Create and solve a convex hull calculation

In this example, you use a convex hull method to create and solve load case filtering calculations to filter the most significant pressure loads on the stringers and ribs of wing. The load case sets used in this example include only combined load cases. All other load cases are excluded from the load case filtering calculation.

Note:

This example assumes that you created a load case filtering solution process, created a load case set from the available combined load cases in the solution, and added the load case set to the solution.

To create the calculation, you use the Force vs Moment (2D Convex Hull) method and extract results from 1D elements along polygon edges that make up the stringers and ribs on the top portion of the wing.

1. Choose Load Case Filtering tab→Solution group→Filtering Calculation .

2. Next to Method, click Select a method .

3. In the Calculation - Method Selection dialog box, from the Method list, select Force vs Moment (2D Convex Hull) and click OK.

4. On the Inputs tab, next to Load 1 (l1), click Edit Load Extraction .

5. In the Load Extraction dialog box, Selection group, do the following:From the Type list, select Polygon Edge.In the graphics window, select all of the (1) polygon edges that make up a stringer.Tip: To ensure that you select the geometry, in the Simulation Navigator, deselect the 1D Collectors and 2D Collectors check boxes to hide all meshes.Click Confirm source edit .The source appears in the Sources table

6. In the Result group, do the following:From the Result Type list, select Beam Resultants - Element-Nodal.From the Component list, select Axial Force NXX.From the Combine At list, select Elements.

7. Click OK.

8. Next to Load 2 (l2), click Edit Load Extraction .The Load Extraction dialog box opens. The polygon edges that you selected for the source in step 5 are still selected in the Sources table.

9. In the Result group, do the following:From the Result Type list, select Beam Resultants - Element-Nodal.From the Component list, select Bending Moment MYY.From the Combine At list, select Elements.

10. Click OK.

11. In the Tolerance (tol) box, type .05 and click OK.Specifying a tolerance value of .10 or less is considered a best practice. After you specify a tolerance, you can solve the calculation to determine how many load cases are selected. You can then adjust the tolerance based on the number of load cases. For example, if you find that the software selects too many load cases, you can lower the tolerance value and re-solve the calculation.An annotation appears in the graphics window, pointing to the stringer from which the calculation is extracting results.

12. In the Simulation Navigator, expand the Calculations node, right-click Force vs Moment (2D Convex Hull) and choose Rename. Type Stringer1 and press Enter.Renaming the calculation lets you keep track of the calculation for each stringer in the solution.

13. Repeat steps 1–12 to create an additional calculation and rename it for the next stringer.Repeat this step for as many calculations as necessary. This example has 8 stringers and 10 ribs, so you need 18 load case filtering calculations if you want to consider all of the loads for each of these structures.

14. In the Simulation Navigator, right-click the Calculations node and choose Solve All Calculations.

15. Close the Information window.

16. In the Simulation Navigator, right-click the Load Case Filtering solution node and choose Display Results.

17. In the Load Case Filtering Results dialog box, in the Load Case distribution group, sort the results using the Frequency column.The Load Case distribution group displays the frequency with which each load case is filtered in all calculations.

18. Select the load case with the highest frequency, press and hold Ctrl, and select the load case with the second-highest frequency. Right-click the selection and choose Create Load Case Set.The Load Case Set Editor dialog box opens with the selected members of the new load case set.

19. Click OK and click Close.

How do I

Create a load case filtering calculation

Learn more

Load case filtering calculations

Parent/child behavior in load case filtering calculations

Extracting a single value from the set of results (load case filtering)

Sources manager (load case filtering)

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Create and solve a convex hull calculation, Simcenter 3D 2021.1 Series

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