From the Sector

At this year's JEC World, STFI will be presenting highlights from carbon fibre recycling as well as a new approach to hemp-based bast fibres, which have promising properties as reinforcement in lightweight construction.

Green Snowboard
At JEC World in Paris from 5 to 7 March 2024, STFI will be showcasing a snowboard from silbaerg GmbH with a patented anisotropic coupling effect made from hemp and recycled carbon fibres with bio-based epoxy resin. In addition to silbaerg and STFI, the partners Circular Saxony - the innovation cluster for the circular economy, FUSE Composite and bto-epoxy GmbH were also involved in the development of the board. The green snowboard was honoured with the JEC Innovation Award 2024 in the “Sport, Leisure and Recreation” category.

VliesComp
The aim of the industrial partners Tenowo GmbH (Hof), Siemens AG (Erlangen), Invent GmbH (Braunschweig) and STFI united in the VliesComp project is to bring recycled materials back onto the market in various lightweight construction solutions. The application fields "Innovative e-machine concepts for the energy transition" and "Innovative e-machine concepts for e-mobility" were considered as examples. On display at JEC World in Paris will be a lightweight end shield for electric motors made from hybrid nonwovens - a mixture of thermoplastic fibre components and recycled reinforcing fibres - as well as nonwovens with 100% recycled reinforcing fibres. The end shield was ultimately manufactured with a 100% recycled fibre content. The tests showed that, compared to the variant made from primary carbon fibres using the RTM process, a 14% reduction in CO₂ equivalent is possible with the same performance. The calculation for the use of the prepreg process using a bio-resin system shows a potential for reducing the CO₂ equivalent by almost 70 %.

Bast fibre reinforcement
To increase stability in the plant stem, bast fibres form in the bark area, which support the stem but, in contrast to the rigid wood, are very flexible and allow slender, tall plants to move in the wind without breaking.A new process extracts the bast bark from hemp by peeling.The resulting characteristic values, such as tensile modulus of elasticity, breaking strength and elongation, are very promising in comparison with the continuous rovings made of flax available on the market.The material could be used as reinforcement in lightweight construction.At JEC World, STFI will be exhibiting reinforcing bars that have been processed into a knitted fabric using a pultrusion process based on bio-based reinforcing fibres made from hemp bast for mineral matrices.

Twelve companies from eight different countries will receive a JEC Innovation Award at JEC Asia 2018. Asia-Pacific is an innovative region that sets the tone for all other regions of the globe. Once again, the JEC Innovation Awards highlight how composites bring solutions considering the new challenges in terms of efficiency, sustainability and life-cycle analysis.

This year, JEC Group awards innovations in the following categories: aerospace (structural and tooling), automotive, commercial vehicles, e-mobility, marine, railway, sports & leisure, infrastructure & civil engineering, industrial equipment, sustainability and additive manufacturing.

The ceremony will take place on Thursday November 15, 2018 at the COEX Center of Seoul (South Korea). Ida DAUSSY (Seo Hye-na), will host the ceremony in front of officials, manufacturers, scientists and composites professionals.

Category: AEROSPACE – STRUCTURAL
Winner: CSIR National Aerospace Laboratories (India)

Most of the composite structures for aircraft are made of carbon-epoxy composites, which can withstand a maximum service temperature of 130°C. As a consequence, carbon-epoxy materials cannot be used in hot zones like engine vicinity areas. The Aeronautical Development Agency (ADA) and CSIR-NAL took up the challenge of developing high temperature resistant composites for use in hot zones of light combat aircraft, which would result in significant weight and cost savings, as well as a considerable reduction in the meantime between failures (MTBF) due to thermal ageing.

The first task was to choose a material system with a service temperature of about ~ 200°C. During the material selection process, it was found that BMI resins are a relatively young class of thermosetting polymers. Hence, a carbon-BMI prepreg was selected due to a number of unique features including excellent physical property retention at elevated temperatures and in wet environments.

It was realized that weight savings and performance can be maximized using co-curing technology. This results in a large reduction of fabrication cycle times, costs and weight. Co-cured structures have fewer fasteners, which results in shorter assembly cycle times and also reduces sealing issues.

A prototype engine bay door assembly was built and tested at 180°C for flight certification. The engine bay door consists of an inner skin and co-cured outer skin assembly with eight transverse stiffeners. The stiffeners were designed with ‘J’ sections. The door size was 1.5 m length, 1 m width and 0.4 m overall depth. The co-cured door was developed using autoclave moulding. Two doors were installed in prototype aircraft and successfully flown.