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Bamboo Reinforced bIocomposite with High mecHanical properTies

Final Report Summary - BRIGHT (Bamboo Reinforced bIocomposite with High mecHanical properTies)

Executive Summary:
BRIGHT was part of CLEAN SKY’s Research and Technology development projects. The Call for Proposal “Application of bio materials based on bamboo fibres to cabin interior composite sandwich panels” aimed at developing Technology Demonstration, at a Technology Readiness Level of 6, to enable bamboo to get closer to being used in aeronautic applications.

This project targeted to develop an appropriate bamboo fabric for aeronautical applications. Moreover, the process to extract bamboo and to transform it into fabric aims to be a low energy process. From bamboo fabric, another key challenge is to turn this fabric into composites (laminate and sandwich panels) suitable to be used for aircraft interiors. To valorise all the technologies developed within the project, a mid-cabin cabinet was to be manufactured and assembled.

First of all, with inputs from the Topic Manager, a specifications document gathering all informations required to lead this project and to give all objectives to reach (mechanical properties, fire requirements or sustainability...) was produced.
The first step was to select the most appropriate specie for aeronautical mid cabin applications. For that, auditions of bamboo cultivators were performed and a selection of several species answering requirements was done. Technologies to extract fibres from raw bamboo and to manufacture infinite wire, were optimized in terms of energy consumption and product quality. Weaving tests were also done using prototype infinite wires. A continuous process was analysed and established.
A product Life cycle Assessment enabled to clearly demonstrate that bamboo fabrics using such infinite wires had improved environmental impacts compared to standard glass fibre fabrics.
During the development of the bamboo fabric, studies to develop a bamboo composite matching the requirements were performed on a hand-made bamboo fabric. Protocols to improve impregnation between bamboo fabric and epoxy resin and to enhance fire-retardant properties of bamboo fabric were set. Mechanical and fire tests performed on bamboo composites (both laminate and sandwich panel) showed compliancy with specifications. A 3D model and FEM model of demonstrator were made but due to a lack of time, the demonstrator was not manufactured.

As a conclusion, BRIGHT has enabled to develop significant Technology Demonstration to answer most of the challenges but some tasks of interest remain unfinished and could be studied in the future as well as new topics of interest. These should include a methodology to get homogeneous, constant and reliable bamboo fibres (i.e batch to batch consistency regarding mechanical properties); an overall optimization of the process to get thinner bamboo infinite wires and fabrics (extraction step, weaving step...) and the development of a bamboo pre-preg.

Project Context and Objectives:
Natural fibers are rapidly emerging in composites applications where glass fibers have been traditionally used. These natural fibers provide several benefits: low cost, sustainable and abundant availability, lower densities, recyclability, biodegradability, competitive mechanical properties, and new functional characteristics.
Over the last decade, natural fibers have received increasing interest as a potential replacement for classical synthetic fibers and the Aeronautical sector is extremely interested by all these advantages.
Bamboo represents an interesting resource of fibers for composite applications thanks to four essential parameters: mechanical properties, availability, low density (average density of 0.9) and rapid growth. Bamboo fibers offer new perspectives for producing greener composites in the sense that they constitute a sustainable resource. In order to match with the needs of the aeronautical sector concerning mechanical characteristics of composites, Bamboo fibers have to be extracted and transformed into a continuous thread and then be braided into a fabric that could be treated and impregnated with specific resins.
The BRIGHT project will present an innovative low energy process for high quality bamboo fibers extraction, which conserves their intrinsic mechanical properties. The “infinite bamboo wire” resulting from this project will demonstrate its high performance for aeronautical composites applications. Moreover, BRIGHT’s composite process innovates in reducing the number of steps to produce sandwich panel composites.

The main objective of the BRIGHT project is to demonstrate the high mechanical properties of a bamboo fabric integrated in a sandwich panel as a green and efficient composite reinforcing textile meeting aeronautic constraints by:
-Developing a low energy process to transform bamboo into an appropriate fabric, preserving and optimizing the intrinsic mechanical properties of these exceptional bamboo fibers
-Demonstrating the high performances of a sandwich panel using our new composite in a mid-cabin demonstrator
This main ambition can be divided into five main steps which will make the overall BRIGHT project realistic, measurable and successful within a 16-month time frame:
1.Identify which bamboo species is the best candidate for producing an aeronautic bamboo fiber-reinforced composite for interior sandwich panels based on mechanical properties / availability / ethical considerations.
2. Optimize the patented process producing a high performance “infinite bamboo wire” with consideration of:
-Low environmental impact
-High conservation of bamboo specific mechanical properties meeting aeronautic specifications
3. Validate the fabric production and resin impregnation weaved with this infinite wire
4. Mould a composite using the bamboo fabric, previously developed, and characterize it in order to compare the results with glass fiber-reinforced composite performances and other natural fibre-reinforced composite performances
5. Manufacture a relevant “mid-cabin cabinet” part of the demonstrator using our bamboo sandwich panel composite.
Project Results:
For the validation of one bamboo specie suitable for aeronautical constraints and applications, some bamboo suppliers were audited with respect to sustainable development and culture maturity criteria. The results show great potential with some significant issues to be resolved. These suppliers would enable significant improvements in terms of products’ Life Cycle, as the distances between the bamboo plantations and production facilities would be optimized for a European manufacturer. Four species were supplied and infinite wires were characterized in terms of ultimate tensile strengths. These results were compared with 5 other selected species from background data. The most appropriate specie was therefore selected for aeronautical mid-cabin cabinet applications.
Future research on species could reasonably be extended as there is over 1500 species.
In order to have constant quality of extracted bamboo fibres, it is important to have a control on the way that bamboos grow. For that and similarly to what is currently developed for flax (CELC), it is important to support (by an agro-industrial organization) ongoing developments in the different Bamboo industries. Several actions are necessary to improve state-of-the-art on the following subjects:
- Impact of soil geochemistry of use area as a function of selected bamboo specie.
- Impact of culm maturity on properties of bamboo fibres
- A methodology on variability of properties of bamboo fabric with a tolerance as a function of field of application to ensure a final Object meeting the requirements

For the development of a bamboo fabric, thorough analyses and optimizations were performed on the main modules of fibre extraction, fibre assembly and wire winding.
Results enabled to produce prototype infinite wire with optimized fibres. The assessment of the fibre extraction facility concluded on the need to redesign it in order to increase fibre quality and productivity of strips, as well as to match the requirements (width, thickness,...).
Fibre assembly experimentations provided data and the limitations for different types of patented assembling technologies. Analyses also showed the constraints of the assembling technology in terms of energy consumption and time-lapse for multiple bobbin manufacturing.
Wire winding tests brought out conclusions on the type of winding required for appropriate weaving.

The produced BRIGHT prototype infinite wires were analysed and tested by weavers to manufacture several types of fabrics such as weaved, multi-axial and unidirectional. Several limitations were identified which opened doors to new tests. For all types of fabrics, there is a good level of confidence to achieve fabric production in the close future. However, further testing still has to be performed in order to produce industrial BRIGHT bamboo fabrics, hence in large quantities to manufacture the demonstrator.

Analyses and developments were performed on the overall process in order to enable continuous manufacturing. An evolution of procedures enabled such a production. However, this continuous process and the weaving step should be further optimized to allow the production of infinite wire and bamboo fabric suitable for aeronautical application.

Products’ Life Cycle Assessments considered 16 indicators such as ozone depletion, human toxicity...The study came to the conclusion that for BRIGHT’s bamboo fabric, the most impacting variable was packaging with over 50% environmental impact on 44% indicators. Transport was the second main contributor. Relevant solutions were put forward to improve the overall environmental impact, such as the use of recycled or renewable materials for packaging instead of plastic based products. Nevertheless, 15 indicators showed a significant improvement compared to a standard glass fibre fabric. Only the Land use indicator was slightly increased (1%).

A focus was made on energy consumption for both the bamboo based fabric and a glass fibre fabric.
The analyses, excluding packaging for better understanding of manufacturing processes, showed that BRIGHT’s bamboo fabric required 50% less energy consumption for its production compared with the glass fibre production even though capabilities are very different as glass is produced in enormous amounts. The explanation comes from the fact that glass fibre requires high temperatures to be produced.

The Life Cycle Assessment and the energy consumption studies were only performed up to the fabric due to lack of data, but this study should be completed to a composite level to have an overall view of savings.

During the development of BRIGHT bamboo fabric, a fine analysis of state-of-the-art regarding treatments already presented in the literature to improve impregnation and fire-retardancy of natural fibres was done. From this research, several treatments were tried on a commercial bamboo fabric as well as combination of treatments to improve adhesion between bamboo fabric and the matrix. To define the best treatments, several analyses were performed on bamboo (microscopy, surface tension). The treatments were also looking through the environmental impact in terms of toxicity, recycling and energy consumption.
Sourcing of resins was done and appropriate ones, i.e. resins that can be used in aeronautical environments and in line with requirements were supplied. All resins were analysed. Criterion of environmental impact was also taken into account to choose the resin.
Impregnation testing were performed in order to improve adhesion between fabric and matrix, surface aspect and to reduce porosity. Several processes like pre-pregs, vacuum bag moulding and resin film infusion were considered. Because of time and budget considerations, only some of them were tested and one process was approved. In the future, it would be interesting to study the development of pre-pregs of bamboo fabric since it is one of the processes widely used in aeronautical industry. The development and the use of fire-retardant bio-resin should also be interesting to study.

To meet the requirements for aeronautical applications, composites should meet the standards for fire and mechanical tests.
Consequent works were performed to improve fire-resistance of bamboo fibres. Indeed, natural fibres are more sensitive to fire than other fibres such as glass fibres. Several treatments were tested. Some of them promoted char formation that protect fabric from further burning. An optimal formulation was found and tested successfully. Indeed, several bamboo laminates and panels met the fire requirements.
Bamboo panels and laminates were realized in order to characterize them.
A mechanical study was also conducted on laminates and panels and it was shown that bamboo fabric chosen was suitable for aeronautical cabin interiors applications. Equivalent or better mechanical properties were obtained with bamboo panels compared to standard glass fibre panels used in aeronautics with the same panel weight.
Therefore, a protocol to produce bamboo-based composite panel was successfully set up. This bamboo sandwich panel exhibits remarkable properties that match the requirements for cabin interior environment. This panel provides an alternative solution to glass fibre sandwich panel. These technologies were not implemented onto BRIGHT’s bamboo fabric since the project ended before the manufacturing of sufficient amounts of BRIGHT bamboo fabric. Future work would implement the technologies developed here to enhance impregnation and fire-retardant properties on bamboo fabric suitable for aeronautic mid-cabin applications. So, the demonstrator could be manufactured.

However, regarding the demonstrator, a complete 3D, FEM models and all manufacturing drawings of the mid-cabin cabinet were made. Finish materials were approved and panels’ panoplies were designed for CNC programming. Moreover, several tests on bamboo panels showed that bamboo panels can be used for aircrafts interiors furniture. Indeed, cutting process of bamboo panels with CNC (computer numeric control), edge filler application, pockets machining and assembling process with inserts were validated.

Potential Impact:
The impact of this project will be significant when commercialization of bamboo fabric and bamboo-based composite will take off. So far, the overall progress was made on single technologies (either on bamboo fibre/strip, infinite wire or bamboo fabric) and not fully implemented into a demonstrator. Bamboo farming will also be developed but an effort has to be made on the development of bamboo industry to have reliable and consistent quality product especially for aeronautical usage. This effort has to be made at several levels starting from bamboo growth, its manufacturing into fabric up to the composite products. When the previous conditions will be met, BRIGHT project will enable to accelerate the development of the companies that took part in it, regarding employment for example.

The main dissemination activities of this project were interviews by local press (paper, TV), publications on company website or publication in specialized press (composite).

The study on bamboo species and the selection of bamboo species that fulfil technical requirements can be exploited to develop wires and fabrics from these species. Some further testing is however still required as there is a significant number of species available on earth.
The outputs of the study on fibre extraction tool, fibre assembly, multiple simultaneous fibre assembly and bobbin winding will be exploited and will help to redesign and finalized the production line of bamboo infinite wire.
The results of energy consumption for the production of bamboo fabrics using technologies used and studied during BRIGHT show a positive impact that will be beneficial for dissemination.
Life Cycle Analysis (LCA) of bamboo fabric have identified the key parameters (packaging) that impact results. Proposed solutions will therefore enable to decrease the impact of future products.
Study of improvement of impregnation and fire-retardancy of bamboo fabric led to satisfactory results and exploitation of these results will lead to a patent of the protocols developed during BRIGHT project. Further work would include the use of these protocols on optimized bamboo fabrics for the production of a demonstrator. Future interesting works could also include the study of bamboo composites implementation with process close to those used in aeronautics, such as pre-pregs.

List of Websites:
67 rue de la Colombette
31000 Toulouse

+33 6 75 66 50 17

VESO concept (Coordinator)
1620 route de Bellevue
31530 Mérenvielle
For further information, contact:
Mr David HARDY (CEO VESO-concept)
+33 534 575 490

Kreative Engineering Services (KES)
11 Faubourg Bourbon
For further information, you can contact us at: