When do you use HyperX Software?

Conceptual Design

In the early phase of aircraft design, engineers are typically focused on speed and exploring the design space. Design to loads are entered either directly with table entry, or by using smeared coarsely meshed GFEMs. In either case, quick trade studies are performed to make decisions on material systems [thermoset/thermoplastic/resign infusion] and architectural layouts [such as wing rib and fuselage frames spacings]. Other design decisions to be made include panel concepts such as Sandwich vs Tee or Hat Stiffened.

During concept definition loads cycling occurs frequently with FEM updates and resulting FEA computed forces. As the structural members are being changed, the internal static load path is redistributed and converged.

In the conceptual phase there are billions of practical and relevant structural design alternatives to process. Even high performance computing (HPC) with multithreading and multiprocessing cannot evaluate all of these candidates. Needed is a way to funnel down options that enable the engineer to interactively steer the sizing optimization, fully benefiting from his experience and intuition with power of computation.

The HyperX capabilities listed to the right provide solutions to these needs.

Preliminary Design

In preliminary design, leading up to Preliminary Design Review (PDR), the vehicle is well-defined. The FEA has 1000’s of load cases to represent the complete flight envelope and off nominal events. Loads groups and structural analysts are working together to converge internal load paths and to meet required airframe stiffnesses. In the case of a wing, these are EI and GJ cut section values per station.

Part cross-sections and layups are being selected. Laminate ply drop ramp rates such as 20 to 1 are being met.

Line loads are used to begin evaluating joint concepts.

FEA eigenvalues are computed to predict buckling.

The vehicle is represented with a ‘loads’ model, referred to as a GFEM (Global) or as a AVFEM (Air Vehicle).

Critical Design

Critical design marks the shift to a mature structure design with most decisions made on manufacturing tooling, panel cross sectional dimensions, and acreage layups are locked down. Since most of the design has been chosen, higher-fidelity models contain more elements to discretely model features such as stiffeners, fasteners, sandwich core ramps, and metal fittings. Final material allowables are established for strength checks, including damage and fatigue criteria.

This phase typically has aerospace engineers working to resolve negative margins of safety to final FEA load iterations in order to submit passing designs for Critical Design Review (CDR).

A need is in depth analysis traceability.

At this stage the vehicle is represented with a DFEM (Detailed) model with a finer mesh that discretely models features.

Solid elements are used for fatigue analysis of fittings. Lugs are typically analyzed using classical aerospace methods.

Part Release

The aircraft design cycle ends with part release. In order for parts to be released to the shop floor, they must be fully defined in part drawings, with all manufacturing considerations considered. These drawings are typically accompanied by detailed stress reports, which contain summaries of all design and analysis requirements, margin reports and screenshots of important part data.

At this phase iterations are done between stress sizing and results produced by AFP software such as CGTech’s Vericut. Margins are defined that account for simulating fiber paths of complex curved parts that quantify steering radius limits and laps and gaps in slit tape placement and corresponding updates to the FEM ply rosette angles.