Understanding simulation results

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In this video, you’ll:

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evaluate credibility of results of setup,

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evaluate credibility of result requirements,

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and interpret model-induced stress concentrations.

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Stress analysis in Fusion 360 is based on the finite element method,

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which breaks down a design into a mesh of finite elements and performs calculations on them.

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However, the accuracy of these results can be unreliable if some key assumptions are breached.

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Open the file Understanding Simulation Results.f3d

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in the Simulation workspace and then solve the study.

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Notice that there is an instantaneous change in the geometrys

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Notice that there is an instantaneous change in the geometry

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a sharp edge near where the load is being applied.

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This can cause a stress singularity, meaning that the stress in this area

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will be theoretically infinite, and the value presented in the results

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will continue to increase as the mesh is refined.

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To rectify this, it is useful to remove such instantaneous changes in geometry.

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For this, a fillet may be used in the Simplify workspace.

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From the Toolbar, select Finish Results.

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Then, click Simplify.

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Clone the simulation model.

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From the Browser, right-click Simulation Model 1,

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and, from the shortcut menu, select Clone Simulation Model.

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This opens the Clone Simulation dialog.

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From the list of studies, ensure Study 1 – Static Stress is selected and then click OK.

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The Browser updates with a duplicated simulation model called Simulation Model 2.

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With this model active, expand the Modify drop-down and select Fillet.

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The Fillet dialog displays.

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In the canvas, select the sharp edges of interest and drag the arrows to create the fillet.

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To make these fillets precise, in the Specify radius value input field, enter 3.

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Click OK.

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Then, in the Toolbar, select Finish Simplify.

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Save the file.

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Before viewing the results, the mesh must be regenerated.

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From the Browser, right-click Mesh and select Generate Mesh.

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A progress dialog displays, indicating the status of the meshing.

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Once it has finished, solve the study.

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In the Toolbar, Solve panel, select Solve.

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The Solve dialog displays.

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Click Solve.

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The Job Status dialog displays, indicating the progress of the solving job.

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When it is complete, the results display in the canvas.

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Save the file.

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Now the stress has been reduced to a much lower value.

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However, this stress is still above the yield strength of the material,

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which is 207MPa in the case of mild steel.

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Therefore, these results may still not be trusted.

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However, it may be certain that plastic deformation would be experienced by this component.