Plassotech 3g.author1 May, 2005 By: Jeffrey Rowe
Parametric simulation for validation and optimization.
When it comes to using fea (finite-element analysis) products for product validation and optimization, many come up short either in the number of additional, complex steps involved or in the true utility of the results. Product validation and optimization are two areas where PlassoTech's 3G.author shines as a parametric simulation tool.
For this review, I used 3G.author with SolidWorks 2005. The integration of the two is quite good with regard to overall function and bidirectional data associativity. Before we dive into 3G.author, let's take a quick look at the underlying meshing technology that sets it apart from most of the competition.
For a long time FEA software developers have sought different methods for estimating error and improving the accuracy of results by using various adaptive processes for refining meshes (the basis for FEA). The most widely used methods are the h- and p-adaptive refinements. 3G.author combines the two into an hp form that improves accuracy and processing time while eliminating many of the trade-offs associated with using either the h- or p-adaptive method.
Design Cases3G.author's interface is divided into three main parts: Project Tree, Model/Results Window and Design Control Panel. The Project Tree displays the models and design cases in a hierarchical view with nested levels of feature and attribute information. The Model/Results Window area displays separate windows for the model geometry and design case results as well as a browser window for collaboration. The Design Control Panel has two modes for showing design constraint criteria such as values and limits, and ranges for parameters.
To examine the performance of a model, all of the operating conditions the model experiences must be replicated. With 3G.author, users start this by importing a 3D CAD model and then building design cases for each operational condition to be examined. Design cases are sets of parameters and conditions that allow the evaluation of different parametric dimensions, loading conditions and materials. Each design case can be checked separately, so multiple people can collaborate and evaluate different aspects of a project simultaneously. Different types of design cases can have various attributes to define the operating conditions.
Refining a design is aided by the ability to analyze the results of one design case to determine the relationships between the criteria before proceeding to the next iteration of the design.
Projects and Parametric DimensionsA project must be open before a model can be imported. The new model is added to the bottom of the project tree. If the CAD application that created the file is not on the workstation, a dialog box appears to identify a peer machine on the network that has the application and 3G.agents installed. The file must also be on the network and visible to the peer machine.
A model must be fully resolved before importing, without any warnings or messages. If the CAD program must resolve anything, the import fails and some action may be needed on the peer machine.
Parametric dimensions allow users to vary a model's dimensions to see the updated geometry and evaluate various configurations for a design case. The CAD program updates the geometry of all corresponding features, so design intent is maintained. Parameter ranges must be chosen carefully to produce model configurations with compatible feature structures and topology compared with the base model.
Simulation SpecificsRunning a simulation evaluates the FEA results for all the combinations of variables defined in a study.
For assemblies, users can exclude a part or subassembly from simulation by opening the assembly tree under the function study (project tree view) and excluding a given component. Also, users can preview a mesh before running a simulation. After the simulation runs, you evaluate the results in the Active Solution Space.
To view results, double-click on the Results node of the Project Tree or right-click on the node and select View Graphics. A Results window opens, displaying the design case's results in the foreground. The user is notified when the results are interpolated. Multiple results and model windows can be tiled or cascaded to see the differences between simulations (figure 1).
Figure 1. When displaying a model, Plassotechs 3G.author lists design cases with checkmarks to evaluate criteria. After a simulation, colors indicate when something is out of range.
To change the type of information displayed, select a new component from the pull-down list on the Results toolbar. The color map denotes the magnitude of the component. To animate simulation results and view the different iterations of a simulation, use the sliders in the Design Control Panel (figure 2).
Figure 2. To optimize in 3G.author, users can set limits on some constraint values and minimize others to filter the results. When an optimized solution displays, the sliders at the bottom of the screen can be moved to quickly evaluate conditions either above or below the optimized state.
For $5,000, the software supports the following types of analysis: static stress, frequency, thermal, thermal stress, nonlinear thermal, multimaterial assembly analysis with nonlinear contact, multidisciplinary optimization, advanced meshing option, shell-based simulations, fully adaptive, parametric load and materials.
As I said at the outset, I used SolidWorks 2005 with 3G.author, but it can also be used with data from Inventor, CATIA, Solid Edge, Pro/ENGINEER, Parasolid, SAT, STEP and IGES. It's a powerful parametric simulation tool that is especially well suited to design validation and optimization.
Jeffrey Rowe is an independent mechanical design and technical communications consultant. With offices in Colorado and Michigan, he can be reached at 719.539.8549 or jrowe@cairo west.com
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