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Optimised 3D - Printed internal beam structure

News International-French

15 Feb 2019

3D-printed internal structure tailored to improve the static and dynamic properties of CFRP beams.


Optimised 3D-printed internal beam structure

Printed internal beam structure (Courtesy of CompoTech Plus SPOL, s r.o.)

Composite machine tool and automation frame structures are thin-walled filament-wound carbon laminates with axially-placed graphite fibres. Designed for a maximum bending stiffness and high natural frequency while maintaining a low weight, they suffer from wall instability under shear and buckling conditions. Limiting this instability by additional laminae leads to significantly increased structural weight. Internal carbon structures with a high-density foam support, for manufacturing and section shape, are also used. This is labour intensive and involves high processing time and cost. A better design solution is needed for more efficient and lightweight structures.

To solve this problem, a topology optimisation approach was adopted in order to develop the optimal distribution and cross-sections of a lattice-like internal beam structure. The optimisation output of non-uniformly distributed modular lattice elements was then automatically exported for production using additive manufacturing. The structures are currently 3D printed by layer deposition of ABS (acrylonitrile butadiene styrene). The final objective is to produce the internal 3D structure from continuous carbon fibres saturated with a thermoplastic epoxy resin.

The internal structure is primarily designed to improve the mechanical response to operational loads. It also has to withstand the production process. This internal structure provides a rigid connection with a steel mandrel that is removed after curing. This is important as the torsion and bending forces during the fibre laying process can affect the accuracy of the section tolerance and run out in the final precision-pressing stage. This can then reduce machining and cost. The internal structure is also designed to withstand a set of loads and stresses created during the compression moulding process within a set deflection requirement.

During the pressing step, the resin is cured before release from the press when post-curing occurs.

3D-printed internal structure tailored to improve the static and dynamic properties of CFRP beams.

Key Benefits:
> Improving the dynamic performance of machine structures
> Globally optimal least-weight design of the internal structure
> Limiting the wall instability of thin-walled layered composites
> Reducing the need for human interventions during design and fabrication
> Increased cost competitiveness

This 3D-printed internal structure has been selected as a finalist for the JEC Innovation Awards 2019 in the Aerospace category.

The JEC Innovation Awards - organized by the JEC Group - are recognized as the industry’s most prestigious awards that identify, promote and reward the most innovative composite projects worldwide. The award winners will be announced during JEC World 2019 on 13 March at 4.30pm. 

Compo Tech Plus SPOL, s r.o. will showcase their innovation at JEC World 2019 at Booth E57, Pavilion 6.Their associated partner is Czech Technical University in Prague.