Thursday, 7 August 2014
Materials innovations driver for EEV ventures
REDUCTION in vehicle weight is a major attribute towards achieving fuel economy in energy-efficient vehicle (EEV). Henceforth, developing low-cost lightweight materials is now becoming one of the major focuses within the global automotive community.
Although well designed parts and components will help reduce the vehicle weight, however, right material selections for all components are better approach to achieve higher degree in their weight reduction.
Advanced materials are now being incorporated into the vehicle design, including body, chassis, suspension, power train and interior features, such as seats and fittings.
Most developmental work is focused on advancing the characteristics of materials, including aluminium and magnesium, alloys, ultra-high strength steels, carbon fiber and polymer composites.
To maintain compatibility with the current manufacturing assets within the automotive industry, application of advanced high strength steel (AHSS) is still preferred in the short- to middle-term venture towards EEV.
AHSS has the potential to reduce parts and components weight, especially those in the strength limited structural design, by as high as 25 per cent.
AHSS cost more than the current regular steel by about 15 per cent, but still cheaper, although heavier as compared to lighter materials, such as aluminium and magnesium. Steel, being alloyed with nickel and titanium, demonstrates increase in strength with relatively lighter in weight.
Thinner AHSS, coupled with right design approach, may reduce the weight of components in its application.
Lightweight aluminium and its alloys have been successfully exploited due to years of developmental work within the aerospace industry.
Aluminium alloys have been well developed and their metallurgical aspects are reasonably understood.
Existing processes to shape the material into components are continuously being enhanced, and new processes are being introduced to achieve better production efficiency and quality output.
Aluminium alloys have entered automotive application in a broader spectrum in the last few decades. Body-in-white structures, power train components, engine parts, hood and panels are among its applications by automotive designers towards weight reduction exercises.
A reduction of some 25 per cent in weight is achievable with aluminium as compared to the steel materials used in most vehicles.
Magnesium and its alloys are currently the lightest material having the potential for automotive lightweight component application, achieving some 60 per cent in weight reduction against the current steel materials being employed.
However, magnesium widespread application is still limited due to its high cost and price volatility.
Carbon fiber reinforced polymer composite, five times stronger than steel, but only one third of its weight, is the most promising lightweight material applicable for automotive, such as body panels.
The material has the potential of reducing some 60 per cent of the vehicle body weight. The composite imparts high strength in the body structure and is able to resist impact loads. Widespread application, however, is still limited due to the cost of carbonisation process to produce the carbon fiber input material.
Metallic metric composites are now gaining ground in automotive applications for engine parts and components.
Aluminium matrix composites, although still costly, have the potential of replacing heavy steel components, such as brake discs and drums, cylinder blocks, cylinder liners, pistons, crankshafts, camshafts, valves, push rods, connecting rods, brake calipers and turbo exchanges.
Various local universities have been involved in metal matrix and fiber polymer composites. Although the research initiatives are mostly of academic exercises in nature, the accumulated knowledge can be useful for lightweight material development in the near future by the local automotive industry players.
Automotive aluminium parts and components manufacturers have long been established in the local scene.
The support of trained local metallurgists and material engineers in various advanced materials is crucial for their advancement into the manufacture of lightweight components for future EEV initiatives.