engineers designed the yoke in a new shape to eliminate bearings that normally withstood the blades' torsion load. "This one serves a dual purpose," says David Sims, Bell's chief of materials and processes. "Not only does it take bending and chord loads, it takes the twist out." Fewer bearings means lower maintenance and extended life.
Traditional titanium or steel yokes lasted about 5,000 flight hours. But the glass-fiber-reinforced version is expected to endure several times that--and provide improved safety, as well. "If you get a crack in a metal yoke, it doesn't take many cycles to fail the part," Sims explains. By contrast, fiberglass produces a part that is much more tolerant of damage. "It's very forgiving; you can actually shoot holes in it and it will still hold the load," he says.
Though used on military rotorcraft for years, this is Bell's first commercial composite yoke assembly. Sims selected S-2 Glass after careful consideration of materials such as E-glass, carbon fiber, and Kevlar. In the flexible yoke, S-2 Glass's greater elasticity actually produces lower stresses than carbon fiber. And though the fiberglass part costs a bit more than metal, its longer life, improved safety, and elimination of corrosion make it a less expensive option overall. Says Sims, "All our new designs are going to composite rotors."
--Mark A. Gottschalk, Western Technical Editor
Student awards take on Teflon
Wilmington, DE--What do a surface coating for small-area flexible printed circuits; use of membranes of amorphous fluoropolymers to separate gases and vapors; and a self-lubricating, wear-resistant ceramic for machine parts have in common? They were all winning entries in the 1996 DuPont Plunkett Student Awards for Innovation with Teflon®.
Jennifer Alexander, a senior chemistry student at Colorado State University, walked off with the top prize. She proposed a new low-tear, less-corrosive surface coating for small-area flexible printed circuits (FPCs). The circuits must fit into areas so small that they are sometimes folded. FPCs are critical to the manufacture of such products as cameras, calculators, computers, printers, communications equipment, and space-vehicle components.
In her award writeup, Alexander stated: "This entry proposes an entirely new use for the Teflon AF line of fluoropolymers. My entry takes full advantage of the chemically inert properties which make Teflon fluoropolymers unique." She proposes using Teflon as an areal-selective surface modification to protect FPC surfaces.
Second prize went to Anuraag Sigh of North Carolina State University. His concept uses membranes of Teflon AF amorphous fluoropolymers to separate gases and vapors under chemically challenging process conditions.
Sigh reports that the Clean Air Act of 1990 makes it imperative that volatile organic substances be eliminated or reduced in volume. The concept would help bring this about by using Teflon AF 1600 and AF 2400 membranes. The system would reportedly recover more than 80% of the fluorocarbons from the feed, leaving a purified residue containing about 90% fluorocarbon, and a permeate stream comprised of greater than 99.5% H2.
Third prize went to a team from the Colorado School of Mines that proposed self-lubricating, wear-resistant ceramic for machine parts.
The team's procedure involves the use of an aqueous dispersion of Teflon to place controlled layers of the polymer on the ceramic surface and "roughen" the polymeric surface. A layer of ceramic or metal would be added to the composite to form a semi-protective layer shielding the Teflon from abrasion and wear. The final product would have a morphology of pools of Teflon in a field of ceramic or vice versa.
Launched in May 1993, the competition has continued to generate broad interest throughout academia. Students were matched with a fluoropolymer industry expert.
Plastic washers boost bus transmission performance
Hofheim, Germany--A transmission system de-veloped for leading European bus manufacturers features thrust washers molded from a high-performance aromatic polyketone polymer. Compared to traditional nitrided metal washers, the plastic washers in the fully automatic Ecomat transmission offer considerable wear reduction and a lower coefficient of friction. In addition, the molded washers have demonstrated long service life in the demanding local-bus transportation environment.
ZF Freidrichshafen developed the transmission in cooperation with Victrex GmbH, a division of Victrex plc., and Joma-Polytec GmbH, a custom injection molder. Local transit buses made by Daimler Benz, Volvo, RVI, Scania, and MAN use the transmissions.
To operate in this severe setting, each of the Ecomat's planetary gears include six central thrust washers of various diameters molded from the aromatic polyketone polymer. The material selected: VICTREX PEEK 450FC30 resin, a friction-modified bearing grade filled with PTFE, graphite, and carbon fibers. The polyetheretherketone was supplied by Victrex USA Inc., West Chester, PA.
The transmission maker specified the material for its low coefficient of friction, high wear resistance, compatibility with lubricants, and mechanical strength at high temperatures, according to Marianne Morgan, Victrex's transportation market manager.
Due to the fact that the PEEK resin can be easily injection molded into precision parts, the washer design incorporates such features as oil grooves, lubrication pockets, and centering details.
"The operating environment for these transit vehicles is a demanding one," says Morgan. "The continuous stops and starts of city traffic require driving in low gear at up to 3,500 rpm. This creates high temperatures and the potential for considerable mechanical wear. This grade of PEEK not only meets initial specifications, but it does so over a very long service life--a minimum of more than 300,000 miles."
Award sponsors help highlight excellence in engineering
Newton, MA--As the Design News Engineering Awards begin their 10th year, leading OEM suppliers are once again stepping up to show their support.
As it has for the past nine years, the Torrington Co., Torrington, CT, is leading the way with $20,000 for the Engineer of the Year award. The award honors a distinguished engineer chosen by Design News readers. The 1996 honoree: Alan Mulally, senior vice president of airplane development and definition at The Boeing Co., Seattle, WA, who had overall responsibility for the company's new 777.
"Our long-term commitment to the Engineering Awards program represents our belief in the critical role of technical innovation--and in our own business and industry in general," says Milanne DiElsi, marketing communications manager, The Torrington Co. "Our engineering grant recognizes outstanding individual achievement while providing special support for the technical education that makes such accomplishment possible."
For the seventh consecutive year, NTN Bearing Corp., Des Plaines, IL, is sponsoring a $15,000 grant that is donated to a college specified by the winner of the Design News Special Achievement Award. The magazine's editors choose the honoree based on outstanding lifetime achievements in the engineering field. The 1996 recipient, John Hench, supplied the vision behind many of the attractions designed by Walt Disney Imagineering, Glendale, CA.
"We are proud to sponsor the award as one of our efforts to encourage young people to enter the engineering profession," says George Hammond, president of NTN Bearing Corp. "We believe that there will be a need for many dedicated and resourceful engineers in the future. Someone must tell the generation now in grade school about the opportunities and satisfaction of a career in engineering."
The Engineering Quality Award is being backed for the eighth year by Schneeberger Inc., a producer of precision bearings based in Bedford, MA. Last year's winner, Curran Cotton, vice president of research and development at the Maytag Corp., Newton, IA, is the man behind the well-known and "dependable" products the company produces. Schneeberger will donate the $15,000 grant to the school of the 1997 winner's choice.
"The program sheds light on engineers who serve as role models for our next generation of innovators and high achievers in a discipline vital to every economy," says Andy Fischer, Schneeberger's executive vice president and managing director. "We hope to assist in establishing this event as the 'Oscars of Engineering' and thus further increase the visibility for an exciting profession."
This year The MacNeal-Schwendler Corp., Los Angeles, CA, will provide three $5,000 prizes for the Grand Prize winners of the Excellence in Design contest, moving up from the company's 1996 $10,000 contribution to the Design News Engineering Foundation.
"By supporting programs such as the Design News Awards, we are helping to ensure that students in our engineering schools receive the education that can lead them to imagining their possibilities," says Thomas Curry, president and CEO of MacNeal-Schwendler.
A new edition to this year's lineup is the Excellence in Computer-Aided Design Award. It honors the lead engineer of an outstanding new product whose success can be traced in large part to PC-based computer tools--both hardware and software.
The winning engineer will receive a $5,000 prize and will designate an engineering school to receive an additional $5,000 grant. Microsoft Corp., Redmond, WA, will fund both the prize and the grant. "We thought it was time to give credit to the millions of engineers and designers who are creating products on PCs," says Matt Ragen, worldwide marketing manager for the engineering and mapping industries at Microsoft.
Second-place in the Excellence in Design competition, now in its 17th year, will be supplied by Bose Corp., Framingham, MA. The firm will donate four of its Acoustic Wave stereo systems to the winners.
Finally, Edmund Scientific Co., New York, NY, has donated five Astroscan telescope packages to the third-place winners in the Excellence contest.
Most of the awards will be presented at the annual Design News Engineering Awards banquet in Chicago in March of 1997. The event is held in conjunction with the Annual Design Engineering Show at National Manufacturing Week.
"Our awards program seems to get bigger and better every year," says Design News Publisher Larry Maloney, "and it's the generous support of our sponsor companies that makes it all possible."
Civic continues smooth tradition
Newton, MA--From behind the wheel, you can tell the new Civic is a Honda even with your eyes closed. Fluent, nearly silent, and ultimately drivable, this redesign follows the trajectory started with the first Civic in 1973: it just keeps getting better.
New styling features include a larger speedometer, narrower C-pillars, and rear quarter windows for better visibility. Most drivers will appreciate dual airbags, stiffened body panels, and more responsive braking.
Honda engineers decreased the Civic's brake-pedal ratio for firmer pedal feel and shorter travel. For models equipped with ABS (standard on the EX sedan and optional on the LX sedan and EX coupe), engineers modified the disc/drum system to make it more affordable. The new system's modulator is about 30% lighter and half the size of the previous version. Each front-wheel sensor has a separate channel to the electronic control unit, but the rear wheels share a third channel, meaning rear-wheel slave cylinders act in unison to prevent wheel lock-up.
Under the hood, a 1.6l die-cast aluminum-alloy engine block and new porting contribute to the Civic's impressive LEV (low-emission vehicle) rating. With a slightly thicker, shorter skirt and other modifications, the new piston design weighs 7.3% less than the previous design. A lower reciprocating mass yields better reliability, increased rpm range, and less vibration, say engineers.
Honda created a new intake port that boosts swirl during the compression and ignition strokes. The result: cleaner, faster fuel burn and better efficiency--to the tune of 36 mpg on the highway for the LX model Design News drove.
If you're thinking about the road ahead and not the exhaust behind, the Civic won't disappoint. A lowered roll axis lets the Civic cling to curves, and new Grade Logic Control smooths shifting in the automatic transmission. Look for a continuously variable transmission later this year.
--Andrea Baker, Associate Editor
Intergraph doubles graphics performance
Huntsville, AL--Intergraph Corp. says off-the-shelf components and industry-standard architecture help it deliver more graphics bang for the buck compared with RISC/UNIX workstations. "We're leveraging the PC market to get the costs down," says J. David Farmer at Intergraph.
The company's latest TDZ 3-D graphics workstations use one, two, or four Pentium Pro processors, and feature built-in 100-Mbit/sec Ethernet networking. And, Intergraph's new RealiZm graphics system is the first to offer 2.5 million triangles per second, Farmer said. This more than doubles the performance of Intergraph's previous generation of graphics while shrinking the subsystem from a deskside tower down to a single board.
One animation demo that took 12 minutes on an older system ran in just 6 seconds on the new TDZ. "I think this technology is going to change the mechanical design process," Farmer says, allowing engineers to work on more complicated models interactively.
Three different graphics configurations--the Z10, Z13, and Z25--feature from 1 to 2.5 million triangles per second, with optional texturing and geometry acceleration.
The RealiZm graphics system is a 2-PCI-card set bundled together as a single board. It uses three different types of custom-designed chips--for the bus, main geometry-acceleration engine, and memory interface. The largest ASIC, for graphics acceleration, features more than 400,000 logic gates and presented special design challenges because of its size, company officials say.
To deal with the different heat-expansion properties between the packaged chip and the board it sits on, engineers designed in "stilts" of solder-like material that flex so the board can expand without stressing solder joints. This will allow the board to be sold as an OEM product, to be placed in machines that get hotter inside than the TDZ.
The TDZ 310, 410, and 610 workstations are priced starting at $9,995 for a uniprocessor 200-MHz version with RealiZm Z-10 graphics, 32M RAM, and 1G hard drive. They are scheduled to begin shipping in August; first public showing will be at the SIGGRAPH show this August in New Orleans.
Check out their site at http://www.intergraph.com/ics
Shuttle data goes around the world--via the Internet
Austin, TX--Web surfers around the world could recently tap into data from a live space-shuttle experiment, and see the same data being studied by scientists at NASA's Jet Propulsion Laboratory (JPL).
The experiment, aboard this spring's Endeavour shuttle mission, monitored performance of the Brilliant Eyes Ten-Kelvin Sorption Cryocooler Experiment (BETSCE, pronounced "Betsy"). The device was designed to create temperatures as low as 10 Kelvin (-263C or -441.6F) without the vibration of conventional cooling techniques.
BETSCE uses metal-alloy powders that absorb hydrogen refrigerant through a reversible chemical reaction. In the sorption compressor, metal hydride is first heated to pressurize the hydrogen, and then cooled to reduce the pressure. By repeatedly heating and cooling the powder, the hydrogen circulates through the refrigeration cycle. When the pressurized hydrogen is expanded at the cold tip of the refrigerator, the hydrogen turns into solid ice at 10K, according to NASA.
The experiment on board Endeavor measured coolant temperature, pressure, and state; temperature of various system parts; and valve status (open or closed). Data were transmitted from Endeavour to the NASA Johnson Space Center in Houston, which in turn relayed the information to an Apple Macintosh computer running LabVIEW graphical test-and-measurement software at JPL in California. JPL then sent it to National Instruments, maker of LabVIEW, for posting on the company's WWW site.
"There's been great interest in the site," according to Andrew Barton, electronic marketing manager at National Instruments. During one day of the mission, there were 136,000 "hits" (file accesses) at the web site--equivalent to an entire week's worth of visits before the shuttle experiment was posted.
Visitors to the site are seeing more than a spaceboard experiment, Barton says: "They're getting a look at what they will be able to do with their experiments in the future." While LabVIEW has had the capability to use Internet communications protocols for some time, doing so requires fairly substantial network bandwidth and some custom-written software. Sometime this year, however, National Instruments expects to come out with a product to make it easier for any user to post real-time experiment data on the World Wide Web without need for custom programming.
That promises to bring to test and measurement the kind of collaborative tools already available for CAD, letting engineers in different countries share real-time technical data. Or, Barton adds, an engineer running a three-day experiment over the weekend could periodically monitor its status from home, without having to run to the office every day and make sure nothing's gone wrong.
Sandia National Laboratories is already investigating the step after that, he says: not only monitoring the experiment remotely, but making instrument changes from another building--or country.
To view BETSCE shuttle data: http://www.natinst.com/shuttle/ .
Stove-top generator lights Arctic nights
Skerfa, Sweden--A swathe of Northern Sweden is among the most inaccessible regions in the Western World. Children commute to school by helicopter. Farmhouses are best reached by snowmobile or river launch, when the rivers are not frozen over. During the October-through-May winter season, temperatures can drop to -40C. At midwinter, there are only a few hours of daylight. Oh yes, and there is no electric service.
Anders Killander, a doctoral candidate in the Department of Manufacturing Systems at the Royal Institute of Technology in Stockholm, decided to tackle the problem of how to provide electricity for his friends without having to resort to gas or diesel generators. The usual alternatives were not appropriate: long winter nights precluded solar power; the deep freeze closed rivers to hydro-electric power; and his friends' house was in a valley so windmills were not an option.
Killander observed that the house, like most in the region, possessed a cast-iron, wood-fired stove. This time-honored technology, when married with a magneto-thermal effect, was able to generate enough electricity to raise comfort levels. Killander discovered the technique when he ran the problem through the Effects module of Invention Machine Lab, engineering-support software developed by Invention Machine Corp. of Cambridge, MA. The software is an expert system with a vast database of patented scientific principles. Killander queried IM-Effects to find all known ways to generate electricity from thermal energy. Among the responses was the Seebeck effect, published in 1822 by its discoverer, Johann Seebeck.
The Seebeck effect says that when heat is applied to one side of an alloy module and cooling to the other, electricity is produced. Killander reasoned that Seebeck modules equipped with a heat sink and cooling fan would generate electricity when placed on a hot stove, and that a dc/dc converter could turn this electricity to useful purpose.
His design uses a dc/dc converter supplied by Hi-Z Technology Inc. of San Diego, CA. The unit initially powers the fan, whose cooling effect generates more power. Surplus power can be used to charge batteries or power electrical devices directly.
Killander field-tested his two best prototypes at his friends' house in Skerfa last winter. When placed on a stove plate, the better of the two units produced an average of 4 to 7W while the stove was fired. This translated into 50 to 100W-hr per day, significantly less than the 200 to 300W-hr required for the family's "wish list" of six low-wattage lamps and a TV. Nevertheless, the prototype generated electricity from heat that was being produced anyway: essentially yielding free power. Killander, who recently joined Invention Machine as its vice president of European operations, said converters with processor-based controllers would be more sensitive to input fluctuations and therefore have improved output. "Several Scandinavian concerns and even a Japanese one have expressed interest in my design," he says.
Thermo-electric generators are useful in many applications where heat is produced as waste or at low cost. A team at Hi-Z mounted a generator using the company's dc/dc converter on the exhaust manifold of a school bus. The device generated 1 kW and was able to run the vehicle's air-conditioning system on waste-heat only.
--Michael Puttré, Associate Editor
CAD does cables
Amsterdam, The Netherlands--Under pressure to cut project time, Holec Transportation turned to Mentor Graphics' Logical Cable schematic-capture, wiring, and cabling tool to help in the design of its S3/M4 Amsterdam streetcar.
Holec needed a tool that would improve its existing methods of doing system-level interconnects in its train cars but that didn't conflict with those methods. Prior to using Logical Cable, all wiring and cabling data was hand drawn and manually entered into a database. Each time other databases required the information, the data had to be manually compared and transferred.
Logical Cable lets users create and visualize a cabling design, verify its function, and drive downstream processes such as physical cable layout and manufacturing documentation. Mentor Graphics created the tool as an outgrowth of its electronic design automation tools for designing pc boards and ICs.
Holec engineers report that Logical Cable improved efficiency and decreased chance of human error because they only had to input data once into a single-source database and could then output data directly from the cable design.
At the initial implementation, Holec didn't want to eliminate the option of using its existing methods as a fallback. Logical Cable was flexible enough not to require any change in Holec's current methods, company officials say. Due to tight time constrictions, Mentor was able to save the company time by customizing the program on site.
"Mentor Graphics' programmers tried to think our way and even had some better solutions than we had created ourselves," says Holec engineer Anton Steehouwer of the customization effort. "They worked with us instead of for us."
FEA enters the virtual world
Ames, IA--To demonstrate the potential of using virtual reality in design and analysis, researchers at Iowa State University's Iowa Center for Emerging Manufacturing Technology recently incorporated MSC/NASTRAN finite element analysis data into a virtual environment. The goal was to enable engineers to "walk around" an analysis model and inspect the design as it took shape. Funding for the project came from a National Science Foundation grant.
"The ability to see results of stress, fluid, and thermal analysis on a 3-D model significantly enhances an engineer's ability to pinpoint trouble spots and areas of special interest," says Judy Vance, assistant professor of mechanical engineering at Iowa State.
For the project, researchers selected Silicon Graphics workstations and the WorldToolKit from Sense8 Corp. as the virtual-environment software. As they developed and displayed different results, a simple change in code allowed engineers to switch from one type of display to another. Additionally, it made interaction via a 3-D mouse or glove easy, Vance says.
Static analysis. To experiment with a static analysis, engineers used a simple cantilever beam. Their first model consisted of a beam ten inches long, one inch tall, and one-half-inch deep, divided into 12 thin shell elements. They applied a transverse force of 750 pounds to the end of the beam to induce normal bending stresses along its length, then used MSC/NASTRAN to determine stresses and beam deflection. They got normal stress and deflection sensitivities from MSC/NASTRAN and used them in a linear approximation for the solution as they increased and decreased the transverse force.
Engineers also developed a program using WorldToolKit functions to display and interact with the computer model. Picking devices included a 2-D mouse for use with a monitor display and a 3-D mouse for the VR displays.
By using the picking device to "grab" the arrow, the engineer can move it up or down, effectively changing the magnitude of the transverse force, Vance says. "As the engineer moves the arrow the beam deflects and the color contour of the surface changes to indicate the magnitude of the normal stress," she explains.
Vibration analysis. Phase Two of the Iowa State project focused on vibration analysis to find out what happens when certain design parameters, such as spring stiffness in an automobile, change. Engineers displayed the stresses associated with the vibration of the frame at each of its natural frequencies as a color contour over the geometry of the frame. They got the stresses and associated sensitivities from an MSC/NASTRAN analysis.
To facilitate the display of data, Vance says, they added a control handle operated by a mouse. "If the user chooses the button on the handle labeled 'springs,' the stiffness of the four suspension springs will vary as the mouse moves the control handle," she explains.
"Placing engineers in a virtual environment where they can change parameters that affect the outcome of their designs will foster experimentation with novel configurations, multiple design alternatives, and enhance creativity," Vance concludes.
What this means to you
• As OEM competition increases, more companies are thinking globally.
• With the right software, companies can link sites around the world and gain access to the best resources available for their product designs.
• International communication networks can help companies improve product quality and reduce time-to-market.