Performing FEA on CAD Models through Reliable, Seamless Data Exchange

By James Shaw

This image shows how InCAD technology captured G3 Genuine Guide Gear Inc.’s exact SolidWorks geometry for the G3 AviMATRIX avalanche shovel (left) in ALGOR’s CAD Solid Model environment (right) in order to perform FEA on the model. Model courtesy of James Shaw, G3 Genuine Guide Gear Inc.

CAD software packages like SolidWorks offer valuable modeling and visualization capabilities for engineers creating products that must be reliable and safe. To learn how products will perform in the real world, however, finite element analysis (FEA) software must also be used in the design cycle. ALGOR’s FEA software offers reliable, seamless data exchange through its InCAD family of products that support popular CAD solid modelers such as Autodesk Inventor, CADKEY, Mechanical Desktop, Pro/ENGINEER, Solid Edge and SolidWorks.

Among several FEA packages I found that would work directly with SolidWorks geometry, ALGOR offered especially feature-rich software. Its InCAD Designer for SolidWorks package performs linear static stress, linear dynamic and thermal analyses. Optional analysis add-ons include Mechanical Event Simulation (MES) for combining motion and stress analysis in one program, nonlinear material models and multiphysics capabilities for simultaneously analyzing thermal, electrostatic and fluid flow phenomena along with stress.

I decided to purchase the ALGOR software after viewing an on-line demonstration showing a full analysis performed within only about 10 minutes. This presentation, which is one of many software demonstration Webcasts available at www.eTechLearning.com, shows those without FEA software experience how easy the software is to learn and use.

The software loaded quickly and the Help functions, tutorials and web sites (www.ALGOR.com and www.eTechLearning.com) provided most of the answers when questions arose, including how to generate a mesh and how to set analysis parameters. A User’s Guide can run simultaneously with the FEA software for quick reference, and step-by-step, on-line tutorials and Webcasts are directly accessible by clicking on selections in the Help menu.

Upon starting the program, a dialog in which the user designates what model to open automatically appears. I selected one of my SolidWorks models, and it immediately opened in the FEA software with a "Create Surface Mesh" dialog that provided a slider control for mesh size selection and options for automatic solid meshing.

Once surface and solid meshes were generated, loads and constraints were applied in ALGOR’s FEA Editor environment.

I used all default mesh settings for the first analysis of my model with the software’s automatic hybrid approach that consists of eight-node brick elements and tetrahedral elements. This seemed to be the easiest way for a first-time FEA software user like myself to get quick analysis results. Other available solid meshing options include "All 8-Node Bricks" and "Tetrahedral."

If a part is properly modeled in CAD, a mesh starts generating in seconds. If a model has any problems, the software instantly shows it by automatically retrying the meshing procedure. In this way, the FEA software checks engineers’ modeling and makes sure that everything in a model is tied together and has continuous surfaces.

The user-friendly interface enables choices to be made by pointing and clicking on menu options or by using extensive right-click functions to pop up dialogs, and the reliable default values and selections assist new users in learning to use the software.

After meshing the model, users work in the FEA Editor environment to set up the desired analysis. This includes choosing the type of analysis, elements and materials as well as setting loading and constraints. The model tree view displays a red "X" on each field that must be completed prior to running an analysis, which is quite helpful. Within the FEA Editor environment, required fields include "Element Type" and "Material". The user can choose and specify parameters for an analysis type (Linear, Heat Transfer, etc.) as well as choosing to use truss, beam, membrane, 2-D, brick, gap, plate or tetrahedral elements and selecting element materials from the ALGOR Material Library. The Material Library Manager also offers the option of adding new materials and their properties as needed to catalog exact material specifications.

An integrated Results environment that offers full user-controlled graphical results viewing is in the process of being implemented in all ALGOR software packages.

In terms of applying loads and constraints, I used surface and/or nodal loads in various runs that ranged between 30 and 100 pounds in different directions and constrained the front, flat surface and leading edge of the model. Impact loads were estimated as being twice the corresponding static loads. Once all red "X" marks disappeared from the FEA Editor tree view, I performed a linear static stress analysis.

When the analysis finished, I viewed full-color result contours on my model in the post-processing environment. The von Mises stress, maximum principal stress and deflection results proved most helpful and interesting for this analysis. I’m looking forward to using the new integrated Results environment, which is in the process of being implemented in all ALGOR software packages and will offer a smoother workflow within the package.

Following the process outlined above, I analyzed about 10 iterations of my SolidWorks model to see how changes would affect product performance. I could do so very quickly, assuming I was using similar loading and other parameter settings, so model alterations were no longer based on guesswork alone and I could add a feature or a different material and see what happened. ALGOR now offers fully associative CAD/CAE operation with SolidWorks that enables changes made to the SolidWorks geometry to be automatically reflected and updated in the FEA model. Its MES software that virtually replicates how products will behave in the real world is something I hope to add to my design toolbox in the future.

In short, I found that not only is ALGOR software good for engineers who are knowledgeable about FEA, but it’s also quite effective for people like me who are new to this type of application.
 

James Shaw is an engineer with G3 Genuine Guide Gear Inc., a manufacturer of backcountry ski equipment based in North Vancouver, BC, Canada.

Click here for more on how G3 Genuine Guide Gear Inc. used ALGOR software.