After many years with familiar and widely available creative materials, it could soon be time to abandon our wood and metal creations for a more sustainable outlook. Has the Composite Age dawned, and if so, what does it look like?
This exploration into what a composite is will follow four short summary discussions, that by the end will give you a simple but sufficient idea of the materials contemporary engineers are looking to prioritise:
- What Does Composite Mean?
- The History and Types of Composites
- Unique Properties and Applications
- Are Composites the Future?
Composite? I Barely Know It!
Composite is not a widely used term in everyday living for the general populous. Without an engineering background it’s most likely to pop up as a verb within the context of ‘combining’ two or more things together to create something new, for example in photography; the digitally manipulated image was composited using two different photos. In fact, the term composite stands for the same thing as the adjective used in engineering and as the subject for this exploration.
Composite materials and advanced materials, more commonly referred to as composites, are materials made up of two or more materials unlike one another, that when combined are able to
create unique solutions for specialised jobs. This can include increased strength in stiffness and density, reduced weight and flexibility, or conductive and resistant properties. Because composites improve on their base material attributes, they are often looked to for combating multiple engineering and construction requirements at once. For example, in kinetic applications, it may be necessary for materials to be strong as well as lightweight; whereas metal is ideal for stiffness, it is not often light enough to appeal to all conditions. With concrete, the material may be a durable and resistant solution for most outdoor and building applications, but with it comes the risk of weak tensile strengths and brittleness.
The next time you enter a building or a vehicle, think about the requirements its materials need to adhere to. Do they need to protect against weathering, or resist vibrations and extreme temperatures? A composite material can be used to comply with multiple needs, and thus, provide a new and unique way of reducing the number of materials needed.
Results of a Long History
Composites may sound like new and futuristic materials, but they in fact predate the modern engineering materials of today.
Composites made from straw and mud were used by tribes across the globe to create strong and durable homes over 6000 years ago, while plywood—layered sheets of wood glued together—has been discovered to be used by ancient Greek and Roman civilisations as a stronger alternative to natural wood with pleasing aesthetics. Other composite materials such as cartonnage was employed by the Egyptians from 2100BC to combine layers of linen or papyrus with plaster to create death masks and painting canvases. Similarly, if you remember making paper-mâché at school, then you’ve created a composite material. Even aforementioned concrete is a composite that can be made from different types of aggregate and has been in use since its initial mention by the Roman architect Vitruvius in his book De architectura, which dates around 25BC.
One of the more popular composites in today’s age stemmed from the beginning of the 20th century, and the creation of the world’s first synthetic plastic by Leo Baekeland, coined Bakelite in 1909. 23 years later, engineer Games Slayter accidentally projected compressed air at molten glass to discover it mass produced glass fibres. The discovery was quickly patented as fibreglass, and from quick interest by the aviation industry, both Baekeland and Slayter’s inventions were combined to create the first fibre-reinforced plastic, that then went on to see commercial use in aircraft in the 1940s. By the early 1960s, carbon fibre-reinforced plastic was being utilised in aerospace and automotive applications.
This is just scraping the surface of the types of composite materials that are in use today.
Below are the most common variations, each with different capabilities:
- GFRP – Glass Fibre Reinforced Plastic
- CFRP – Carbon Fibre Reinforced Plastic
- AFRP – Aramid Fibre Reinforced Plastic
- BFRP – Basalt Fibre Reinforced Plastic
- PMC – Polymer Matrix Composites
- CMC – Ceramic Matrix Composites
- Reinforced Concrete
On top of this, composite thermoplastic polymers such as PEEK (polyether ether ketone) can be used to fabricate parts through injection moulding and extrusion processes, or CNC milling as a solid state. As to each of these composites’ unique properties, we’ll explore this shortly. For now, let’s summarise the main advantages of composites over metal or wood alternatives.
- Low-cost manufacture – Manufacturing composite parts has been continuously streamlined to reduce production times and speed processes with specialised equipment, such as filament winders and composite cutting machines.
- Durability – Composites across the board show to last longer than alternative materials, requiring less maintenance.
- Lightweight – Thanks to its fibre layup, FRP can be hundreds of pounds lighter than the likes of steel while performing the same duties in engineering.
- Strength – Along with weight reduction, composites have proven to be stronger and displace tensile stresses to certain areas with particular fibre directions and build-up.
- Eco-friendly – The manufacture of composites greatly reduces the carbon footprint of factories and their applications.
An Important Role in Society
Right, let’s talk application! This opens an endless list of possibilities as composites are always finding work in unique and specialist situations, and this is down to the properties that characterise each material.
Search for a composite trader or manufacturer, and you will most likely find that their composite materials are being used for pretty much every engineering industry you can think of. This will certainly include, but may not be limited to; automotive, aerospace, marine, construction, industrial, medical, biotech, sport, and green energy sectors. Composites will find numerous roles within each sector, from lining pipes, tubes and cables to machinery parts, brackets, hinges, and engine components. In construction applications, FRP composites reinforced with carbon fibre and glass have been tested alongside steel membranes with beneficial results. CFRP has a very low density, meaning larger parts weigh less than smaller steel parts, thus fewer separate pieces are required for construction projects. This is just one purpose, as CFRP is also linear elastic and very strong, with a high tensile strength up to three times as much as steel. GFRP is commonly utilised as a filament, thanks to its prominent water and chemical resistances.
Moreover, thermoplastics such as PEEK are employed across most industrial sectors including auto, aero, and medical due to the polymers’ resistant characteristics. Resilient to chemical wear, electricity and extreme temperatures make thermoplastics ideal for engine applications and specialised precision equipment, including pumps, valves, pipes, cable tubes, and surgical instruments. Properties of PMC carry almost all of the above advantages, with fracture and abrasion resistance, making the materials ideal for heavy gas and chemical environments such as offshore oil platforms and power stations.
Wherever there’s a hazardous or technically demanding role, you can be sure composites have a part to play in the operation.
Is this the Age of Composites?
If you’ve read this far then it probably seems almost silly to use nothing but composites in our everyday life.
While the positives and advantages certainly outweigh the negatives, the truth of the matter is metal and wood industry production continues to largely dominate across the globe. However, statistics show that since 2015 the market value of composite materials has risen by $20 billion, and by 2028 it’s estimated to reach $144.5 billion. Composite application is constantly increasing; Boeing unveiled its predominantly composite-made aircraft in 2014 Boeing unveiled its predominantly composite-made aircraft in 2014, as well as Airbus deploying its 53% composite airliner the same year. Recycling solutions for recovering composite material waste continue to improve, reducing manufacturing footprints for companies worldwide. Automotive applications have had a 60% weight reduction through composite utilisation, while the popularity of 3D printed composites has reduced customer costs on average by 50%.
Exploring the definition of a composite material has hopefully opened your mind to its multitude of possibilities. In the end, what will make or break the continuation of its application is exposure. It’s hopeful the subject of composites will become easier to understand for the general masses, in turn raising awareness of their capabilities and benefits that have been set forth in this exploration.