HiPerDiF (high performance discontinuous fibre) technology, invented at the University of Bristol, produces highly aligned discontinuous fibre composites with the goal of addressing the issues of the composite industry - manufacturing and recycling.

HiPerDiF capabilities

The high-volume, automated process of producing defect-free aligned discontinuous fibre composites via HiPerDiF will lead to a significant advancement in the sustainability of composite materials.

Fibre alignment

HiPerDiF technology employs a series of fibre-water jets aimed perpendicular at an array of slotted plates.

Each fibre-water jet has a corresponding plate. The momentum change of the fibre-water jet on the plates aligns the fibres, parrallel to the plates.

The fibres are deposit on the mesh conveyor belt and water is removed via a vacuum pump.

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Drying stage

The use of water as a dispersing agent leads to easy removal of water from both synthetic fibres and natural fibres  using a combination of vacuum and IR heating. 

 

Preform fabrication

A combination of preforms can be fabricated using a diverse range of fibres; natural, synthetic (virgin and reclaimed), along with thermosetting and thermoplastic matrices

 

Comparison to long fibres: Aligned discontinuous fibre composites with 85% of the fibres aligned within ±5⁰ from perfect alignment led to comparable properties to continuous fibre composites, using HiPerDiF [1]. 

                                 Figure 1. Mechanical properties of ADFRC from HiPerDiF [1]

Pseudo-ductility: Hybrid composites (intermingled [2], intraply [3] and interlaminated [4][5]) achieved pseudo-ductility through fragmentation and diffuse debonding/delamination.‌

                                 Fig. 3. Intraply hybrids [3]

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                                 Fig. 4. Interlaminated hybrids [4][5]
 
The high mechanical performance and pseudo-ductility achievable with the ADRCS manufactured with the HiPerDiF technology are also retained when laid-up in a quasi-isotropic sequence [6]. Furthermore, it is also possible to achieve pseudo-ductility by exploiting the pull-out mechanisms by changing the nature of the matrix, e.g. from epoxy to polypropylene [7].

Recycling & Sustainability: Composite recycling is a two-step process: the degradation of the matrix to reclaim the fibres and their remanufacturing in a new recycled material. Independently from the matrix degradation processes the reclaimed fibres are in a filamentised, random, low-density-packing form. The HiPerDiF technology allows to remanufacture them into high fibre volume fraction recycled composites with outstanding mechanical performance [8],[9],[10],[11] & [12].

 

 

Fig. 5. Life-cycle of fibre composites with HiPerDiF

 

Moreover the technology allow the processing of natural fibres to obtain sustainable composites [13].

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HiPerDiF can process natural fibres. Intermingled flax and re-claimed fibre (rCF) composites demonstrated damping and a cost reduction compared to a pure carbon fibre composite.

It is possible with HiPerDiF to vary the quantities of each fibre type and the type of hybrisation (i.e. intermingled, interlaminated etc.), allowing the design engineers to tailor the mechanical, functional properties and the cost.

 

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Benefits in Manufacturing: Discontinuous fibres reduce stress concentrations in features such as ply drops or help the pre-preg conform to small radii for AFP/ATL

 

 
 
 
 
3D Printing: Highly aligned discontinuous fibres feedstock from HiPerDiF can be employed in a 3D printer, providing all the benefits from the HiPerDiF technology

 
 
 
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Support from:

 

Further information: https://stl-tech.co.uk/hiperdif

The HiPerDiF technology was invented during the EPSRC funded HiPerDuCT programme.

This research was funded by the UK Engineering and Physical Sciences Research Council (EPSRC) the EPSRC “High Performance Discontinuous Fibre Composites—A sustainable route to the next generation of composites” grant number [EP/P027393/].