You are here: Home | Technology


The expertise of CoDeT can handle three increasing levels of complexity. The fibre orientations of each individual ply in a regular straight fibre Constant Stiffness (CS) laminate can be optimised for structural objective functions such as strength, stiffness, buckling load, fundamental frequency and aeroelastic response. More advanced blended laminates (F1) can also be designed in which the fibre orientations and thickness in each region of a component are optimised for structural objective, whilst ensuring the stacking sequence compatibility on their interface zones.

In the most advanced form, laminates with curved or Steered Fibres - and thus Variable Stiffness (VS) can be created. A unique advanced optimisation formulation is applied where the theoretically ideal stiffness distribution in the laminate is first found which ensures the optimal global load paths. Then a Steered Fibre path lay-out (F2) is found for each fibre in each ply, which approximates the optimal stiffness distribution as well as possible within practical Automated Fibre Placement constraints. The result is an optimal laminate, found from millions of laminate candidates.

The benefit of VS laminates with respect to conventional and blended laminates is that a higher structural performance can be obtained with the same weight, or alternatively weight can be saved for the same performance. For example, the buckling load of a square Steered Fibre panel (F3) for instance was increased 40% with respect to the tailored conventional (CS) laminate and the material failure load (strength) of a rectangular Steered Fibre panel with large cut-outs (F4) increases 30% with respect to the conventional (CS) laminate.

The natural frequency of components and assembly can be optimised through tailoring the stiffness distribution with VS technology application. This may reduce noise in the sense of reduced vibration creation and transmission. For example, a frequency gain of 31% was achieved for a rectangular plate.

Tailoring of Morphing Structures

Morphing structures can be employed as an alternative to conventional mechanical control surfaces. The leading edge and trailing edge of a wing for instance can be morphed to replace slats and flaps/ailerons (F5). Alternatively, local zones of conventional structures like the trailing edge of a slat can be designed as morphing (F6). The benefit of these structures is that the gaps in the effective airfoil can be eliminated or adjusted, which reduces airframe noise.

Variable Stiffness composites are ideally suited for morphing structures. The ability to vary the fibre angle as well as the laminate thickness (F7) provides elastic tailoring capacity for achieving the optimal compromise between required activation deformation and sufficient aerodynamic load-carrying capacity of the device. This is done by optimising the stiffness of the structure to achieve target geometry under specified actuator and aerodynamic loading, whilst imposing strength constraints.

CoDeT is already gaining expertise in morphing structure through the involvement in the MOSKIN project, where a morphing leading edge is designed, built and tested as replacement of a conventional wing slat.


F1 - Blended laminate

F2 - Steered Fibre laminate

F3 - Produced square VS Laminate

F4 - Produced rectangular VS Laminate with large cut-outs

F5 - Static and deformed (blue) shape of a morhping wing

F6 - A morphing part of a slat for adjustable air gap

F7 - Steered Fibre and thickness tailoring of a leading edge


Login Form