Design Optimization via SimulationPeter Maxfield - AutodeskMA314-4Using the latest FEA suite of tools, learn how to optimize your design for the best geometry sizing without sacrificing quality.Key Learning Introduction to the FEA tools in AutoCAD Inventor Professional 2010 Parametric Tables Optimization Promotion of changes back to the model

Insert Class Title as per Title PageDesign Optimization Via Simulation

About the Speaker:Peter has been with Autodesk, Inc. since 2003 as a Product Design Lead. During that time, he has worked several aspects of Autodesk Inventor, notably the Assembly and Simulation environments. He has also contributed to Framework, Routed Systems, Frame Generator, and Vault. Previously, Peter worked as a Mechanical Engineer for Praxis, and as a Product Designer for PTC. He earned his B.S. degree in Mechanical Engineering at Cornell University.peter.maxfield@autodesk.com

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IntroductionAutodesk Inventor Professional provides a rich suite of Simulation tools, including Stress Analysis (FEA) and Dynamic Simulation (Rigid Motion Dynamics). In this class, we will explore the Parametric Table and Optimization tools new to R2010. A basic understanding of FEA is required, as well as core Inventor modeling skills.

Overview AIP R2010 introduces a modern new stress analysis solver and greatly enhanced functionality. Those familiar with previous releases will see the same core capabilities: Linear Static & Modal Frequency response Loads (Forces & Moments) Constraints Contacts ReportsThe most notable change is the ability to conduct FEA studies in the context of assemblies. Other new features include: Multiple Simulations Material Overrides Component Exclusion Localized Control for Mesh & Solver Convergence Adaptive solver for mesh density (h) & polynomial order (p) Parametric Tables & Plots Optimization Ribbon User InterfaceCombine these tools with an incredible fast solver, and you have a very powerful suite which can aide built-in quality and reduced prototyping from the very first stages of design.Parametric StudiesA new concept to Inventor Stress Analysis is the notion of parametric studies. In R2010, any non-driven model parameter can be used to explore design alternatives. Adjusting the values within specified ranges allow the user to witness the design response, without committing permanent changes to the native CAD design. Simulation TypeIn the Simulation Properties panel, the Design Objective should be changed from Single Point to Parametric Dimension:

Parametric SpaceAs many parameters from as many components as desired can be added to the table for a given Simulation. The user designates a range of values for each parameter. Here is an example of two parameters being adjusted: wall Thickness (two values) and the Rib Offset from the base (three values; note the conditional feature which adds a second rib once a specified offset is reached).Rib Offset

Thickness

In total, there are six possible configurations. Not a large amount, but each of these could have a very different response under the same loading conditions. If we add just one additional parameter, the internal Thickness of the webbing, and give it a range of three values, we now have a space of 18 potential combinations. Notice how easily the total number can grow with only a few parameters with limited ranges.

The concept can expand further with multiple components, larger ranges, conditional features, and iLogic. The possibilities are endless!Parametric Table The user manages these configurations with the Parametric Table. It can be launched from the Manage panel of the Ribbon:

The lower half guides the parametric ranges:

Here we see the component names, feature names, parameter names, range values, sliders, current value, and units. The sliders are what allow a user to change the active configuration.Adding a ParameterParameters can be added by choosing Show Parameters in the browser from a given component or feature.

This will expose all sketch-based parameters in the graphics, and also display a dialog listing all of the parameters. Toggle the checkbox to include a parameter in the table.

Note, driven parameters are not available. Geometry GenerationThere are three important items to note at this time. The first is that all of these configurations are only witnessed in the Stress Analysis environment. The native CAD models, and any dependent documents such as drawings or assemblies, are not affected. The second is that the native Inventor modeling kernel is used to generate each configuration. That is, any children features, assembly constraints, or other dependencies will update properly for each Parametric Study. Similarly, FEA objects will update their placements properly. For instance, a force on the end of a feature will move with that feature if the parametric table causes it to change size. The third item to note is that these configurations will only be generated when the user makes a specific request. In our example thus far, 18 configurations for even a relatively simple part could take some time. The user has a set of tools to choose how exhaustively these configurations should be built. They are accessed from the right-mouse context menu for a given row in the table:

The three Generate commands allow a user to build just the current configuration, the range for the currently selected parameter, or the entire space of configurations. Smart SamplingThe real power of the Parametric Studies is the ability to provide useful information in an efficient manner, without exhaustively solving each and every configuration. Referring back to the 3D space of our three-parameter example, the default behavior of the system is to solve only the edges of the space. That is, each parameter will be evaluated through its range, while the other parameters will be held in their base value.

In our example, this means only 6 simulation solves will be performed; one third the total!To report results for configurations that do not lie along the edges, the system will interpolate results. This can be done due to the linear nature of the solver. The user can make specific solve requests for any configuration, or request an exhaustive solve of the entire space.Note, only the values designated in the ranges can be interpolated. Further, values added outside the current ranges will not be automatically interpolated. PlotsTo get a sense for how a given parameter is affecting a specific Result, an XY Plot can be generated. This can provide trending information which can help gauge if a given parameter has a high- or low-impact, with all other parameters held constant.

In this example, the Rib Offset is seen to increase the Safety Factor from about 1.8 to over 4.0 in the range specified. This is expected, given the addition of a second rib at the extreme value. OptimizationThus far we have seen how Inventor Professional can provide alternative geometry experimentation and see the design response quickly and accurately.The upper half of the Parametric Table tool assists the user in finding the optimal configuration for a set of goals. By declaring Design Constraints, the system can automatically seek goals such as: Minimize Upper / lower Limit Stay in / out of rangeThis relieves the user from having to manage all of the potential outcomes and their system responses, and instead focuses attention on achieving a specific design goal.

In this example, the Maximum Von Mises stress is being queried, with a goal of minimizing. The green check mark in the Result value indicates that the goal is realized by finding the proper configuration.From Experiment to ProductionOnce a satisfactory configuration has been found, the user can easily update the master CAD model with a simple right-mouse command Promote configuration to model. Parametric Loads and MaterialsRelease 2010 does not provide direct support for Loads or Material adjustments within the Parametric Table. However, by copying a given Simulation, and making adjustments to the loads and/or Materials, then solving multiple Simulations at the same time, an effective comparison can be made.

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