Objective: Impose Section Cut-level stiffness requirement and size the panels and beams corresponding to that section to meet the requirement.
In many cases, structural constraints will be given in terms of section properties at certain locations along the model using beam theory approximations. This is particularly useful when implementing aeroelastic or dynamic requirements into the static structural sizing realm. HyperX Section Cut entities allow the user to create section cuts at given locations of interest and implement stiffness requirements at each. These requirements are then imposed on the Zones that make up the cut plane during Sizing.
Creating a Section Cut involves selecting elements along a particular plane to define the section boundaries. This operation is initiated from the Structure tab of the Ribbon and can be completed in several different ways. See Section Cut Creation.
From the Section Cut definition window:
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Open the 'Constraints' pop-out, indicated by the first arrow.
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In many cases, it helps to have the current section properties shown in the Calculated Properties pop-out, to understand how new requirements compare.
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Fill desired fields with corresponding constraints and preferences. All of these fields are options to tune the optimization, but they are not all required.
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Min Stiffness: Fill empty fields with \(EI_{hh}\), \(EI_{vv}\), and/or GJ stiffness values, respectively.
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Zone Stiffness Distribution: Use the slider bar to choose what the HyperX stiffness optimization algorithm prioritizes during sizing. The far right represents a case in which all stiffness is added to the 1 or 2 Zones along the boundary that will most efficiently reach the requirement. At the left end of the spectrum, the stiffness is spread evenly among all Zones within the cut plane.
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Principal Angle Bounds: Fill the empty fields with a desired angle range for the principal axis angle to stay within during stiffness optimization.
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Location Bounds: Fill the empty fields with a 2D coordinate location range for the section Neutral Axis (CN) and the section Center of Gravity (CG), respectively, to stay within during stiffness optimization.
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Click 'Apply' to save these constraints to the Section Cut.
To ensure that HyperX assesses the stiffness of each Zone - and therefore enforces the stiffness requirement imposed on the section - a Stiffness Requirement Failure Mode must be assessed during Sizing. An example of this is shown below.
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You can select methods corresponding to whichever stiffness term is applicable - i.e. Membrane Stiffness when the section has an EI requirement, and so on.
This Failure Mode should then be added to the Analysis Property containing all other analysis methods the Zones should be Sized to.
Use the Legend to review the Sized Zones. A few tips to check that the stiffness constraints were applied appropriately:
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Plot the Controlling Criterion. This allows the users to quickly see which Zones were driven by the stiffness requirement.
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Use the Section Cut form to directly compare the updated calculated properties to the required value.