The help system contains resources describing the supported element types, solution procedures, etc. for using FEA models in HyperX. This page is designed to serve as a quick reference guide for the best practices of FEA modeling. Although not exhaustive, this guide is a self-contained reference for most of the modeling techniques relevant to HyperX.
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SHELLS: prefer CQUAD4 and CTRIA3. Also support CSHEAR.
Note
As of Version 2024.2, released in October 2024, HyperX also supports: CTRIA6, CTRIAR, CQUAD8, CQUADR.
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BARS: CBAR or CROD.
Note
As of Version 2024.2, released in October 2024, HyperX also supports: CBEAM.
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BOLTS: Only supported are CBUSH elements, used for fastener analysis.
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SHELLS: PCOMP, PCOMPG, and PSHELL are imported if desired.
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Use MAT8 cards for orthotropics, and MAT1 cards for isotropics.
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HyperX can import laminates and isotropic thicknesses with these combinations.
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BARS: Prefer PBARL, which allows HyperX to import dimensions. Also support PBAR, PROD for ROD elements.
Note
As of Version 2024.2, released in October 2024, HyperX also supports: PBEAM, PBEAML
HyperX does not support tapered beams - it will only look at the first station defined (end A of the beam). FEM update of the tapered beam will remove the taper.
An additional note on PBEAML support...
In the workflow involving Importing Properties and Materials to write margins to an as-modeled design, there are limitations to the PBEAML cross-sections supported for import. See table below.
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Nonstructural mass (NSM) is imported from the FEM for shell properties and included in weight summaries and exported upon FEM update unchanged.
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NSM is used to simulate the mass of a smeared-stiffened panel, which is exported as a PSHELL referencing MAT2 cards.
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If HyperX does not “support” a FEM entity (such as coupling interactions, rigid attachments, higher-order elements, etc.), the model may still be used within HyperX without issue.
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HyperX will only import entities it understands (shells, beams, etc.), and ignore all others.
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If a FEM update is executed with HyperX, all original FEM data that was not used by HyperX is copied over in its original state.
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SHELLS: HyperX relies heavily on material orientations. These can be modified in HyperX, but it is strongly recommended to be set in the preprocessor.
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Material orientations determine the fiber direction for composites, and the stiffener direction for stiffened panels
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Normal directions are also important. Element normals are assumed to point out of the aeroshell (in the opposite direction of the stiffeners for stiffened panels).
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Normal directions also indicate the direction of stacking for laminates.
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BARS: HyperX bar orientations must be set consistently throughout the model according to the HyperX convention.
Note
See Shell Orientation, and Bar Element Orientation for more information.
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SHELLS: Shell offsets (if applied) are automatically imported and used for sizing and analysis when transforming and localizing loads.
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BARS: Bar offsets are not imported from the FEM but will be automatically computed and exported during the FEM update process.
Note
See Shell Offsets and Bar Element Offsets for more information.
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When establishing mesh connectivity (such as the connection of a spar to a skin), ensure that spar and skin elements share nodes at the connection point.
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HyperX needs mesh connectivity to identify lines on which to split Zones if using the automated utilities to do so (such as splitting a large panel along a rib to allow for independent Sizing of the two new Zones).
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HyperX also needs to know mesh connectivity to associate stiffeners with skin sections for discretely stiffened models in order to accurately perform Panel Segment analysis.
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Use of RBEs for load introduction is acceptable, but often results in artificial load peaking. HyperX can use statistical load processing to reduce or eliminate the impact on sizing results, but ideally load introduction should be realistic for best outcomes.
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Whenever possible, material IDs should be used consistently throughout FEMs and HyperX. HyperX relies on material IDs to match materials between the FEM files and Sizing / Analysis Materials.
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This is necessary because HyperX requires much more information than is typically stored in MAT cards, such as laminate allowables, thermal properties, Correction Factors, etc.
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HyperX supports many common Nastran solution sequences:
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101 – Linear Static
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105 – Eigenvalue Buckling
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106 – Nonlinear Static
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112 – Modal Transient Response
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400 – Implicit Nonlinear Static and Dynamic
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HyperX only requires element forces as an FEA output when performing strength and closed-form stability sizing.
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Grid displacements, eigenvalues and modeshapes (for SOL105 or 112), may also be imported and used for deflection limits, sizing to FEA buckling results, respectively.
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Whenever feasible, subcases should be generated to isolate load combinations that would be superimposed.
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Example: fuselage pressure and wing up-gust should be included as two distinct subcases, not combined.
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HyperX will superimpose the loads as required internally, which may dramatically reduce runtimes for large numbers of subcases.
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Thermal cases should be run separately from mechanical cases, again to allow superposition.
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HyperX will also allow cases to be “flagged” as thermal and use help / hurt factors when combining with mechanical cases, if desired.
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Caveat: this strategy is invalid for nonlinear geometry or material properties. If using nonlinear FEA, combinations must be made before bringing into HyperX for accurate results.
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It is recommended to apply pressures directly on the FEM (using PLOAD cards), rather than using nodal forces, etc.
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For curved plates, it is common practice to use FEA to compute membrane, bending, and transverse shear loads due to pressure.
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For flat plates, it is desirable to compute the resulting moments and transverse shear loads due to pressure in a secondary step, as linear FEA is highly inaccurate for this.
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In HyperX, use the “Zero Curvature” option (prev. "Zero FEA Moments") to ignore the bending moments FEA computed due to pressure, and enable the panel pressure analysis to compute these offline. See Zone Settings for more information.
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HyperX needs to have the PLOAD cards in the FEM to determine what pressure to apply to components.
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