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analyzing up front

The power to test as they design promises to take a bite out of time to market, some engineers say.
By Jean Thilmany, Associate Editor
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 dra-matically 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.

Three Engineering Levels

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.

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

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."

The creation of new computer tools, such as DesignSpace 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.

Role Readjustment

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.

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 time 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.