Aerodynamic Design Process Consulting Services

Rapid Surfacing for Composites (Achieving Class A surfaces using Parametric Methods)

The Problem:

Composite materials are becoming more widespread in all sectors of engineering primarily due to their light weight and strength that can be tailored to specific needs.

The aerospace, energy and marine industries in particular require the aerodynamic and hydrodynamic performance not to be compromised. For example, an aircraft wing has to maintain a certain shape in flight to avoid drag penalties while a wind turbine blade has to extract energy from the air as efficiently as possible. Racing boat hulls and sails also have to perform well under challenging weather conditions.

These requirements and the attractiveness of composite material properties often means novel and advanced methods of construction. The CAD design tools such as CPD (Composites Part Design) in CATIA have been developed in response to this growing need for specific digital definition to facilitate the manufacturing process.

As such, they impose specific requirements on the mathematical definition of the surfaces to be manufactured. They must

  • possess smooth curvature variation
  • be curvature continuous across patches,
  • have few patches,
  • have correctly aligned isoparametric curves and
  • be of low degree.

These criteria apply equally to the Zone, Grid or Ply by Ply method as used in the CPD workbench. However, they can often impose undue constraints on the designer during the development stages when parametric methods are desirable to quickly explore the design space linking with CFD and FE in a multi-disciplinary approach. This often results in a manual design approach where the surface quality dictates the methodology used in the design process. The longer lead times means fewer design iterations and loosely coupled integration with other disciplines such as CFD, Stress and Production.


The Solution:

To this end, I have developed a surfacing framework in CATIA that serves both requirements well, delivering a robust parametric method for aerodynamic design and producing a fit for purpose geometry for manufacture.

The surfacing methodology can be applied in a bespoke manner to any project where aerodynamic/hydrodynamic characteristics are key to the performance of the component and manufacturing has to achieve the design intent to within a challenging tolerance.

The parametric definition can be developed to vary any geometric shape parameters Ð size, height, thickness, gradients, curvature, twist, camber, LE, TE while at the same time linked to a high quality surface output. In most cases the resulting surfaces have the desired quality for manufacture. However, in cases where this might not be the case the methodology sets up the surfaces for the final surface tweaking using dedicated Class A surfacing non-parametric tools. The resulting process therefore exploits parametric design capabilities while reflecting manufacturing constraints.


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