Vehicle underbody structure with lightweight PU composite

"While the Design Challenge focused on a vehicle that would be available in 2020, Mazda designers set their sights on a lightweight vehicle that, among other things, could be mass produced using materials technologies that exist today," said Bruce Benda, Vice President, Automotive Marketing, Bayer MaterialScience LLC (BMS).

As a benchmark, Mazda used the featherweight MX-5 Miata, which tipped the scales at a little more than 2,000 lbs (race specifications). The company then carried out a systematic process of weight reduction and consolidation. Major weight savings were achieved by using unique design methods and materials in key areas.

Specifically, a bonded two-piece monocoque structure, similar to a Formula One car, is used for the safety cell, subframes, body panels, and interior surfaces. Mazda determined that manufacturing of this structure could be automated using BMS's Baypreg F polyurethane composite sandwich. Use of this material could lead to a safety cell/body panel weight of 100 lbs compared with the MX-5's 665 lbs, according to Mazda specifications.

Elsewhere, the MX-0 concept utilises automotive glazing that could be produced using BMS Makrolon polycarbonate to replace heavy glass, reducing the glazing mass by up to 50 %. The concept vehicle also uses Baytec polyurethane for the wheels and incorporates Baydur STR for structural components. Ultimately, the MX-0 would weigh in at an airy 999 lbs.

In 2009 the average light vehicle weighed 4,108 lbs, according to federal statistics.

BMS offers innovative options that help provide significant weight savings, part integration, aesthetics, design freedom and performance enhancements using engineering thermoplastics and polyurethane composite technologies such as:

The adoption of lightweight polymers to replace traditional materials such as glass and steel in exterior applications, including window glazing and body panel components.Polycarbonate and polyurethane roof modules that reduce weight and lower the vehicle centre of gravity.Underbody applications that assist with battery location and sound reduction along with providing the potential for significant parts reduction/consolidation.