AT SDRC, NEXPERT OBJECT® TAKES THE MYSTERY OUT OF FINITE ELEMENT ANALYSIS
Structural Dynamics Research Corporation, (Milford, Ohio), a preeminent supplier of FEA software, has come up with a better idea. Using NEXPERT OBJECT│ from Neuron Data, Inc., SDRC has developed the I-DEAS Simulation Advisor'-an FEA front end that guides users through the process of creating, solving and interpreting results from an FEA model. Simulation Advisor uses expert system technology to make suggestions and automatically check each step of the process, insuring that the model conforms to standard FEA practices.
SDRC employs more than 1,100 people in 50 offices in 15 countries throughout North America, Europe and the Far East. Some 60,000 I-DEAS licenses are installed at more than 8,000 customer sites worldwide, including aerospace, automotive and industrial manufacturers. Major customers include ABB, Boeing, GE, Goldstar, Hitachi, Honda, Honeywell, Gilbarco, Land Rover Motors, Lockheed, Lucas Aerospace, Seagate Technology, Siemens, Sony, Thomson Consumer Electronics, and Waterman.
"At its heart, the Advisor is an extremely intelligent user interface that allows an engineer with no training in FEA to conduct a thorough analysis of a prototype design," said Richard Russell, director, analysis products. "The engineer simply specifies what kind of results he's looking for, and the system will lead him through all of the steps needed to accomplish the analysis. The Advisor will ask the appropriate questions and execute the appropriate commands. At any stage of the process the user can view a journal of what rules the system has used, thereby understanding the underlying logic behind a given suggestion."
Rule-based Approach Ideal for Simulation Advisor
The I-DEAS Simulation Advisor is a component of SDRC's I-DEAS Master Series, a set of 70 integrated modules that automate the entire mechanical product development process. SDRC released the Simulation Advisor in March 1993 as part of an ambitious redesign of its entire product line. Using NEXPERT OBJECT and C, the Simulation Advisor was written entirely in a single person-year.
SDRC developed the rules base for NEXPERT OBJECT by drawing upon some 25 years of consulting experience. "The Advisor puts that experience at the disposal of our customers," Russell said. "Some of these techniques could have been automated through algorithms, but most are more complex than that. For example, users must be able to select the appropriate boundary conditions for a model, or simulate a specific operating condition in order to select the appropriate element. These operations cannot be reduced to a formula-but they are ideally suited for a rule-based approach."
In developing the Simulation Advisor, SDRC sought a development environment that was highly portable, reasonably priced, and offered a robust application programmer's interface (API). "The API was very important to us because we wanted to develop not a standalone product, but a highly integrated FEA front end," said Hervé Dannelongue, technical project manager.
"Integration was crucial," said Russell. "A competitor of ours has developed a comparable technology, but it acts more like a textbook that sits passively on the side, rather than playing an active role in the process. In developing the Simulation Advisor, we had to have the rule base linked to our system before we could do anything else because the module is very dependent on the rest of the system. Input from the user is constantly being processed and the Advisor must react to the results."
"We also liked that NEXPERT OBJECT is available on many platforms," Dannelongue said. "Our products run on everything from PCs to UNIX workstations to VAX systems. NEXPERT OBJECT supports the Windows environment on a PC and the Motif graphical user interface under a wide range of UNIX workstations, including Silicon Graphics, Hewlett Packard, IBM, Sony, Sun and DEC."
Guiding the user through FEA
The I-DEAS Simulation Advisor presents users with several levels of interaction, controlled by a single on-screen form. The Advisor begins by presenting users with a menu of goals to determine, for example, whether an automobile suspension will withstand a given set of stresses. After users select the object of the analysis, Simulation Advisor leads them through the steps needed to accomplish the analysis. Along the way, it asks questions, applies its large set of rules, and issues warning messages, if needed. All steps and checks performed by I-DEAS are presented in a scrollable list, each categorized as having passed or failed. Users can obtain additional information on why each step passed or failed.
The Simulation Advisor also provides context-sensitive data on why a step is necessary, as well as providing information to help the user make good decisions during a specific step. Users can request more detailed help, including explanations of the issues to consider in answering a given question.
In the future, SDRC will use NEXPERT OBJECT to build intelligence into other parts of the of the I-DEAS system. "The use of NEXPERT OBJECT pays off by shortening the development cycle," Russell said. "It gives engineers the confidence that the design will work right the first time without having to go through a lengthy build-and-test procedure; and it keeps mechanical engineers closely in the loop. Perhaps most importantly, the analysis gets accomplished much earlier in the process-which will ultimately save thousands of dollars in development costs."
Application: I-DEAS Simulation Advisor: an intelligent user interface that allows an engineer with no training in FEA to conduct a thorough analysis of a prototype design
Environment: NEXPERT OBJECT, Microsoft Windows, Motif under a wide range of UNIX workstations, including Silicon Graphics, Hewlett Packard, IBM, Sony, Sun and DEC.
"The use of NEXPERT OBJECT pays off by shortening the development cycle, giving
engineers the confidence that the design will work right the first time without having
to go through a lengthy build-and-test procedure."
Richard Russell, SDRC director, analysis products