BMW April 2022

Even as vehicle manufacturers (VM) seek to produce lighter vehicles, motorists are demanding additional features. As consumers, we want safer cars – and that means making them stronger. But we also want comfort and convenience, adding further components and weight.

VMs are wrestling with the dilemma of satisfying these demands while dealing with the urgent, government-mandated needs to tackle emissions. The race is on to find lightweight materials that offer solutions.

A 10% reduction in kerb weight is said to decrease fuel consumption by up to 8% (source: Prescouter). It’s clear that if  VMs can manage to reduce structural weight they will improve emissions and range, as well as performance, acceleration, and braking.

The answer lies in using materials that are light but strong, and durable but reusable. Carbon fibre and composites do the trick, so a greater volume of vehicles now draw on their unique qualities.

Benefits to structure and weight

There are many advantages to using carbon fibre and composites: 

Weight: very light compared to both steel and aluminium, for example a Corvette’s carbon fibre body panel weighs a fifth of the steel equivalent (source: Car and Driver); early use of carbon fibre in F1 endplates removed 80% of the weight from these parts, which were previously made from aluminium or magnesium.

Efficiency: reduced energy use in production; more environmentally friendly.

Strength – 10 times  stronger than steel and eight times aluminium, if used correctly.

Flexibility: injection moulding removes constraints; highly recyclable and reusable.

Safety: while steel typically absorbs35J/kg, thermoplastics can absorb seven to eight times this energy (C-PEEK = 230J/kg), while thermoset composites can absorb about twice the amount compared to steel.

These materials are relatively expensive but offer greater production efficiency. Due to its flexibility, for example, more complex shapes can be achieved from moulding than is usually possible in the traditional metal pressing process. This means there is the potential for single press-moulded components to replace multiple parts that need to be joined.

Lightweight set to dominate

Latest estimates state the automotive lightweight materials market will grow at a compound annual growth rate – the metric investors use to measure growth over time – of 7.4% from 2019 to 2027. Meanwhile, market size is projected to grow from US$89.1bn (£64.3bn) in 2019 to US$157.7bn (£113.8bn) by 2027 (source: Prescouter). 

With this in mind shrewd repairers will prepare today for the steady increase in new forms of lightweight material. It’s vital to get to know damage and repair issues that are specific to these materials, to be aware of problems that aren’t always obvious to the naked eye. If a vehicle containing carbon and composite materials is sent to an uninformed body shop its technicians may not be able to complete the work – adding time and cost to repair.

Training lightens the load

Through its e-academy online platform, Thatcham Research provides up-to-the-minute training to ensure everyone in the value chain can be armed with knowledge of the latest trends and techniques in lightweight materials. The training modules offer key insights into the constraints and opportunities of repairing complex lightweight material repair. This begins with damage identification and testing, a particular problem when dealing with carbon fibre.

Also detailed in the training course are key hazards when dealing with composites – absorption, inhalation, injection and ingestion of materials – as well as associated repair processes including vacuum bagging.

As innovation drives efficiency on the production line, soothing cost concerns, the burden will fall on body shops to be fully competent in understanding, identifying and repairing these revolutionary new materials.

 

By Dean Lander