Innovations

The technology development effort is aimed at giving the scientific community a compact inexpensive telescope that would fit easily inside a CubeSat, a class of research spacecraft built to standard dimensions that can be deployed from a Poly-Picosatellite Orbital Deployer, or P-POD.

NASA’s CubeSat Launch initiative (CSLI) provides opportunities for small satellite payloads to fly on rockets planned for upcoming launches. These CubeSats are flown as auxiliary payloads on previously planned missions.

Small satellites are playing an increasingly larger role in exploration, technology demonstration, scientific research and educational investigations at NASA. These miniature satellites provide a low-cost platform for NASA missions, including planetary space exploration. They also allow an inexpensive means to engage students in all phases of satellite development, operation and exploitation through real-world, hands-on research and development experience on NASA-funded ride share launch opportunities.

The first ever carbon-nanotube resin mirror could prove central to creating a low-cost space telescope for a range of CubeSat scientific investigations.

Unlike most telescope mirrors made of glass or aluminium, this particular optic is made of carbon nanotubes embedded in an epoxy resin. Sub-micron-size, cylindrically shaped, carbon nanotubes exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Owing to these unusual properties, the material is valuable to nanotechnology, electronics, optics, and other fields of materials science, and, as a consequence, are being used as additives in various structural materials.

The use of a carbon-nanotube optic in a CubeSat telescope offers a number of advantages. In addition to being lightweight, highly stable, and easily reproducible, carbon-nanotube mirrors do not require polishing — a time-consuming and often times expensive process typically required to assure a smooth, perfectly shaped mirror.

To make a mirror, technicians simply pour the mixture of epoxy and carbon nanotubes into a mandrel or mould fashioned to meet a particular optical prescription. They then heat the mould to cure and harden the epoxy. Once set, the mirror then is coated with a reflective material of aluminium and silicon dioxide.

Many of the mirror segments in these telescopes are identical and can therefore be produced using a single mandrel. Carbon-nanotube mirrors can also be made into ‘smart optics’. To maintain a single perfect focus in the Keck telescopes, for example, each mirror segment has several externally mounted actuators that deform the mirrors into the specific shapes required at different telescope orientations.

This technology can potentially enable very large-area technically active optics in space, and can address everything from astronomy and Earth observing to deep-space communications.

Oxford Advanced Surfaces has been awarded a £233,000 grant by Innovate UK to develop surface treatments that can be used to create new lightweight composites from recycled carbon fibre.

The grant supports the Integrated Delivery Programme 12 (IDP12) initiative and OAS has won backing in the ‘light weighting’ category that supports feasibility studies into how the weight of vehicles, and therefore CO2 emissions can be appreciably reduced.

Together with the University of Manchester, OAS will use carbon fibre that has been reclaimed from a variety of waste sources during its feasibility study and the Oxfordshire-based company is confident it can deliver a new composite specification that will bring significant benefits to the automotive industry.

The company has 18 months to complete its ‘rescued carbon fibre for use in the automotive industry’ study. It aims to develop data sheets and prototypes that will highlight uses for the new composite material it will develop.

Joining carbon fibre composites to aluminium and other multi-material high-end products could become less expensive and the joints more robust thanks to a new method that harnesses laser technology.

The process, developed by a team led by Adrian Sabau of the Department of Energy’s Oak Ridge National Laboratory, could replace the practice of preparing the surface of the materials by hand using abrasive pads, grit blasting and environmentally harmful solvents. Using a laser to remove layers of material from surfaces prior to bonding improves the performance of the joints and provides a path toward automation for high-volume use.

Our technique is vastly superior to the conventional surface preparation methods, combined with the potentially dramatic reduction in the cost of carbon fibre polymer composites, this represents an important step toward increasing the use of this lightweight high-strength material in automobiles, which could reduce the weight of cars and trucks by 750 pounds.

The surface treatment of aluminium and carbon fibre polymer composite is a critical step in the adhesive joining process, which directly affects the quality of bonded joints. Aluminium surfaces typically contain oils and other contaminants from production rolling operations while carbon fibre surfaces often contain mould releases.

“These surface contaminants affect surface energies and the quality of adhesion, so it is critical that they are removed, adding that the laser also penetrates into the top resin layer, leaving individual carbon fibres exposed for direct bonding to the adhesive and increasing the surface area for better adhesion.

Test results support Sabau’s optimism as single-lap shear joint specimens showed strength, maximum load and displacement at maximum load were increased by 15%, 16% and 100%, respectively, over those measured for the baseline joints. Also, joints made with laser-structured surfaces can absorb approximately 200 percent more energy than the conventionally prepared baseline joints, researchers reported.

Sabau noted that the process also doubles the energy absorption in the joints, which has implications for crash safety and potential use in armour for people and vehicles. Tim Skszek of Magna International a project partner said;

The results are most encouraging, enabling the automated processing of a multi-material carbon fibre-aluminium joint. With this work, we were able to focus on addressing the gaps in technology and commercial use, and we look forward to applying these findings to products.

Researchers at the Department of Energy’s Oak Ridge National Laboratory have demonstrated a production method they estimate will reduce the cost of carbon fibre as much as 50% and the energy used in its production by more than 60%.

After analysis and successful prototyping by industrial partners, ORNL is making the new method available for licensing.

High cost has been the single largest roadblock to widespread use of carbon fibre as a strong, stiff reinforcement for advanced composites. ORNL’s new lower cost method builds on over a decade of research in the area. The researchers’ success promises to accelerate adoption of carbon fibre composites in high-volume industrial applications including automobiles, wind turbines, compressed gas storage and building infrastructure.

More than 90% of the energy needed to manufacture these advanced composites is consumed in manufacturing the carbon fibre itself. Reduction in energy consumption in manufacturing will enable earlier net energy payback—that is, the energy savings gained in using products made from lighter-weight material compared to the energy consumed in making the material. Similarly, ORNL is working as a technology partner at the IACMI to enable the use of low-cost carbon fibre composites in a wide range of next-generation clean energy products.

The photo shows carbon fibre being processed at a much higher throughput than is possible with conventional methods
The photo shows carbon fibre being processed at a much higher throughput than is possible with conventional methods

Carbon fibre is produced by converting a carbon-containing polymer precursor fibre to pure carbon fibre through a carefully controlled series of heating and stretching steps. In current commercial practice, the precursor, polyacrylonitrile or PAN is chemically modified and optimised to maximise the mechanical properties of the end product. The high cost of specialty precursor materials and the energy and capital-intensive nature of the conversion process are the principal contributors to the high cost of the end product.

Acrylic fibre of similar chemistry, however, is produced on a commodity basis for clothing and carpets – a high-volume product that costs roughly half as much as the specialty PAN used in the carbon fibre industry. ORNL researchers believed textile-grade PAN was a pathway to lower-cost carbon fibre, but laboratory-scale experiments couldn’t fully explore its potential at a production scale.

Extensive mechanical property tests have been performed on carbon fibre from the new process, and several auto manufacturers and their suppliers received quantities suitable for prototyping, with encouraging results.

Gary Jacobs, ORNL’s interim associate lab director for Energy and Environmental Sciences said;

Our R&D into process improvements and the extensive validation work at the Carbon Fibre Technology Facility provide manufacturers and end-use industries the confidence needed to invest in large-scale manufacturing, knowing there will be a market for this material.

Companies, including licensees of the new method, will be able to use the Carbon Fibre Technology Facility to refine and validate the carbon fibre manufacturing processes. ORNL will accept license applications for this low-cost carbon fibre process through May 15. Licensing information for manufacturers in the U.S. is available here.

The transport industry has for some time been engaged in the application of new lightweight materials for structural design, with advanced lightweight composites replacing traditional metal materials more and more in both structural and non-structural parts.

The rail industry could also benefit from the use of structural new materials. If a train’s car body is made of composite materials, the train’s weight would be reduced by 20 to 30%. These weight savings would result in lower energy consumption and a reduction of at least 5% of CO2 emissions.

Current European legislation does not allow train manufacturers to use composite materials when constructing train car bodies. The railway sector currently only uses composites for non-bearing structural components, with steel being most commonly used to construct a train’s car body.

One of the key obstacles to overcome has been the lack of suitable certification procedures addressing the specific operational requirements of a railway vehicle. The EU-funded REFRESCO project was set up to provide solutions to this and other obstacles, and pave the way for the adoption of new procedures that will allow for the use of composite materials in rail car manufacturing.

REFRESCO has benchmarked the most promising new materials being used both within and outside the transport sector and which could be integrated into railway rolling stock. After an analysis of certification processes and standards applicable to rail vehicle car bodies, the project found that the current European railway certification process gives opportunities for innovative solutions. However, the set of technical standards needed to prove compliance for composite car bodies is not yet in place and thus has to be developed further.

Following a gap analysis, the project concluded that even if some standards need adaptation for composites material behaviour, most can be applied to a composite car body shell without jeopardising safety.

When studying the practical structural requirements for the adoption of composite materials, the project focused on subjects such as strength, crash and fire resistance, noise and vibration, electromagnetic compatibility and maintainability.

The project studied the crash worthiness of composite materials in detail due to strict safety requirements. Composite materials behave differently from materials such as steel or aluminium, being more brittle and orthotropic, raising the question of the strength of a body-shell structure built from composite materials when a collision occurs.

Reference crash simulations were performed on current metallic designs to observe their behaviour and confirm current safety behaviour. Composite materials were integrated into a cabin structure shell, with initial results showing some cracking. However, the project saw that by reinforcing the composite structure or extending the surrounding metallic interfaces, it is possible to pass the collision scenario test.

The project also concluded that maintenance processes would also have to be modified if composite materials are introduced. Not only would maintenance buildings have to be equipped to service them, but railway technicians would have to be trained to be able to work with composites.

Currently, the prices of composites are higher than of steel constructions, but this is expected to change, as the automotive industry has been increasingly using them. The production of raw materials for composites is also increasing, that will probably lower their price further.

Although the REFRESCO project officially ended in February 2016, the project partners aim to utilise its results to work with regulators to update certification procedures, allowing the rail industry to take advantage of these promising lightweight materials.

Researchers at the DreamWind project are looking to develop a chemical substance that will separate composite materials from each other, allowing fibreglass components used in wind turbines to be recycled.

Denmark’s Aarhus University will collaborate with partners including Vestas and the Danish Technological Institute to develop new composite materials for wind turbine blades.

Associate Professor Mogens Hinge of Aarhus University’s department of engineering said;

Components made of fibreglass have to go through a difficult procedure before they can be reused, this entails separating the glass from the plastic, and you can only do this if you heat the material for a long time at 600 degrees Celsius, which is far from profitable from both an energy and an economic point of view.

Because it’s almost virtually impossible to recycle the composite materials used, old wind turbine blades are taken to enormous graveyards where the components are crushed and buried in landfill

According to researchers, the acute problem in the wind turbine industry inspired them to develop a solvent with the opposite properties, so that instead of binding materials to each other, it can separate them chemically with limited or no heating at all.

The idea is that the glass should be reused when it has been cleaned – for new fibreglass components for structures such as wind turbines, aircraft or cars. The researchers are initially focusing on designing an agent for fibreglass, and they say the first laboratory results are promising.

Innovation Fund Denmark has invested a total of 17.6 million Danish Krones (approximately $2.67 million) in the project, which, in the long run, can influence the recycling of composite materials outside the wind turbine industry. The parties expect to be ready with a chemical compound for separating fibreglass within four years.

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