Design News for Design and mechanical engineers 22208

March 2, 1998 Design News

GUEST COMMENTARY Exclusive interviews with technology leaders

Next CAE breakthrough: more engineering on CAD solid models

Michael Bussler, President Algor Inc., Pittsburgh, PA

Engineering is about thinking and about making parts, says Bussler. CAD is for making parts more efficiently.

Design News: Some software companies say they are bringing FEA to design engineers. Who did FEA before?

Bussler: Design engineers. Ten years ago in one of our training classes, I asked for a show of hands of who was a stress analyst. One person raised his hand. Nineteen others said they were design engineers. Design engineers are qualified to do analysis. Though large companies have had stress analysts, smaller firms have always had design engineers doing analysis.

Q: How are CAD and engineering related?

A: They are related in that both are necessary to make products. Engineering has to do with proper part functioning. CAD has to do with manufacturing. CAD lets you make something. CAD has brought productivity gains and lowered the cost of making products. Companies are putting old drawings into CAD and getting more efficient manufacturing. But, it's the same design. CAD lets you quickly and inexpensively make changes. Engineering affects the functionality of a product. It's not about drawing pictures or about manufacturing. Understandably, manufacturing companies spend relatively little on engineering compared to what they spend on CAD. For every dollar they spend on CAD, I estimate they spend about five cents or less on engineering. Their business is manufacturing products, so that's reasonable. The balance doesn't swing to engineering until you get into military applications. Our business is to sell to engineers.

Q: Does engineering come before CAD?

A: It depends on what engineering you will do. In a new design, you do lots of engineering work before CAD. You think mostly, trying to understand the size, weight, and performance characteristics. CAD, then, is a production-drawing tool. You do a lot of analysis on engineering models that simulate functionality of the part rather than the models for making it. After you go through the CAD process, you do more analysis. Most of the time in a civilian economy, companies are not making new parts. Their primary concern is to get more production at a lower cost.

Q: What's the next breakthrough in finite element analysis?

A: The ability to do more engineering with the CAD solid model. Engineers will be able to do more than just linear static stress analysis. The real world is dynamic, not static. We will introduce an extension of our Accupak/VE to do mechanical event simulation or virtual prototyping on large-scale CAD solid model assemblies. This is the culmination of five years of research and development at Algor and Carnegie Mellon University. We are able to combine motion capabilities of kinematics and analyze using large-scale finite element analysis models from CAD solid models. With mechanical event simulation, you don't have to put the force in. The engineer will take a little more time setting up the engineering model, possibly a good deal more time in computing, but much less time figuring out the force.

Q: Algor commercialized brick-element technology in FEA. What is its status?

A: We brought it to the point of high usability. You can get bricks as easy as tetrahedral elements in FEA models now. So, users have a choice. We believe that bricks give better answers for less computing resources. Now, we are moving into mechanical event simulation to change the ways engineers work. That makes engineering more conceptual. It eliminates a lot of the work engineers used to do to support linear statics, where they had to guess at loads. With mechanical event simulation, it doesn't matter. You see how it will move. Forces are internal. What's important is the experience of the part and where the force comes from, such as an impact or other changes in motion. With our software, the engineer can model the cause of the forces in the mechanical event.

Q: What's the biggest contribution of finite element analysis?

A: Analysis is important for finding out why something might break and how to prevent that. There's less engineering of new products today. In the modern economy, with neither the space race nor the cold war, FEA's greatest importance is its ability to enable engineers to refine existing products and reduce costs.