Autodesk Inventor Simulation 2010 Getting Started Part No.
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Contents Stress Chapter 1 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Get Started With Stress Analysis . . . . . . . . . . . . . . . . . . 3 About Autodesk Inventor Simulation . . . . . . . . . . . . . . . . . . . 3 Learn Autodesk Inventor Simulation . . . . . . . . . . . . . . . . . . . . 4 Use Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Use Stress Analysis Tools . . . . . . . . . . . . . . . . . . . . . . . . . .
Add Loads . . . . . . . . . Add Contact Conditions . Generate a Mesh . . . . . Run the Simulation . . . . Run Modal Analysis . . . . . . . Chapter 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 . 19 . 20 . 20 . 21 View Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Use Results Visualization . . . . .
Simulation Assumptions . . . . . . Interpret Simulation Results . . . . Relative Parameters . . . . . . Coherent Masses and Inertia . Continuity of Laws . . . . . . Chapter 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 . 45 . 45 . 46 . 46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Stress Analysis Part 1 of this manual presents the getting started information for Stress Analysis in the Autodesk Inventor® Simulation software. This add-on to the Autodesk Inventor assembly, part, and sheet metal environments provides the capability to analyze the static stress and natural frequency responses of mechanical designs.
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Get Started With Stress Analysis 1 Autodesk Inventor® Simulation software provides a combination of industry-specific tools that extend the capabilities of Autodesk Inventor® for completing complex machinery and other product designs. Stress Analysis in Autodesk Inventor Simulation is an add-on to the Autodesk Inventor assembly, part, and sheet metal environments. Static Analysis provides the means to simulate stress, strain, and deformation.
Learn Autodesk Inventor Simulation We assume that you have a working knowledge of the Autodesk Inventor Simulation interface and tools. If you do not, use Help for access to online documentation and tutorials, and complete the exercises in the Autodesk Inventor Simulation Getting Started manual. At a minimum, we recommend that you understand how to: ■ Use the assembly, part modeling, and sketch environments and browsers. ■ Edit a component in place.
■ In the graphics window, right-click, and then click How To. The How To topic for the current tool is displayed. Use Stress Analysis Tools Autodesk Inventor Simulation Stress Analysis provides tools to determine structural design performance directly on your Autodesk Inventor Simulation model. Autodesk Inventor Simulation Stress Analysis includes tools to place loads and constraints on a part or assembly and calculate the resulting stress, deformation, safety factor, and resonant frequency modes.
With the stress analysis tools, you can: ■ Perform a structural static or modal analysis of a part or assembly. ■ Apply a force, pressure, bearing load, moment, or body load to vertices, faces, or edges of the model, or import a motion load from dynamic simulation. ■ Apply fixed or non-zero displacement constraints to the model. ■ Model various mechanical contact conditions between adjacent parts. ■ Evaluate the impact of multiple parametric design changes.
from a basic or fundamental analysis. Performing this basic analysis early in the design phase can substantially improve the overall engineering process. Here is an example of stress analysis use: When designing bracketry or single piece weldments, the deformation of your part may greatly affect the alignment of critical components causing forces that induce accelerated wear. When evaluating vibration effects, geometry plays a critical role in the natural frequency of a part or assembly.
The stress analysis provided by Autodesk Inventor Simulation is appropriate only for linear material properties where the stress is directly proportional to the strain in the material (meaning no permanent yielding of the material). Linear behavior results when the slope of the material stress-strain curve in the elastic region (measured as the Modulus of Elasticity) is constant. The total deformation is assumed to be small in comparison to the part thickness.
Interpret Results of Stress Analysis The output of a mathematical solver is generally a substantial quantity of raw data. This quantity of raw data would normally be difficult and tedious to interpret without the data sorting and graphical representation traditionally referred to as post-processing. Post-processing is used to create graphical displays that show the distribution of stresses, deformations, and other aspects of the model.
by an uniaxial stress test, then the real stress system is related by combining the six stress components to a single equivalent stress. Maximum and Minimum Principal Stresses According to elasticity theory, an infinitesimal volume of material at an arbitrary point on or inside the solid body can be rotated such that only normal stresses remain and all shear stresses are zero.
fatigue failure, which is not simulated by Autodesk Inventor Simulation Stress Analysis. Always, use engineering principles to evaluate the situation. Frequency Modes Use modal frequency analysis to test a model for its natural resonant frequencies (for example, a rattling muffler during idle conditions, or other failures). Each of these incidences may act on the natural frequency of the model, which, in turn, may cause resonance and subsequent failure.
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Analyze Models 2 After you define your model, you use the stress analysis environment to prepare the model for analysis. You define the materials, loads, and constraints for the condition you want to test, and establish contact conditions and mesh preferences. Then, you perform an analysis, also called simulation, of the model. This chapter explains how to define materials, loads, constraints, contacts, and meshing, and then run your analysis.
8 Run the simulation. 9 View and Interpret the Results When you make modifications to the model or various inputs for the simulation, it can be necessary to update the mesh or other analysis parameters. A red lightning bolt icon next to the browser node indicates areas that need an update. Right-click the node and click Update to make them current with respect to the modifications. For the Results node, you must run the Simulate command to update results.
5 Click OK. The new simulation populates the browser with analysis nodes. Exclude Components In assemblies, some components have no bearing on the simulation. You can exclude the components. Right-click the component node and click Exclude from simulation. Exclusion in a simulation has no effect on the assembly in the modeling environment. In parts, you can exclude part features, such as small fillets and cosmetic features that have no bearing on the performance of the part.
Specify Material The stress analysis environment provides the means to override materials for any component. The default material provided in Inventor templates is not completely defined for simulation purposes. When modeling your components, use materials that are appropriate and completely defined, particularly if you are going to use simulation. 1 Click Assign Materials. This step is optional based on the materials used for the components.
Constraint Constraint-Specific Information Frictionless Constraint Apply a frictionless constraint to a flat or cylindrical surface in the part. Frictionless constraints prevent the surface from moving or deforming in the normal direction relative to the surface. To add a constraint: 1 Click the constraint command corresponding with the type of constraint you want to assign. 2 The select command is active and you can begin selecting the geometry related to the constraint type.
Add Loads To simulate conditions your design can encounter, you add force loads to areas where such forces can be encountered. There are a variety of load types to use. The following list explains the available load types. Load Load-Specific Information Force Apply a force to a set of faces, edges, or vertices. When the force location is a face, the direction is automatically set to the normal of the face, with the force pointing to the inside of the part.
Load Load-Specific Information Gravity Specifies the direction of gravitational load on the model. Select a face to define the direction or use Vector Components to precisely control the direction. Cylindrical selections provide an axial direction. To add a load, you must: 1 Click the load command corresponding to the load type you want to add. 2 The selection command is active so you can select the geometry appropriate to the load you are defining. 3 Specify the load parameters.
2 Specify the contact type. 3 Select the appropriate entities for the contact type. If other components are obscuring the component you want to select use Part selection option to select the part first, then refine your selection thereafter. Generate a Mesh You can accept the default mesh settings and proceed right to the simulation. At times there will be areas where you would like a mesh with greater density. To manage this you can adjust the mesh settings or use a local mesh control.
When ready, click Run to start the simulation calculations. Run Modal Analysis In addition to the stress analysis, you can perform a modal frequency analysis to find the natural frequencies at which your part vibrates, and the mode shapes at those frequencies. Like stress analysis, modal analysis is available in the stress analysis environment. You can do a natural frequency analysis independent of a stress analysis.
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View Results 3 After you analyze your model under the stress analysis conditions that you defined, you can visually observe the results of the solution. This chapter describes how to interpret the visual results of your stress analyses. Use Results Visualization When the simulation completes its computations, the graphics region updates to show: ■ 3D Volume plot and result type. ■ Smooth Shading showing the distribution of stresses. ■ Color bar indicating the stress range.
The various results sets are seen by expanding the Result node to reveal the child nodes. For example, when you run a static analysis, child result nodes for Von Mises Stress, 1st principal stress, Displacement, Safety Factor, and so on populate the browser. To view the different results sets, double-click the browser node. While viewing the results, you can: ■ Change the color bar to emphasize the stress levels that are of concern. ■ Compare the results to the undeformed geometry.
Probe for values at specific points. ■ Edit the Color Bar The color bar shows you how the contour colors correspond to the stress values or displacements calculated in the solution. You can edit the color bar to set up the color contours so that the stress/displacement is displayed in a way that is meaningful to you. Edit the color bar 1 On the ribbon, click Stress Analysis tab ➤ Display panel ➤ Color Bar.
5 By default, the color bar is positioned in the upper-left corner. Select an appropriate option under Position to place the color bar at a different location. 6 For Size, select an appropriate option to resize the color bar, and then click OK. The color bar settings are applied on a per result basis. Read Stress Analysis Results When the analysis is complete, you see the results of your solution. If you did a stress analysis, the Von Mises Stress results set displays.
3rd Principal Stress The 3rd principal stress acts normal to the plane in which shear stress is zero. It helps you understand the maximum compressive stress induced in the part due to the loading conditions. Displacement The Displacement results show you the deformed shape of your model after the solution. The color contours show you the magnitude of deformation from the original shape. The color contours correspond to the values defined by the color bar.
Set Results Display Options While viewing your results, you can use the following commands located on the Result and Display panels to modify the features of the results display for your model. Command Used to Same Scale Maintains the same scale while viewing different results. Color Bar Displays the Color Bar settings dialog box where you adjust the color bar display parameters. Smooth Shading Displays color changes using a blended transition.
Command Used to Probe Activates the Probe command. You place probes as needed in areas of interest to display the stress values for that point. Display Probe Labels Toggles the visibility of probe labels. Displacement Scale Displays a preset list of displacement exaggeration scales. Choose a scale that suits your need. Mesh View Displays the element mesh used in the solution in conjunction with the result contours. Also displays the mesh over the undeformed model.
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Revise Models and Stress Analyses 4 After you run a simulation for your model, you can evaluate how changes to the model or analysis conditions affect the results of the simulation. This chapter explains how to change simulation conditions for the model and rerun the simulation. Change Model Geometry After you run an analysis on your model, you can change the design of your model. Rerun the analysis to see the effects of the changes.
6 At the bottom of the window, click the assembly tab. Your component is updated. 7 Some portions of the simulation may now be out of date with reference to the change. You must update these in order to have current analysis data. If an update is necessary, right-click the Contacts node, and click Update. 8 Repeat step 7 for each area that requires it. Then click Simulate to update the results.
2 Click the selection arrow on the left side of the dialog box to enable feature picking. You are initially limited to selecting the same type of feature (face, edge, or vertex) that is currently used for the load or constraint. To remove any of the current features, CTRL-click them. If you remove all of the current features, your new selections can be of any type. 3 Click the Direction Selection arrow to specify the change of direction using model geometry.
Update Results of Stress Analysis After you change any of the simulation conditions, or if you edit the part geometry, the current results are invalid. A lightning bolt symbol next to the results node indicates the invalid status. The Update command is located in the node context menu and is enabled. Update stress analysis results ■ Right-click the node that needs an update, and click Update. New results generate based on your revised solution conditions.
Generate Reports 5 After you run an analysis on a part or assembly, you can generate a report that provides a record of the analysis environment and results. This chapter tells you how to generate and interpret a report for an analysis, and how to save and distribute the report. Run Reports After you run a simulation on a part or assembly, you can save the details of that analysis for future reference.
Interpret Reports The report contains model information, project information, and simulation results. Model Information The Model information contains the model name, version of Inventor, and the creation date. Project Info The Project Info includes the following: ■ Summary, which includes the Author property. ■ Project properties, which includes part number, designer, cost, and date created.
Advances settings This section contains: ■ Average Element size ■ Minimum element size ■ Grading Factor ■ Maximum Turn Angle ■ Create Curved Mesh Elements setting value ■ Ignore Small Geometry value Material(s) ■ Material name ■ General properties ■ Stress properties ■ Thermal properties ■ Part names, if an assembly report Operating conditions ■ Each force by type and magnitude, with images ■ Each constraint by type with images.
Save and Distribute Reports The report is generated as a set of files to view in a Web browser. It includes the main HTML page, style sheets, generated figures, and other files listed at the end of the report. Saved Reports By default reports are saved in the same location as the model being analyzed. The report images are saved in a directory name Images in the same location as the model being analyzed. Be careful when you name a report.
Manage Stress Analysis Files 6 Running a stress analysis in Autodesk Inventor® Simulation creates separate files that contain the stress analysis information. In addition, the model file is modified to indicate the presence of the stress files and the name of the files. This chapter explains how the files are interdependent, and what to do if the files become separated.
Resolve Missing Files Under certain circumstances, simulation files can be relocated or missing when working with a model. When you first open a model file, the Resolve Link dialog box displays. You can browse to the location of the simulation files, or you can choose to skip them. If you skip the files, the Simulation environment can re-compute the files if necessary.
Dynamic Simulation Part 2 of this manual presents the getting started information for Dynamic Simulation in the Autodesk Inventor® Simulation software. This application environment provides tools to predict dynamic performance and peak stresses before building prototypes.
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Get Started with Simulation 7 AutodeskInventor® Simulation provides tools to simulate and analyze the dynamic characteristics of an assembly in motion under various load conditions.
■ Calculate the force required to keep a dynamic simulation in static equilibrium. ■ Convert assembly constraints to motion joints. ■ Use friction, damping, stiffness, and elasticity as functions of time when defining joints. ■ Use dynamic part motion interactively to apply dynamic force to the jointed simulation. ■ Use Inventor Studio to output realistic or illustrative video of your simulation.
Understand Simulation Tools Large and complex moving assemblies coupled with hundreds of articulated moving parts can be simulated. Autodesk Inventor Simulation Simulation provides: ■ Interactive, simultaneous, and associative visualization of 3D animations with trajectories; velocity, acceleration, and force vectors; and deformable springs. ■ Graphic generation tool for representing and post-processing the simulation output data.
Coherent Masses and Inertia Ensure that the mechanism is well-conditioned. For example, the mass and inertia of the mechanism should be in the same order of magnitude. The most common error is a bad definition of density or volume of the CAD parts. Continuity of Laws Numerical computing is sensitive toward incontinuities in imposed laws. Thus, while a velocity law defines a series of linear ramps, the acceleration is necessarily discontinuous.
Simulate Motion 8 With the dynamic simulation or the assembly environment, the intent is to build a functional mechanism. Dynamic simulation adds to that functional mechanism the dynamic, real-world influences of various kinds of loads to create a true kinematic chain. Understand Degrees of Freedom Though both have to do with creating mechanisms, there are some critical differences between the dynamic simulation and the assembly environment.
And, in the dynamic simulation environment, you build joints to create degrees of freedom. Understand Constraints By default, certain constraints that exist in the assembly are automatically converted to joints when dynamic simulation. This eliminates extensive work on your part in creating joints. NOTE Autodesk Inventor Simulation Simulation converts constraints that have to do with degrees of freedom, such as Mate or Insert, but does not convert constraints that have to do with position, such as Angle.
As you work through the following exercises, save the assembly periodically. Convert Assembly Constraints Notice that the assembly moves just as it did in the assembly environment. It seems to contradict preceding explanations, however, the motion you see is borrowed from the assembly environment. Even though you are in Autodesk Inventor Simulation Simulation, you are not yet running a simulation. Since a simulation is not active, the assembly is free to move.
5 On the Simulation Player, click Activate Construction Mode . It exits the simulation mode and returns to the Dynamic Simulation construction mode. In construction mode, you perform such tasks as creating joints and applying loads. Automatically convert assembly constraints 1 On the ribbon, click Dynamic Simulation tab ➤ Manage panel ➤ Simulation Settings.
3 Right-click the Srf1 node and click Visibility. The Bevel Gear construction surface displays. We use this surface to help define the gear relationship. 4 At the right end of the ribbon panel, click Return. You are placed back in the simulation environment. 5 On the ribbon, click Dynamic Simulation tab ➤ Joint panel ➤ Insert Joint . 6 In the pull down list, select Rolling: Cone on Cone. 7 The Component selector command is active and waiting for input.
Run Simulations The Simulation Player contains several fields including: 1 Final Time 2 Images 3 Filter 4 Simulation Time 5 Percent of Realized Simulation 6 Real Time of Computation Simulation Panel Final Time field Controls the total time available for simulation. Images field Controls the number of image frames available for a simulation. Filter field Controls the frame display step. If the value is set to 1, all frames play. If the value is set to 5, every fifth frame displays, and so on.
TIP Click the Screen Refresh command to turn off screen refresh during the simulation. The simulation runs, but there is no graphic representation. Before you run the simulation, make the following adjustments. Set up a simulation 1 On the Simulation Player, in the Final Time field, enter 0.5 s. TIP Use the tooltips to see the names of the fields in the Simulation Player. 2 In the Images field, enter 200. Increasing the image count improves the results when viewed using the Output Grapher.
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Construct Moving Assemblies 9 To simulate the dynamic motion in an assembly, define mechanical joints between the parts. This chapter provides basic workflows for constructing joints. Retain Degrees of Freedom In some cases, it may be appropriate that certain parts move as a rigid body and a joint is not required. As far as the movement of these parts is concerned, the welded body functions like a subassembly moving in a constraint chain within a parent assembly.
6 Select circular sketch (2) on the roller component. 7 Click Apply. As you can see, sketch geometry can be used to help define the simulation. 8 Drag the Follower until the roller contacts the cam. Notice it does not penetrate. The 2D contact established a mechanical relationship between the two components. 9 Set the properties for the 2D contact and display the force vector. In the browser, right-click the 2D Contact joint and click Properties. 10 Set the Restitution values to 0.0.
Add Joints The Follower is designed to slide through a portion of the Guide component. However, to hold the Follower Roller against the Cam, specify a spring between the Follower and Guide components. Dynamic Simulation has a joint for doing that and more, the Spring/Damper/Jack joint. 1 On the ribbon, click Dynamic Simulation tab ➤ Joint panel ➤ Insert Joint and in the list, select Spring / Damper / Jack joint.
Expand the dialog box and set: ■ Radius = 5.2 mm ■ Turns = 10 ■ Wire Radius = .800 mm 6 Click OK. The spring properties and graphical display update. Define gravity 7 In the browser, in the External Loads folder, right-click Gravity and click Define Gravity. Alternatively, you can double-click the Gravity node. If necessary, clear the Suppress check box. 8 Select the Case edge, as shown in the following image, to specify a vector for gravity.
3 Click Edit Joint Motion , and check Enable imposed motion. 4 Verify that Velocity is the selected Driving option. 5 In the input field, click the arrow to expand the input choices and click Constant Value. Specify 10,000 deg/s 6 Click OK. Run Simulations Because the simulation is of a high speed device, modify the simulation properties. TIP Use the tooltips to see the names of the fields on the Simulation Player Setting simulation options 1 On the Simulation Player, Final Time field, enter .
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Construct Operating Conditions 10 This chapter demonstrates how to complete the motion definitions so that the simulation reflects operating conditions. Complete the Assembly If the RecipSaw-saved.iam assembly is not open, you need to open the file to continue. As you can see, though we have the saw body, we do not have the blade components. To add the blade components it is not necessary to leave the simulation environment.: 1 Click the Assemble tab to display the assembly ribbon.
4 In the browser, expand the Blade set assembly node to expose the components. 5 Select the Scottish Yoke component. On the Quick Access Toolbar, change the color to Chrome. NOTE If you receive a Design View Representation message about color associativity, select Remove associativity and click OK. 6 Add a mate constraint between the Scottish Yoke and Guide to position the yoke on top of the guide.
7 Add a second mate constraint between the two components to position the yoke within the guide rails. In the browser under Standard Joints, a prismatic joint was created based on adding those constraints. Add Friction Add friction and complete the yoke-guide relationship 1 In the browser, right-click Blade set.iam and click Flexible. By setting the assembly to Flexible, the assembly is placed into the welded group folder.
3 Click the dof 1 tab. Click the joint forces command . Click Enable joint force. Enter a Dry Friction coefficient of 0.1 and click OK. 4 We need to add a constraint to position the Scottish Yoke with respect to the crank assembly. Set the browser view to Model and expand the Blade set.iam node. 5 Expand the Scottish Yoke node and click the Constraint command. 6 In the browser, select Work Plane3 under the Scottish Yoke component.
2 In the ribbon bar, click the Dynamic Simulation tab to display the simulation commands. Now we’ll add the sliding joint. 3 In the Joint panel, click Insert Joint. In the pull down list, select Sliding: Cylinder Curve. For input 1 select the blade clamp slot profile on which the follower rides. 4 For input 2, select the Follower cylinder face that rides in the slot. Click OK. 5 Unlock the prismatic joint. That completes this chapter on adding components and joints to the assembly.
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Index Simulation Panel 52 dynamic simulation 43 assumptions 45 coherent masses and inertia continuity of laws 46 relative parameters 45 results 45 A analyses meshing 8 modal 21 post processing 9 reports 35 rerunning on edited designs results, reading 23, 26 solving 7 types, setting 33 updating 34 vibration 11 analysis (.
L load symbols 32 displaying 28, 33 loads browser display 17 deleting, adding, and editing M meshes creating 8 displaying 29 Minimum command 28 modal analyses 11, 21 model geometry, editing 31 modes frequency 11 result options 21 S N natural resonant frequencies 11 O Output Grapher 61 P panel bar, Stress Analysis 13 post processing analyses 9 preprocessing 8 prerequisites for exercises 4 R relative parameters 45 Report command 35 reports printing and distributing 38 saving 35 resonant frequency anal
V vibration frequency analyses von Mises stress 10 W 21 welded bodies 55 workflows running modal analyses 21 Index | 69
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