Structural Analysis and Optimization
HyperSizer® is stress analysis & sizing weight reduction optimization software for structures
Very rapidly perform complete vehicle failure analysis and structural sizing optimization with different panel concepts, material systems, and layups. Report and store results of many trade studies.
Panel and Beam Stiffness Software Tab »
Computed Properties Tab»
An extensive “breadth-and-depth” design space exploration can be performed in a Progressive Design funneling process performed in stages to target an optimum design. Innovative “back to the drawing board” concepts can be proposed, evaluated, and filtered out for the next stage of the design maturation process. The complete airframe including fuselage, tanks, wings and most of the engine including inlet, nozzle, combustor, and nacelle can be analyzed and optimized using several different panel and beam concepts and material systems. Panel concepts such as uniaxial Tee, blade, I, Zee, and hat stiffened; orthogrid concepts such as orthogrid, bigrid, isogrid; and sandwich concepts such foam and honeycomb can be included, as well as many materials such polymer composite graphite/epoxy, graphite/polyimide; ceramic composite C/Sic; and advanced metallic alloys such as Gamma Ti/Al.
How? HyperSizer couples automatically to FEA such as NASTRAN for system level trade studies, local sizing optimization, and structural component failure analysis margin-of-safety reporting, while reducing engineering time and effort. As a productivity and standardization tool, the software saves time and documents results during the conceptual layout phase all the way to generating the final design stress reports. By fully exploring the design space, in most cases HyperSizer is able to reduce airframe weight 20%.
Iterative Coupling Between the FEA Loads Model and HyperSizer Structural Sizing
Once optimum internal substructure layouts for wing spar, rib, and fuselage ringframes are defined based on panel span length optimization trades (optionally using the HyperSizer Object Model), a finite element model was built and external flight loadings applied such as surface pressures, inertia, and landing forces.
Resulting FEA computed internal loads are retrieved and input automatically for analysis and sizing of the panels and beams. At this point HyperSizer performs hundreds of analyses such as advanced composite failure, cross section crippling, buckling stability, and bolted & bonded joint analyses. Each panel concept has unique failure analyses to perform. For a honeycomb sandwich, these include core crushing and crimping, and facesheet wrinking and dimpling. If any analyses has a negative margin-of-safety (-MS) as indicated in the figure below with red text, then the sizing optimizer will determine the lightest combination of all design variables and material selections which achieve positive margins for all failure modes, for all loadcases, and for all locations and components of the structure.
HyperSizer then creates generalized thermoelastic stiffness terms to send back to the FEM for another iteration of computed internal load paths. HyperFEA™ controls this iterative convergence.
HyperSizer Detail Analyses to FEA Computed Internal Loads
General failure analyses that apply to any panel concept include panel buckling and material strength. In this example the facesheet material is Aluminum, so the isotropic stress checks are in the principal longitudinal, transverse, and shear directions, as well as the Von Mises interaction yield criterion. Margins-of-safety (MS) are reported for limit loads with yield material stress allowables, and for ultimate loads with ultimate stress allowables.
Sandwich specific failure analyses are performed for the honeycomb core material. These include crushing of the core from concentrated loads, from flexural bending, and from joint supports. Additional core failure analyses are crimping, and shear strength in the longitudinal or transverse directions. For the sandwich facesheets, the relevant failure analyses to check are wrinkling and intracell dimpling. The stress analyses can include co-bonded or co-curred correction factors for the laminate strain allowables, and also corrections to account for honeycomb cell size. These types of test data correlations are available and required as a design progresses to certification.
On the shown HyperSizer Failure Tab, the user can click the mouse cursor in each individual cell to toggle a particular failure analysis on or off. If on, HyperSizer will report a margin. If the margin is positive, the font is black. If negative, a red font is used to flag the user’s attention. The words “Very High” in the cell indicates that the MS is over a 100, as in this example for core crushing from flexural bending loads. Also for this example, the analyses for stiffness requirements, and strain and frequency limits have not been toggled on, so the respective cells do not have reported margins.
Global-Local-Detail modeling
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Global to local to loading effects are captured with FEMs of increasing mesh refinement. However, even the finely meshed FEMs do not have to include the stiffener shapes or spacings in order for HyperSizer to capture detail stresses.
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These coarsely meshed loads FEMs are all that is needed for HyperSizer to quantify even details such as computing interlaminar shear and peel stress variation in the last ply in contact with a stepped bonded joint Global-Local-Detail»
A Progressive Analysis» process for including more computationally demanding analysis solutions is also provided. For instance, starting with damage initiation of a bonded stiffener, HyperSizer can track the progression of laminate delamination failure ending with the resulting residual strength at limit loads.
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An FEM and FEA post processor
Interaction between the engineer and the software is key to HyperSizer's design process. Interactive graphics provide visual inspection of the drawn-to scale optimum panel and beam cross sections. In this example an isogrid stiffening pattern is displayed. These features are used to identify and correct design flaws early. Integrated with the local graphics of panel cross sectional details are HyperSizer graphics software for displaying the FEA internal loads and modifying the FEM, FEM graphics»
Structural Analysis Links
There are many customer examples that highlight different uses and capabilities of the software. These examples are available at Project Briefs»
A foundational capability of HyperSizer is the approach for formulating the temperature dependent, structural stiffness of any stiffened panel cross sectional shape very accurately. This allows it to calculate very detailed stresses and strains, through the depth of a panel including its laminates, without the need of constructing extremely high element FEMs. This thermoelastic formulation process was introduced in the Global-Local-Detail» page.
A second foundational capability is the hundreds of failure analysis methods provided in HyperSizer. A summary of some of those, and the appropriate design phase to include the more computationally demanding analysis solutions are described in the Progressive Analysis» process. For instance, starting with damage initiation of a bonded stiffener, HyperSizer can track the progression of laminate delamination failure ending with the resulting residual strength at limit loads.
Complete documentation of HyperSizer methods and equations is made available to customers at this link: Analysis Methods and Equations (Customer Login Required)»
Recently published papers on HyperSizer analysis methods are provided at our downloads page. Before going there, another location for publicly released composite analysis methods is this link: Advanced Composite Analysis Topics»
Click here for a Technical Summary»
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