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Analyzing up Front PUBLIC ACCESS

The Power to Test as they Design Promises to Take a Bite Out of Time to Market, Some Engineers Say.

[+] Author Notes

Associate Editor

Mechanical Engineering 122(10), 88-91 (Oct 01, 2000) (4 pages) doi:10.1115/1.2000-OCT-6

This article highlights that up-front computer-aided engineering (CAE) dramatically decreases product lead time. Up-front CAE entails vesting responsibility for performing finite element analysis tests and other analysis tests with the design engineers. The designers use specific software packages to analyze their first-stage designs. This way, they can easily change designs that do not pass analysis tests-such as vibration or stress tests-before passing them on to an analyst for in-depth study. Not every engineering company, however, is turning to up-front CAE even as it faces the need to get products to market faster. Some engineers, like Zlatko Penzar, find that their present analysis hierarchy works just fine. He is a senior engineer for the fuel systems division of Mannesmann in Dusseldorf, Germany, another auto components supplier. Engineering departments have to find their own answer to the relationship between designer and analyst. The important thing is that once an answer is agreed upon, it happens the same way every day. A working atmosphere that functions reliably and smoothly is really the key to successful product design.

The engineering departments of many large companies are turning to what's called up-front computer-aided engineering as a way to improve productivity and slash the time it takes to get their products to market. But the move to up-front CAE, also referred to as first-pass analysis, usually means a full- scale turnabout in the way engineering departments operate. Those kinds of cultural changes often can't be carried out without certain upheaval, according to some engineering leaders who speak from experience. They're in the front ranks of departmental restructuring.

"Up-front CAE dramatically decreases product lead time," said Scott Baxter, manager of the hardware analysis and simulation group at Delphi Automotive Systems in Kokomo, Ind. "With these expert systems, something that used to take us weeks to design with building and testing now takes us one day."

Baxter's group at Delphi makes automotive electronics systems and components-everything from small electronic units that determine when to deploy an air bag to CD changers and speakers. The multimedia sector is the quickest growing part of Delphi's business because auto entertainment centers are more popular and affordable than ever, Baxter said. But other changes in the auto industry dictate the need for first-tier design engineers to take on a great deal of responsibility for the design analysis, he added. Customers are seeking smaller components and the automotive industry needs these new components faster than it did in the past.

"Implementing up-front CAE is critical for us because the physical size of our components is shrinking so dramatically," Baxter said. "And they had been mounted in the passenger compartment, where temperatures were 85°C, but now they're in with the engine, which is at about 125°C, and the vibration profile goes up dramatically and more soil comes from the engine."

All those changes add up to a need for more and more analysis simulations-as well as different types of virtual tests-to be carried out on the parts to make sure they meet stringent production requirements. Under the former Delphi engineering process, continual checking of part designs to see if they were viable for production took too much time and work by analysts to be economically sound, Baxter said.

Up-front CAE entails vesting responsibility for performing finite element analysis tests and other analysis tests with the design engineers. The designers use specific software packages to analyze their first-stage designs. That way, they can easily change designs that don't pass analysis tests-such as vibration or stress tests-before passing them on to an analyst for in-depth study.

The analyst may run further computer simulations on a model or may build a prototype for testing. A number of new software packages applicable for the product design engineer, who may not have much analysis training, makes up-front CAE possible, according to Baxter. And the advent of more and more advanced analysis software means that the advanced analysts can often run virtual prototypes. They no longer have to spend as much time and money building real prototypes, though some are still necessary.

Before Baxter's company began the phased-in move toward up-front CAE, product engineers passed their first designs off to analysts who ran simulations and reported results to designers. The original designers then began a round of redesign, passed it back, and the process repeated itself. But this method of product creation meant that the analysts were encumbered with testing preliminary designs that had never undergone analysis and needed a lot of work. The analysts also found themselves doing fairly rudimentary chores.

The process of giving early analysis responsibilities to product engineers rather than analysts began three years ago at Delphi and is still unfinished, Baxter said. The move to up-front CAE involves creating what Baxter termed three engineering levels.

Level one engineers are the product designers who now have the responsibility of analyzing-or virtual testing through computer simulations-their designs to see if they meet requirements for manufacturability. Level two engineers serve as a conduit between the product design group and the 10 technical design experts on board at Delphi. The second-level analysts answer questions from product designers about what types of analysis they might need to run or what particular tools they need to use for certain simulations, Baxter said.

Level three engineers are 10 technical experts, one of whom is Baxter. These people establish design guidelines and solve difficult analysis problems. Because these 10 engineers serve all Delphi engineers, the level two engineers answer more basic questions and the expert level engineers tackle stickier analysis problems.

"If you had to exchange preliminary designs between the engineers and my group-the expert group-it would take much longer, and we're resource constrained," Baxter said. "We probably couldn't run as many design iterations as product engineers can at their desks."

Of course, all these changes mean a switch in the kind of computer tools that are used for simulation and analysis, he added. The most significant has been the move to train all product engineers on DesignSpace, analysis software applicable for first-time users. The software is from ANSYS in Canonsburg, Pa. These engineers use Unigraphics design software from Unigraphics Solutions of St. Louis for three-dimensional modeling and the DesignSpace software for testing.

The level two engineers use more complex FEA and analytical tools, including ANSYS analysis software and home-grown Java-based applications, as do the level three engineers, Baxter said.

"Before, you'd need a Ph.D. to do analysis ," Baxter said. "Fifteen years ago, this kind of analysis was on the Ph.D. level; 10 years ago, it was down to master's and now kids in college are getting some training in this."

Engineers using DesignSpace software analyze as they design, then make needed changes. Here, a designer studies a Nascar lower control arm with the software.

Grahic Jump LocationEngineers using DesignSpace software analyze as they design, then make needed changes. Here, a designer studies a Nascar lower control arm with the software.

The creation of new computer tools, such as Design Space and other software equivalents allows entry-level engineers who may have run only a few design analyses in college or graduate school to easily learn basic analysis. That frees up the highly trained analysts for advanced work, he said.

"The Ph.D.s are now free to work on developing new tools and to learn those tools," he said.

Baxter himself, for example, now creates more computerized analysis models to run tricky analysis problems that are specific to Delphi. Before implementation of up-front CAE, he created computer models for much more common problems. Now the common problems are solved with tools included in the DesignSpace software, Baxter said.

"Instead of software tools being used once or twice by the experts, they're now used hundreds of thousands of times by the level-one engineer," he said.

Delphi's phase-in plan calls for all level-one engineers to be trained in the analysis software by next year. They will have to run analyses as they design until they can prove, through analysis, that their designs meet manufacturing guidelines. By 2003, level-one and level-two engineers should both share advanced-analysis know-how, with level-two engineers getting even more advanced analysis skills than they presently receive, Baxter said.

The move toward combined design and analysis-rather than involving an expert analyst for each design iteration- has meant a significant change in responsibilities for level-one engineers. That's why the move toward up-front CAE is being phased in slowly at Delphi, Baxter said. The design engineers need to get acclimated to the new role.

Two major auto component suppliers plan to restructure their engineering departments to pass more design analysis responsibility to designers.

The additional job responsibilities also mean that product designers need new job definitions that include analysis, and supervisors have to make sure designers have enough tlme in the working day to exercise analysis skills.

"We've determined that engineers spend 25 percent of their time actually doing engineering. The rest of the time is spent chasing suppliers or finding bills of materials or just filling out paperwork," Baxter said. "We're trying to change that number so they spend 50 percent of their time doing engineering." Delphi hired engineering assistants to help with paperwork. "We want the mechanical engineers' primary job to be designing and verifying designs;' Baxter said.

These days, as the marketplace calls for increasingly tighter compression of the design cycle, up-front CAB will soon become commonplace, said Greg Roth, a senior specialist at Eaton Corp. in Cleveland. His company makes electrical power distribution and control equipment, engine components, and hydraulic products for the aerospace, automotive, and marine industries. Roth works in the research and development plant in Southfield, Mich., focusing on fluid power and hydraulic systems for trucks.

His company is piloting an up-front CAE program. The need for product engineers to analyze is in keeping with industry trends, Roth said.

"The trend is to get the product released faster," he said. "The customer needs changed products faster as the world speeds up. The bottom line is a compressed product-release time for devices in the automotive market. The product-release time has gone from 48 months to 24 months."

Manufacturing first stepped up to help shave that time through practices like just-in-time manufacturing and inventorying to ensure that goods didn't sit in warehouses. But now it's up to the engineers to help speed the product-release cycle, Roth added.

Of course, up-front CAE, like JIT manufacturing, is the solution of choice when it comes to cutting the time spent on product design because it's a way to shave development time.

"It's a way for us to do our homework, to work out our design issues up front, so you have a lot more settled product after the development stage," Roth said. "We don't want to do analysis on a full-blown CAD model. We want to do analysis at the same time as the model matures."

Although more companies are turning to CAB, giving analysis packages to product designers can be a difficult design methodology to implement because results aren't seen immediately and because the new way of designing is such a vast change from the methods already in use at most engineering firms, Roth said.

At Eaton, the up-front CAE pilot takes a slightly different form than Delphi's phase-in plan. One group of Eaton product -designers is now testing their designs, also on DesignSpace software, as they design. Only after initial designers have worked out many of the kinks in their products do they pass them on to analysts for further testing.

"But a designer can do four design iterations a day, versus the middle CAE analyst doing only one a day and the top-level analysts taking four days," Roth said. "That 's because a designer knows the product and knows how to fix it, whereas the analysts have to familiarize themselves with the whole design."

The Eaton product engineers who aren't in the up-front CAE pilot group continue to do things the traditional way. That is, they complete a design, then pass it to an analyst who finds potential problems and, possibly, even builds and tests a prototype of the design. The analyst returns the tested design to the product engineer with needed changes noted. At Eaton, design engineers use solid modeling software from PTC of Waltham, Mass.

With expert systems, something that took weeks to design, build, and test now takes one day.

Roth has found that the traditional Eaton method of designing a product and then passing it to an analyst often doesn't work smoothly, because the group that carries out simulation testing is overrun with work.

"When you have a core CAE group that does all the CAE on products, there's usually a bottleneck on that level and product designers might try to go around the CAE level and just leave CAE undone," Roth said. "Or, in another instance, they might go around the analysts because they fear the outcome of CAE on their design.

"Nobody wants to be told that their baby is ugly," Roth added.

Having the product designers take more responsibility for analysis frees up higher-end analysts to do more indepth analyses, he said.

Managers at some companies don't bite on implementing up-front CAE because they notice right away that when it's in place, it takes product designers much longer to get out their initial designs, Roth said. That makes it look like the company is paying more than previously to get the product out of the first stages of design. However, once managers see that products leaving the first stage are much closer to manufacturability than before, they're more willing to support up-front CAE, he added.

Another barrier to implementing the switch is that product designers sometimes have a hard time adju sting to their new job requirements. Even as they design and analyze, they realize the product design will still eventually need to be passed to a CAE expert, who can find fault, which takes some of the wind out of their sails as they complete their up-front CAE requirements. Designs passed to experts may still come back with changes needed, because the engineers use the easy-to-use analysis software and don't carry out in-depth testing methods.

" I think of the software our product designers use as kind of a calculator," he said. "We all use the sine function on a calculator, but we may not know the process behind what goes on when we press the button. But when you get higher up in the company, you'd better understand the process that goes on when you're pressing the button."

Not every engineering company, however, is turning to up-front CAE even as it faces the need to get products to market faster. Some engineers, like Zlatko Penzar, find that their present analysis hierarchy works just fine. He is a senior engineer for the fuel systems division of Mannesmann in Dusseldorf, Germany, another auto components supplier. His company has never set in stone a specific product designer-analyst relationship. Instead, over time a casual relationship evolved that continues to work for the company.

Penzar's division does not house a centralized CAE department. Instead, one CAE analyst works with each product development team to see the product through the entire development process. An analyst always gives input during the first discussions of a new product idea. After that, product engineers keep up with the analysts via telephone, e-mail, and work-group meetings, Penzar said.

"The advantage is that the analyst lives with the product from conceptualization through feasibility studies, to fixing the final design," he said. "The disadvantage is that when the analyst runs into a specific problem, he has to get advice from his colleagues, who haven't been following the design."

At Mannesmann, analysts use various higher-end ANSYS analytical software to run their virtual simulations. Two analysts serve 100 engineers, although a few other analysts often pitch in, Penzar added.

"It doesn't sound like a lot, but this is working. And it's been working:' he said. The reason it works, he added, is because high-level CAE is often invaluable in the concept phase. It lets engineers immediately see that one design would work better than another one, without spending the time it takes to build, then test, a prototype.

At many companies, up-front CAE promises to get products to market faster, thereby capitalizing on the lucrative contracts that follow when suppliers promise a quicker time to market than competitors. But other companies find that their traditional methods work the best.

As Penzar said, engineering departments have to find their own answer to the relationship between designer and analyst. The important thing, he said, is that once an answer is agreed upon, it happens the same way every day. A working atmosphere that functions reliably and smoothly is really the key to successful product design, he said.

Copyright © 2000 by ASME
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