In the ongoing drama of computer-aided engineering, technology is progressing from mere automation of individual design tasks to broader capabilities that not only change the design process but also offer strategic competitive results. A dramatic new example is Altair Computing Inc.'s OptiStruct, a powerful, finite-element-based optimization tool for the conceptual design stage. Unlike traditional structure-optimization software, OptiStruct does not require an initial design as input. So, instead of designing first and then optimizing, users can reverse the process by using the software to generate a conceptual design of the stiffest structure possible from minimal information. All that's needed are the maximum area or volume, the specific mass of material, and the load cases and boundary conditions. OptiStruct doesn't replace traditional optimizers -- they will still be used downstream in the design process. "OptiStruct's significance is in its ability to facilitate the conceptual-design process by giving the engineer the best possible starting point," explains James Scapa, president and CEO of the Troy, Mich., company. Occupying a new niche in the growing roster of concurrent engineering tools, OptiStruct offers the designer help in selecting the best starting point, one that could easily be missed in conventional procedures. "In the traditional process, the layout or topology of a part is fixed by the engineer, as are potential paths of change, even though a better design might exist with an entirely different layout," says Mr. Scapa. That happens because the engineer is depending on "gut" feel or is proceeding with ideas inspired by an existing part. In contrast, OptiStruct generates an optimal layout analytically, prior to the first design iteration. It offers the best possible starting point for designing the structure. The strategic payoff is in the potential of the software to greatly enhance a company's concurrent-engineering performance -- reducing product-development time, paring time-to-market, and making possible a higher-quality product at lower cost. OptiStruct strengthens the conceptual-design phase of product development -- where 85% of the total time and cost of product development is committed, but only 5% of the time and cost of a project has been expended. With OptiStruct, the conceptual designer can quickly establish the best departure point for a new structure. Technology investments made at this point provide rapid paybacks in prototype development. Starting with an optimum structure eliminates the traditional build-and-test merry-go-round. Altair says the software is broadly applicable to the early conceptual-design step in any industry -- wherever structural performance is an issue. The early adopters are the automakers, but new users are beginning to put it to work in aerospace, biomechanical, and civil-engineering tasks. Improving the shapes of bone implants is an intriguing possibility for OptiStruct. As more becomes known about how bone structures grow over implants, Altair's software might be used to generate implant shapes that would encourage optimal bone structures. Mr. Scapa says the software's most valuable characteristics are its ability to:
- Generate optimal design configuration with minimum input.
- Save design time and reduce design iterations.
- Provide a powerful methodology to reduce structural mass.
- Combine multiple-load cases to form robust design.
- Be used to evaluate and improve an existing design.
In traditional size/shape optimization, the person performing the analysis applies finite-element software to an existing shape. Typically the software divides a computer model of a part into elements that simplify the mathematical process of analysis. With OptiStruct, the three-dimensional space the intended part is to occupy is divided into elements. The software begins with the assumption that the design space is porous media consisting of an infinite number of small voids. In the optimizing process, the software redistributes material by changing the size and shape of the voids -- modifying how the density is distributed to conform with the specified mass of material, the load cases, and the boundary conditions. When examining an existing structure, OptiStruct leaves gaps in the structure to indicate what frame members might be ineffective or redundant. The software runs on low-end UNIX workstations and platforms up to and including Cray supercomputers. As spectacular as this software might be, Altair doesn't position OptiStruct as a way to replace engineers. For example, while the software does facilitate discovering the best shape for a part, OptiStruct stops at that point. In addition to finishing the design process, engineers must still define the manufacturing process, the assembly process, and the finishing steps. Nor does it replace existing optimizers that would be normally used after the design is finalized. Altair says engineers would still use them to fine-tune the structure. The ideas behind OptiStruct had their beginnings with Martin Bendsoe, a mathematics professor in Denmark, Alejandro Diaz, a professor of mechanical engineering at Michigan State University, and Noboru Kikuchi, a mechanical engineering professor at the University of Michigan. Conversion of those ideas into the product called OptiStruct began with Jeffrey Brennan while he studied under Prof. Kikuchi. Mr. Brennan carried his enthusiasm for Prof. Kikuchi's ideas to Altair where the commercial product called OptiStruct took form. He is now product manager for OptiStruct. Altair Engineering Inc. was founded in 1985 as a result of a chance meeting of three engineering consultants during a project at a General Motors Corp. facility. The three, Mr. Scapa, George Christ, and Mark Kistner, became the founders of Altair Engineering Inc., now a global automotive-engineering consulting company. Three years later Altair Computing Inc. was established as a sister company to market advanced engineering software solutions. Today, Mr. Scapa serves as president and CEO of both organizations. Initially, Altair Computing's mission was to function as a distributor of advanced software products such as Parametric Technology Corp.'s Pro/ENGINEER and PROBE, a p-solver now owned by MacNeal Schwendler. "We initially began to distribute the Pro/ENGINEER CAD/CAM package because we knew it was going to be a winner in the marketplace," says Mr. Christ, who now serves as director of software development. "Even though it was a winner, it was the biggest mistake we ever made. We knew it was the right product, but we executed the wrong action. Instead of distributing it, we should have merely bought a lot of PTC stock!" He says Pro/ENGINEER in the early days was really more of a design tool than an engineering tool, and unfortunately all of Altair's contacts were in engineering. Even though Altair Computing is no longer distributing Pro/ENGINEER, Altair Engineering Inc., continues to use it extensively. The business focus of Altair Computing then shifted to engineering software products that had been developed internally. "Like OptiStruct, the latest product, these represent innovations in engineering software that were first developed to solve engineering problems for the clients of Altair Engineering," says Mr. Scapa. He believes the synergy between the two organizations is an important asset. "Before Altair Computing brings engineering software to market, it passes real-life tests as an engineering solution for the clients of our consulting organization." In addition to OptiStruct, Altair Computing's product line includes Hypermesh, MotionView, MotionPlot, and SuspensionGen. Hypermesh, introduced in 1990, is the company's mainstay. It is a pre- and post- processor for finite-element-analysis programs such as MacNeal Schwendler's NASTRAN. "Its advantage is speed -- up to 25 times that of older codes," says Mr. Christ. "Hypermesh does everything short of finite-element analysis. It creates the input for the analysis and then it takes the output from the analysis and helps you interpret it. That really got us going in the commercial software distribution business." Altair Computing isn't entirely out of the distribution business. This year it agreed to market GENESIS, an optimization package with an integrated finite-element solver. Developed by Vanderplaats, Miura & Associates, Colorado Springs, Colo., GENESIS has a conceptual fit with OptiStruct. While OptiStruct would be used to establish the optimum starting point, GENESIS would perform the final optimization.
