May 11 2004
Lightweight materials may find exciting opportunities in the automotive industry as a means of increasing fuel efficiency. With 75 percent of fuel consumption relating directly to vehicle weight, potential weight reductions that result in improved price-performance ratio stimulate usage of lightweight materials.
“Lightweight materials such as plastic are ideal to improve fuel efficiency and design flexibility without compromising on performance or safety,” explains Technical Insights Research Analyst Sathyaraj Radhakrishnan. “Reduced tailpipe emissions and improved corrosion resistances are some of the other added benefits of lightweight materials.”
The automotive industry can expect an impressive 6 to 8 percent improvement in fuel usage with a mere 10 percent reduction in vehicle weight. This translates into a reduction of around 20 kilogram of carbon dioxide per kilogram of weight reduction over the vehicle's lifetime.
A survey of the European auto industry emphasizes the success of lightweight plastics in vehicle weight reduction. Compared to traditional materials, plastic bumpers, engine covers, and fuel tanks are 10.4 kg, 4.2 kg, and 5 kg lighter, respectively. Lighter vehicles facilitate easier braking, reduced collision impact, and superior driving experience.
Apart from plastic, magnesium alloy, which is two-third the density of aluminum and one-fourth that of iron and steel, and equally durable, is making inroads into the automotive industry. With the engine comprising the bulk of a car’s weight, magnesium’s capacity to reduce engine block weight by 66 percent is a significant achievement.
Though magnesium alloys are more expensive, they are recyclable and offer unique advantages over steel and aluminum. For instance, magnesium provides design flexibility and is highly moldable into complex components that operate at elevated temperatures. This stimulates its usage in several under-hood applications.
Metal matrix composites (MMCs) are also promising lightweight materials. However, to reach their full potential in the automotive sector, significant cost reductions in raw materials, fabrication methods, and process improvements are essential.
MMCs based on the aluminum-silicon carbide system find their niche in power train and brake applications. The embedded SiC particles magnify the mechanical and wear properties while the high thermal conductivity of the matrix increases the functionality of brake rotors.
Lightweight materials’ invaluable contributions extend beyond the automotive sector. Lightweight composite materials combine durability and lightness and are successful in the aerospace industry, mass-transportation components, high-rise buildings, and racecars.
Such composite materials have extremely high strength-to-weight and rigidity-to-weight ratios coupled with exceptional thermal insulation properties. In fact, composite cables operate at higher temperatures revolutionizing electricity transmission and offering numerous benefits over conventional wood, concrete, and steel cables.
“Composite cables are an innovative means to transport electricity to remote parts and permit installation on existing rights-of-way, “explains Radhakrishnan. “Although they are relatively more expensive than steel structures, lower infrastructure costs, doubled power transmission, and reduced sags are some of their key advantages.”
However, viability analysis of a new lightweight material to the entire system may be crucial to gain an all-round benefit. For example, the chosen material must be adaptive and tailored around the system rather than designing the system based on the material.
Lightweight Materials Technology, part of the Transportation Vertical Subscription Service, provides a comprehensive analysis of the present and future development trends in lightweight materials. It highlights key technical challenges and drivers influencing growth, and provides in-depth examination of cutting-edge developments. Executive summaries and interviews are available to the press.
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