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In-School Analysis PUBLIC ACCESS

Introducing Undergrads to CFD and FEA Software isn't a Straightforward Affair.

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Mechanical Engineering 130(01), 32-35 (Jan 01, 2008) (4 pages) doi:10.1115/1.2008-JAN-3

This article highlights introducing undergrads to computerized fluid dynamics (CFD) and FEA software that is not a straightforward affair. Computerized fluid dynamics has become mainstream more recently, but many engineers are finding it just as important to their daily work. In order to prepare engineers to enter such a world, professors have begun a conversation to determine the best way and the best time to introduce students to the analysis software they will likely need on the job. The subject is more challenging, both to learn and to introduce into the curriculum, than computer-aided design. Instructors agree that their students first need a good grounding in CAD before moving on to analysis. Introduction to the software comes after instructors are sure students are comfortable with CAD and have become familiar with a range of analysis concepts. Teaching CAD is a lot easier than teaching CAE, so schools are finding they cannot substitute their CAD teaching methods when it comes to CFD and FEA.

Mechanical engineering students have a lot to learn and only a few short years to do it. First, they'll need to be versed in engineering concepts and the mathematics behind them. Then, they'll have to learn a slew of mathematical formulas and to become proficient in computer-aided design software.

With this pressing schedule, it's easy to see why engineering schools are scrambling to define the role that analysis software should play in their undergraduate programs. The software is relatively new to nonspecialists, and many mechanical engineers now use analysis software on the job.

Professors want their students to get up to speed on the technology, but they question at what stage they should introduce the software, according to Milos Coric, manager of the manufacturing and process laboratories at Northwestern University in Evanston, Ill.

Instructors are also questioning how to ensure that students understand what they are asking of the software, Coric said. They also wonder how to fit the subj ect of computer-assisted engineering into an already-packed undergraduate schedule. And which package should they use for instruction, anyway?

After all, analysis software made the everyday engineering scene only fairly recently. From its inception in the 1940s until about a decade and a half ago, finite element analysis had been performed exclusively by specialized analysts who held Ph.D.s in the subject and had devoted their careers to the discipline. But the FEA field has seen great change over the past 15 years, with a jump in the number of computer technologies available to an increasing number of engineers.

Computerized fluid dynamics has become mainstream. more recently, but many engineers are finding it just as important to their daily work.

In order to prepare engineers to enter such a world, professors have begun a conversation to determine the best way and the best time to introduce students to the analysis software they'll likely need on the job. The subject is more challenging, both to learn and to introduce into the curriculum, than computer-aided design.

"CAD and CAE complement each other and are critical for building and testing products virtually, but this stuff is changing all the time," said Krishnan Suresh, an assistant professor of mechanical engineering at the University of Wisconsin in Madison. "So how do you address this adequately in the college setting where students not only need to learn what it is, but how to do it? And what package do you use?"

Universities also question the breadth and depth with which they should introduce students to CFD and FEA practice. Many of these students, after all, will not go on to study fluid flow and FEA at a graduate level. And they'll likely receive on-the-job training in the applications they'll use at work, although they'll certainly need to understand analysis concepts, said Dave Anderson, a professor of mechanical engineering and computer sciences at Purdue University in West Lafayette, Ind.

Instructors agree that their students fi rs t need a good grounding in CAD before moving on to analysis. Coric said that, at N orthwestern, introduction to the software comes after instructors are sure students are comfortable with CAD and have become fa miliar with a range of analysis concepts.

According to Suresh, teaching CAD is a lot easier than teaching CAE, so schools are finding they can't substitute th eir CAD teaching metho ds when it comes to CFD and FEA.

"CAD foc uses on geometry and most of us have a natural ability to visualize geometr y," Suresh said . "I know what you mean by a cube or a sphere. I can visualize what you're talking about. Also, CAD relies on concepts like geometry confirmation and intersections. T hey're not trivial, but they're easier to understand beca use I can draw on a board to say, 'Here 's what I mean by intersection.'

"But CAE rela tes to complex physical phen omena like fluids and things brea king and co rroding," h e added. "Th ey're more difficult to teach and students can't visualize much of this easily."

Analysis concepts can be tricky to wrestle with and the introdu ction of software into the mix can become a bit of a chicken-and-egg scenario, Anderson said. It can be diffi cult for students to visualize the analysis problem. they're asking the software to solve. CAE can help them visualize such problems, but without proper background in analysis concepts they won't understand what they're looking at.

According to Suresh, "These are the diffi culties you face in teaching CAE. We want to teach CAE at a level that's ready for industry, but our main challenge is time.

Every department in the co untry is faci ng a challenge because we don't have space in our curriculum. Students are increasingly pressured by parents and funding issues to get out in four years and be ready for industry."

Each school finds its own way to introduce concepts like fluid flow and FEA, and then the software behind it. Purdue University, for example, now offers senior-year elective classes that focus on compute r-aided engineering, but every undergrad will receive CAE training, Anderson said.

"I don't believe I know the answer to, 'How do you teach CAE?'" he said . "It's still a learning process for all of us, but b ased on my experience you introduce the basics of heat transfer or fluid flow at a point in the curriculum. Then, you introduce CAE methods directly into those courses. Students can solve simp le textbook problems using Ansys or Nastran."

Northwestern recently incorp orated Fluent CFD software from Ansys Inc. of Canonsburg, Pa., into its class rooms. The software is part of the Partners for the Advancement of Collaborative Engineering, or PACE, program, which sells discounted software to universities. It's a joint venture of General Motors, Sun Microsystems, and Siemens PLM Software, and their partners and supporters, such as Ansys.

According to Coric, "Basically, before Fluent ours was a theoretical approach, with not much CFD software at all."

Getting a proper grounding in the principles of fluid flow and the like before fi ring up a software program helps students better understand the basics of engineering, Suresh said. Half the battle is ensuring that students can accurately frame and input the problems they want CFD and FEA to analyze, he added.

Identifying the problem in a simple manner is one of the most important lessons CAB teaches, Suresh said. "Despite advances in software programs, many complex problems can't be solved with them," he said. "Students need to be trained to say, 'How do I simplify the problem?' That's the core of engineering.

"There's no way to capture the detail of a full engineering automotive model, after all, so students need to learn to ask themselves: 'Is the problem linear? Nonlinear? What forces need to be analyzed?' " Suresh added. "Students soon realize CAE is about asking the right questions. That's why we need to teach CAE. That's the core of engineering, and software can help teach it.

"CAE is not about clicking a few buttons and so lving a problem. It's about giving them an auto structure chassis and saying, 'Give me what the vibration of the chassis is,' "he said." If they can do it, they know CAE. If not, they've learned to move some buttons around."

Today's engineering students need to know how to use analysis software. But when and how do professors introduce them to it? That is the question.

Grahic Jump LocationToday's engineering students need to know how to use analysis software. But when and how do professors introduce them to it? That is the question.

PROFESSORS WANT TO TEACH CAE SO STUDENT ARE READY FOR INDUSTRY AT GRADUATION. BUT THEIR MAIN CHALLENGE IS FINDING SPACE IN THE CURRICULUM THAT ALREADY PACKS SO MUCH INTO FOUR YEARS.

Northwestern Univer sity recently introduced Fluent CFO software from Ansys Inc. into its classrooms. The company is a participant in Partners for the Advancement of Collaborative Engineering.

Grahic Jump LocationNorthwestern Univer sity recently introduced Fluent CFO software from Ansys Inc. into its classrooms. The company is a participant in Partners for the Advancement of Collaborative Engineering.

The professors interviewed for this article all agreed upon the need for students to crosscheck the results that their software programs return. Software may seem miraculous at first blush, but is, after all, only as good as its programming and as the engineering information supplied.

Fledgling engineers must learn FEA and CFD concepts before they can understand the results the software returns, Suresh said. They can't just rely on software as a tool to spit out the answer. In fact, students need to know that the software can make mistakes. And they have to be primed to find those mistakes.

"Students really need to be trained to ask, 'How canT be sure the colorful plots reflect reality?'" he said.

Anderson at Purdue emphasizes to hi s students that analysis is more than a colorful picture. Nor can they operate a program by simply plugging in numbers, waiting a bit, then getting correct results.

"We try to connect software to theory, to ask them to do a sanity check on the numbers. Don't trust the numbers," he said. His students analyze two-dimensional projects they've designed in Pro/Engineer, using both Pro/Mechanica fiom PTC of Needham, Mass., and Ansys. Students use 2-D to see results more readily without getting bogged down in pictorial simulations, Anderson said. The Purdue program also deliberately mixes Ansys and Pro/Mechanica to expose students to different analysis programs.

Educators said that, to double- and triple-check the results that software returns, students will have to repeat analyses again and again. They should solve the problems in more detail to see if the results remain stable. If results fluctuate, the results are suspect.

Results must stay the same as students solve with finer and finer detail, Suresh said . Students can also crosscheck the software's solution by making a change to the model to see if results change as expected.

That point cuts to the crux of the problem, as Coric sees it: How do professo rs best g ive students a CAE problem they can solve? Textbook problems are very easy to solve, but don't have the challenges of the real world.

Coric often has students use Fluent to verity problems they've solved by hand.

Suresh warns that the transition from simple textbook problems to real-world problems won't be easy for students. After all, engineers use CAE on the job to solve complex problems.

To help students take small steps into real-life applications while still in college, Northwestern en courages them to compete in design-build competitions like the North American Solar Challenge and the Formula Sun Grand Prix.

"To be competitive, all these teams have started using software to analyze suspension and kinematics and airflow around their vehicles," Coric said. "They're running a whole project from scratch, from design to analysis, to hopefully race and hopefully win."

FLEDGLING ENGINEERS NEED TO LEARN FEA AND CFD CONCEPTS BEFORE THEY CAN UNDERSTAND THE RESULTS THE SOFTWARE RETURNS. IN FACT. STUDENTS NEED TO KNOW THAT THE SOFTWARE CAN MAKE MISTAKES.

Along with figuring out how to introduce CAE and when to introduce it during the undergraduate years, schools consider what package to use. Each one will likely choose something that meets the needs of industries that frequently recruit its graduates, and that meshes with teaching style and method.

The CAE package a school eventually goes with should be well integrated with its primary CAD system, Suresh said. Not only does it make quick analysis easier, because a student can click over to the analysis program directly from the CAD application, but it saves faculty members from teaching two separate software environments, he said. He added that CAE packages that include well-integrated pre- and post-processors save schools the need to buy those applications separately.

The application should also b e able to handle realworld geometry.

"I want students to solve real-world problems," Suresh said. "Many CAD systems are limited to simple 2-D. That is a stumbling block." He wants to see students informed about 2-D and 3-D analyses.

Schools must consider the packages most often used by the companies for which th eir students will likely work. But instructors shouldn't be unduly swayed by that consideration, he said.

"Each industry has its own favorites, but you're training them more like a technician when you just train them on one particular software," Suresh said.

As with many things in this age of advanced engineering technology, undergraduate institutions are finding their way toward using CFD and FEA software in the classroom. The learning process continues for everyone.

RACES IN THE SUN

Northwestern University is one of more than two dozen university teams participating in the current North American Solar Challenge, a cross-country road race that will take solar-powered cars from Dallas to Calgary this July.

Each team will race a solar powered vehicle, which it has designed and built from the ground up. As Milos Coric, manager of the manufacturing and process laboratories at Northwestern University, pointed out, students get to practice a range of highly analytical engineering skills in order to win a race with a car powered solely by sunlight.

According to Don Eberle, the director of the North American Solar Challenge, the competition is somewhat behind its normal schedule because of changes that involve both funding and organization.

The Solar Challenge is normally held every other year and was last run in 2005. A qualifying race, the Formula Sun Grand Prix, is usually run in off years. Both had been overseen by the Formula Sun Educational Foundation. That organization is now on hiatus, and Crowder College of Neosho, Mo., has taken over its role. The foundation eventually will be reestablished, Eberle said .

The major source of funds for both events had come from the U.S. Department of Energy. Toyota has stepped in to replace DOE as the chief sponsor.

The next Formula Sun Grand Prix will be held sometime this spring, Eberle said. The Grand Prix is a three-day event on a closed-road track. Teams have to take part for at least one of the days to qualify for the cross country competition. To qualify for the North American Solar Challenge, a team 's solar-powered car must travel a minimum of 200 miles in eight hours, Eberle said.

Information about the race is available on the American Solar Challenge Web site at http://americansolarchallenge.org.

Copyright © 2008 by ASME
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