Modern cars rely on lightweight building materials to reduce their overall weight. This is effective for multiple reasons, one of them being lower fuel burn. Having a lightweight vehicle is also good for maintenance costs and overall value. But… how can we achieve this and what does the future hold for the car building industry?
The lightweight and strong capabilities of aluminium can be applied to at least 26 parts used in the car building process: sidewall, roof crossmember, roof-rail, IP crossmember, cowl, strut tower front, longitudinal upper, longitudinal front, crash management system, firewall, A-pillar, roof, rear-wall, strut tower rear, floor, longitudinal rear, C- and B-pillar, crossmemeber rear and crossmember floor, sill, tunnel, door panels, door frame, door crash management and the reinforcements for the door hinge. Using aluminium, for instance, will lead to a significant reduction in a vehicle’s mass, which leads to better fuel economy and lower emissions. It also contributes to safety and better engine performance. Aluminium is also a 100% recyclable material, meaning it can be re-used over and over, as needed.
A study performed by the Aluminium in Transportation (The Aluminium Association, Inc.) has revealed the strongest parts which can be made out of aluminium are the strut tower front, longitudinal rear and B-pillar. The stiffest are the rear crossmember and the door hinge reinforcement mechanism. Aluminium components are able to reduce a vehicle’s total weight by around 40%, compared to steel versions.
Environmental aspects are also important. Aluminium is the clear winner in greenhouse gas emissions, compared to steel and magnesium. Besides lower emissions, aluminium uses less energy to manufacture and requires less energy from the vehicle’s engine and fuelling system. Aluminium comes with 20% energy savings in its entire lifecycle, 5% better than magnesium. CO2 emissions are also 20% lower when using aluminium, instead of steel.
Carbon-fibre is a lightweight and strong materials, initially reserved for racing cars to improve performance and increase speed. Today, carbon fibre is used all around and inside vehicles, usually for trim pieces, interior design and exterior panels. Carbon-fibre is a flexible material, fabric-like that combines with a polymer to mould it into the shape of an automotive part. Various technology innovations have managed to reduce the price for manufacturing carbon-fibre parts significantly. However, it has limited applications, mostly for custom-made cars and those in the luxury and medium-to-high price ranges.
Thanks to its strength, carbon fibre is also used in structural elements, such as roof elements, supporting roof pillars, and door frames. It hasn’t, however, gone into production for the chassis, which is reserved for steel and aluminium applications.
The first-ever production car with a carbon-fibre monocoque design was the famous McLaren F1.
Another entry on the list of high-performance lightweight materials for automotive applications is magnesium alloy. With lightweight characteristics, improved strength and the possibility to mould and cast very easily, this innovative material is made to improve vehicle performance and increase strength. The AZ and the AM series, in particular, are stronger than other materials used in cars today, being resistant to corrosion and having excellent mould casting qualities.
Magnesium is a low-density material, with limited use in the automotive industry, mostly employed for die-casting. It’s so lightweight, in fact, that it’s 36% lighter than aluminium, per volume and 78% better than iron. The alloy version manages to offer the highest strength-to-weight ratio of all the structural metals used.
Magnesium is abundant, meaning large-scale industrial use is viable and it recycles well. Magnesium alloy usually has around 20 chemical elements in its composition (Ag-Al-C-Ca-Ce-Cu-Fe-Gd-Li-MgMn-Nd-Ni-Sc-Si-Sn-Sr-Y-Zn-Zr).
The Lightweight Automotive Materials Program
Aimed to promote the use of lightweight materials in today’s modern vehicles, the U.S. Lightweight Automotive Materials Program (LAMP) helps create lighter, stronger and better material for vehicle manufacturing. The people responsible have been working on a set of software solutions and collaboration with industry representatives. The aim is to create lightweight materials, able to reduce the vehicle’s weight, lead to better fuel consumption, lower emissions and stronger automotive parts.
At the moment, there are nine projects under the LAMP. Each of the projects relies on high-performance computing, as well as modelling and simulations, to improve the selection process and optimise supports for lightweight applications. These tools are made to improve th design phase of car-building.
The program aims to create better materials, without compromising cost-effectiveness, performance, safety and recyclability.
(Featured image: SUCars, YouTube – youtube.com)