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IdealizationsOtherTechniquesforSimplifyingModelsLecture

Other Techniques for Simplifying Models

In addition to 2D model types and other idealizations there areadditional way of simplifying for analysis.

Analysis of Conceptual Parts Suppression

o By layer itemo Family Tableo Feature by feature (a la carte)

Cut Features

Conceptual Parts Simplified Representations Mirror/Cyclical symmetry constraints

Cut feature for Mirror symmetry constraint

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Simplified RepresentationLectureNotes

Other Techniques for Simplifying Models

In addition to 2D model types (Plane Stress, Plane Strain, and Axisymmetricmodels) and other idealizations (shells, beams, springs, and masses), there areother methods that can be employed to simplify Pro/ENGINEER models foranalysis. These methods include:

Suppression: Suppression enables you to remove features from the modelthat aren't important to the analysis by removing them from theregeneration sequence. Unlike deleting the features, the suppressedfeatures can be placed back in regeneration sequence by resuming them;a deleted feature would need to be recreated. Suppression can be doneby selecting features by using a layer, creating a family table instancewith features selectively suppressed, or feature by feature (a la carte).

Cut features: Cut features can be used to remove areas impertinent tothe analysis, or to trim away portions of a model in preparation forsymmetrical constraints (either mirror or cyclical symmetry constraints).

Conceptual models: By definition, a conceptual part contains just thebasic details of a design. As long as the most important aspects for theanalysis are included in the conceptual design, an analysis of this type ofdesign can be useful. Since a conceptual design is usually simple,analyses will run quicker on these types of models as opposed to the fullydesigned model. Additionally, results from the analyses can be used tohelp guide the further development of the design.

Simplified Representations: Simplified Representations can be of help insimplifying a model by enabling the creation of a representation of themodel that is simpler than the original but still preserves the originalmodel in an unaltered state. Simplified Representations do this byenabling the removal of non-salient design entities (Include versus

Exclude) without having to worry about the impact of parent/childrelationships. The bottom figure shows a bicycle model in one of itssimplified representations. The simplified representation enables theretention of components germane to an analysis of the frame, seat, andhandlebar assembly, while removing other components not necessary tothe analysis.

Aligning close parts: You may want to try aligning edges or surfaces on amodel that are close together when you can use engineering knowledge

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to make the assumption that doing so will not greatly impact the overallanalysis. Doing so enables for the creation of a simpler mesh for theanalysis model because the separate elements do not need to be createdon either side of the entities. Instead, geometric elements can cross overthe area that would otherwise be a discontinuity if the entities were not

aligned. Mirror and Cyclical constraints: Mirror and Cyclical constraints can be

used to reduce the overall number of elements required to complete ananalysis. You can use cut features to reduce the model to its symmetricsections as long as the model has geometric symmetry and all loads andconstraints are symmetric. The upper-right figure shows a bicycle seatthat has had a cut feature applied to it in preparation for a mirrorsymmetry constraint. In this case, the analysis should require about halfas many elements as the original model and should require about half ofthe computation resources for an analysis.