Nonlinear Analysis in MSC Nastran to Reduce Design Bottlenecks

Nonlinear Analysis in MSC Nastran to Reduce Design Bottlenecks

Sporadic use of advanced finite element analysis (FEA) software, such as nonlinear analysis by design engineers, can result in either excessive refresher training time or a bottleneck while in the queue for an analyst. The cause is a result of different types of solvers requiring different models. Commercially available translators can help, but still require significant amounts of cleanup. However, by integrating solvers in MSC Nastran’s SOL 600, the same model in the familiar MSC Nastran format can be used for both liner and MSC Marc nonlinear analysis.

“We use nonlinear simulation primarily for contact analysis,” says Dr. Michael R. Urban of Sikorsky Aircraft’s Structures Research department. “In the past, when engineers had a contact problem and needed a better understanding of the issues involved, they created a second model in MSC Marc Mentat for analysis in Marc or another nonlinear program. If the engineers had not been trained to use nonlinear analysis programs, they sent the model to an analyst, thus creating a bottleneck in the design process.” Previously, MSC Nastran users who wanted to perform analyses studying complex materials, small deformations, large strain, and 3D surface-to-surface contact had to learn how to use MSC Marc and its Mentat interface because Marc nonlinear analysis had been developed to solve models created with the Mentat pre-processor and view the results in the Mentat post-processor. Therefore, intermittent users of Marc had to either review the nonlinear training material whenever they needed to run a nonlinear analysis, or send the problem to an analyst to be run and wait for the results to be returned.


With MSC Nastran, specific translators were developed between MSC Nastran and Marc, called “Solution 600.” Transparent to the user, the Marc solver does the number crunching for advanced nonlinear analysis using existing MSC Nastran models and providing results in the familiar MSC Nastran format. SOL 600 actually consists of two translators. One of them translates MSC Nastran input data for Marc to analyze. The second translator converts Marc results into MSC Nastran formats for post-processing. For the user, SOL 600 significantly expands nonlinear capabilities within Nastran and opens up new application arenas.

Most engineers at Sikorsky do not work with contact or other nonlinear analysis on a daily basis, and Dr. Urban points out, “It’s difficult to use a program sporadically, because you have to relearn it every time you use it. The capabilities of SOL 600 speed the nonlinear analysis process by enabling engineers to skip the creation of a separate model within Marc Mentat. Instead, by just clicking on the nonlinear preferences in Patran, engineers can perform nonlinear contact analysis in a program with which they are familiar.”

“The main value of SOL 600 is that people who are trained in MSC Nastran and Pataran can now do contact analysis with virtually zero training in MSC Marc. They are up and running, and can run contact analyses that would have required training in Marc and Mentat in the past. When they use SOL 600, they only have to remember the few steps they need to modify the model settings to run the contact analysis. It means that many more engineers can now run contact analysis,” says Dr. Urban.


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