2011

3D Direct Modeling: Removing Bottlenecks in Simulation

3D direct modeling provides a new alternative for geometry creation, simplification, and editing.

Geometry is a critical constituent in almost every simulation: representations must be sufficiently accurate for the given problem, possess the appropriate level of detail for pre-processing, and still be easily manipulated for iterative design modifications and optimization. Geometry creation and preparation can be the most labor-intensive stage of the CAE process, and that toil can detract from value-added work such as applying knowledge of materials, physics, and engineering to design problems and interpreting simulation results. We’ve worked closely with simulation providers to develop a product, SpaceClaim Engineer, designed to help engineers create concepts and prepare models for multiphysics without the hassles of traditional CAD.

altHistorically, CAE engineers have possessed limited options for geometry creation and manipulation. Traditionally, engineers would turn to CAD systems designed to create manufacturing documentation. Unfortunately, these systems proved inadequate for many common FEA and CFD use cases. In particular, the history-based modeling paradigm found in most traditional CAD solutions is, by design, intended to document modeling intent, requiring that operators lock down the models with a combination of constraints, inter-component references, and geometric relationships. The resulting models may only be edited as the CAD users intended, and therefore stakeholders outside of the core CAD teams often find these models difficult to repurpose, limiting thorough performance assessment and locking-in design intent prior to simulation. Additionally, production CAD geometry often includes features that must be removed before meshing or are unnecessary for the accuracy of a design study, and these features can be problematic to extract. Simply suppressing or removing them can change referenced geometry in unpredictable ways, effectively necessitating that models simplified in feature-based tools be geometrically compared to the originals. Finally, the complexity of most CAD systems required for detailed design can make using them inconvenient for many simulation users.

Recent developments in solid modeling have allowed us to provide a new alternative for geometry creation, simplification, and editing that can often better serve simulation users than the traditional history-based approach to CAD. This technology is typically called “direct modeling” in the CAD industry. Direct modeling uses a fundamentally different paradigm of representing and editing solid models, lends itself well to many CAE applications, and can remove geometry bottlenecks from simulation workflows. SpaceClaim combines direct modeling with special-purpose tools designed for simulation users’ unique needs.

De-featuring is a routine activity when working with existing data. Many features found in CAD models, such as rounds, holes, small features, and manufacturing marks, do not materially affect simulation results, yet can increase mesh sizes and lengthen solve times. SpaceClaim’s unique feature recognition capabilities can often automatically detect these features and remove them, because such de-featuring is a critical step during the normal editing process.

SpaceClaim can also add parameters to otherwise static geometry imported from CAD systems. Engineers can add different sets of parameters to models to generate design studies and closed-loop optimization with simulation results. This optimized geometry can be returned to CAD as the specification for further detailed design.

CAE engineers may find that direct modeling can help them navigate the engineering solution space more effectively, converging on optimal designs more quickly. When performing simulations on existing CAD data, direct modeling can accelerate geometry preparation, model validation, and optimization, and better communicate with the CAD team. It can ultimately create a more collaborative engineering environment, where more stakeholders can effectively converse in 3D. At SpaceClaim, we’re pleased to be making CAE-focused direct modeling available via direct integration with several popular FEA and CFD packages, as well as through several MDAO frameworks.

This work was done by Chris Randles, President and Chief Executive Officer of SpaceClaim. For more information, visit http://info.hotims.com/34458-130.

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