Parametric Modeling eLearning Series - CAE Associates · PDF fileParametric Modeling eLearning Series Part I - Geometry ... Parametric Finite Element ... There is a geometry processing

© 2015 CAE Associates

Parametric Modeling eLearning Series

Part I - Geometry

Pat Cunningham May 2015

2 www.caeai.com www.caeai.com

CAE Associates Inc.

Engineering Consulting Firm in Middlebury, CT specializing in FEA and CFD analysis.

ANSYS® Channel Partner since 1985 providing sales of the ANSYS® products, training and technical support.

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e-Learning Webinar Series

This presentation is part of a series of e-Learning webinars offered by CAE Associates.

You can view many of our previous e-Learning session either on our website or on the CAE Associates YouTube channel:

If you are a New Jersey or New York resident you can earn continuing

education credit for attending the full webinar and completing a survey which will be emailed to you after the presentation.

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CAEA Website Resource Library

Our Resource Library contains over 250 items including: — Consulting Case Studies — Conference and Seminar Presentations — Software demonstrations — Useful macros and scripts

The content is searchable and you can download copies of the material to review at your convenience.

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CAEA Engineering Advantage Blog

Our Engineering Advantage Blog offers weekly insights from our experienced technical staff.

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CAEA ANSYS® Training

Classes can be held at our Training Center at CAE Associates or on-site at your location.

CAE Associates is offering on-line training classes in 2015! Registration is available on our website.

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Agenda

Introduction to Parametric Modeling Part I – Parametric Geometry

— Feature based geometry: Pros and Cons — Direct geometry – Pros and Cons

Part II – Parametric Finite Element Modeling — Material coefficients — Mesh controls — Contact settings — Loads — Results

Part III – Using a Parametric Model for Optimization — Manual approach — Automated design studies — Direct Method — Response surface method

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Parametric Modeling with Finite Elements

A parametric finite element model is a useful tool for evaluating design sensitivity from a variety of levels.

— Design sensitivity is a term used to describe the relationship between changes in the input quantities of a system to the changes in the system response.

— Input quantities may consist of geometric dimensions, material coefficients and boundary conditions.

— Output quantities may include system mass as well as postprocessing entities like reaction forces, displacement and stress in a structural analysis.

Understanding which inputs the system is most sensitive to can help you increase the robustness of your design.

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Part I – Parametric Geometry

Obtaining or developing parametric geometry is often the most challenging part of parametric model development.

When your design intent is aligned with the parametric goals you can use a feature based CAD model as the parametric engine for the analysis.

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Feature Based Geometry

Most commercial CAD tools are feature based. Feature based systems have the following attributes:

— Planar (2D) sketches are used as the baseline for 3D operations like Extrude, Revolve, and Sweep.

— Both 2D sketch geometry and the 3D operations are parametric. — The geometry generation has a history. Regeneration of the geometry follows

the feature history. — Examples of feature based CAD tools include:

• SolidWorks • Creo Parametric (ProEngineer) • NX • AutoDesk Inventor

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Example: Lego man is getting on and needs a hip replacement.

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For this example we have access to the parent CAD tool and the parametric CAD file.

We begin at the CAD level by renaming the parameters we intend to use in the analysis so that we will recognize them in the analysis tool.

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Geometry Named Selections can also be defined at the CAD level and transferred to ANSYS using ANSYS 16.0 > Named Selection Toolbar.

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For this example we have access to the parent CAD tool and the parametric CAD file.

We use the ANSYS SolidWorks plugin to transfer geometry and parameters into ANSYS Workbench.

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Set the ANSYS geometry properties tom include the prefixed parameters and Named Selections.

Material Properties and coordinate systems can also be included.

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At this point we have to option to send the geometry directly to ANSYS Mechanical for analysis or do further defeaturing using ANSYS DesignModeler.

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Open the geometry in DesignModeler and add the CAD parameters to the Workbench Parameter Set.

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We can use the Symmetry tool to slice the geometry using the YZPlane.

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Use the Repair and Merge tools to search for geometry faults like slivers, holes, etc..

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Use Delete > Face Delete to remove unnecessary features.

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Add a fillet to the base of the round and add the radius to the parameter set.

Add the fillet radius to the project Parameter Set.

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Note that both CAD and DesignModeler parameters are available in the Parameter Set.

Relationships can be defined between the CAD and DesignModeler parameters. Typically the CAD parameter is the independent variable as the CAD operations come before DesignModeler in the history.

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When the analysis is fully defined with other input variables and result output variable a table of design points can be analyzed.

Design points can be analyzed in series or simultaneously using the Remote Solver Manager.

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To modify the geometry parametrically from Workbench change the current parameter values in the table and refresh the geometry row on the Project page.

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Refreshing the geometry row will update based on the new parameter values.

Note: The CAD tool is used to update the geometry to the new CAD parameter values. DesignModeler is used to update the new CAD geometry in succession.

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Direct Modeling with ANSYS SpaceClaim

What if none of the previous conditions exist? — The CAD model is not parametric (Parasolid, IGES, Step). — The model was provided in a format that you do not have access to. — The feature dimensions do not support the analysis goal.

In all of these cases a direct modeling approach using SpaceClaim may be more advantageous.

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SpaceClaim will read the CAD file directly (no need to use the original CAD system).

SpaceClaim can read a variety of file formats.

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Slicing for Symmetry, Face Deleting (Fill function) and other defeaturing operations are possible with SpaceClaim.

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Like sized features can be selected in bulk.

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Although the original CAD parameters are not present local parameters from Move and Pull operations can be defined.

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Local feature like chamfers and fillets can be added (parametrically) with the Pull tool.

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Local feature like chamfers and fillets can be added (parametrically) with the Pull tool.

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Locally defined SpaceClaim features can be controlled parametrically inside ANSYS Workbench.

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Summary

Feature Based modeling advantages: — Sharing of CAD parameters between the CAD and analysis tools. — Parametrically driven changes are reflected in the active CAD geometry. — Local DesignModeler parameters can be made a function of the CAD

parameters. — There is a geometry processing history that can be reviewed and edited.

Direct Modeling advantages:

— A parametric CAD file is not needed. — Local parameters can be shared with the analysis tool. — There is no dependence on the CAD design intent. — Good tool for up front concept modeling when the design intent is not yet

known.

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Stay tuned for Part II next month…

Introduction to Parametric Modeling Part I – Parametric Geometry

— Feature based geometry: Pros and Cons — Direct geometry – Pros and Cons

Part II – Parametric Finite Element Modeling — Material coefficients — Mesh controls — Contact settings — Loads — Results

Part III – Using a Parametric Model for Optimization — Manual approach — Automated design studies — Direct Method — Response surface method

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Parametric Modeling eLearning Series - CAE Associates · PDF fileParametric Modeling eLearning Series Part I - Geometry ... Parametric Finite Element ... There is a geometry processing

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