A blend of benefits

Patrick Loock, segment business owner for products and applications at leading composite technology company, Exel Composites, explains why hybrid composites are the perfect mix in helping manufacturers get the best of both materials.

 

Hybrid vehicles are taking the automotive industry by storm, as the growing momentum for cleaner travel is driving greener options into the forefront of the industry. As hybrids boast both a conventional engine and electric battery power, drivers get the best of both worlds. However, many aren’t aware that the hybrid concept also extends to composite materials.

By definition, a hybrid is achieved by combining two different items together so that the end result contains qualities relating to both of them. If we also think about defining composites, resin and fibre are combined to form a material that is better than the two original materials.

Hybrid composites take this one step further by combining two or more reinforcement fibres. Carbon fibre and fibreglass are commonly used, although it is possible to produce a hybrid using a variety of other fibres — such as natural ones. By using a hybrid structure, the optimum ratio of both materials’ mechanical properties can be reached to cater for the needs of an individual application.

Bringing the benefits

Hybrid composites have many advantages. Using a hybrid of fibres makes it possible to combine the benefits of multiple fibre types while simultaneously reducing their weaknesses. It is thanks to these benefits that hybrids can be used across a range of industries and for a variety of products.

Perhaps the most obvious boon of using a hybrid is its economic value. Composite materials aren’t particularly known for their modest budget and it’s rare to see, for example, a car made with using mostly carbon fibre due to its steep price. Hybrid composites can offer a cost-cutting solution to customers, as combining carbon fibre with a less expensive fibre reduces the amount of expensive product but still allows end users to reap its benefits.

Combining those fibres into a composite solution would undeniably enhance its robustness and create a more durable material. It is also favoured for its light weight, so combining carbon fibre with fibreglass would provide customers with an ideal option for applications where low density is an essential design consideration, such as in aerospace.

However, one of the drawbacks of carbon fibre is that it is brittle and breaks more easily upon impact. By combining carbon fibre with a more flexible fibre, such as fibreglass, manufacturers can improve the rigidity of the material and increase its impact resistance. Furthermore, carbon fibre conducts electricity — a quality that can be viewed as both an advantage and a limitation, depending on where it is applied.

Fibreglass composites, on the other hand, are insulators and can resist the flow of electric charge. It’s a case of opposites attract — more carbon fibre can be applied to increase the electrical conductivity of the finished product, while more fibreglass can help insulate it for applications such as electrical enclosures, where conducting currents could damage equipment.

The where and how

The fibres in hybrid composites can be arranged in multiple ways, depending on the desired outcome. At Exel, we manufacture a range of hybrid composites using continuous processes to provide customers with an outcome that is tailored to their requirements. We would select the type of fibre that would fit to your final expectation in terms of properties. Using the pultrusion method to permeate the fibres with a thermoset resin and pull them through a heated die for curing, we can manufacture hybrids in several different ways — depending on how and where customers want to use their benefits.

For example, different fibres can be mixed together so that they are evenly blended throughout the composite. We can also create hybrid profiles and tubes that are primarily made using fibreglass, with carbon fibres strategically weaved throughout the product for added strength. Another strength-enhancing option would be to manufacture a product using one type of fibre on the inside and with a strong carbon fibre outer shell. On the contrary, we can place pigmented fibreglass on the outside of the product to vary the composite’s colour and switch up its aesthetics.

While all these methods are possible, an understanding of the best solution for the end requirements is essential. When developing a hybrid composite, both the mechanical needs of the product and the economical limits of the customer must be considered.

Hybrids are gaining traction in industries beyond automotive, because they give customers the option to enjoy new characteristics. We’re often told that we cannot have the best of both worlds, but composites make it possible. Blending two materials together to form a hybrid composite doesn’t only mean that we can enjoy the benefits of each material, but a combination of different fibres that creates a whole new set of qualities that cannot be achieved using just one type of fibre or one specific material.

www.exelcomposites.com