Steel industry study examines untapped potential of advanced high strength steel to compete against aluminum and reduce mass significantly. Some efficient steel designs and materials found to contain less mass than similar aluminum components.
A study released today by WorldAutoSteel, the automotive group of the World Steel Association, showed a wide variation in efficiency among steel components in vehicles on the road today. If the association has its way, collision repair facility operators can expect to see more advanced high strength steel components
The study, “A New Paradigm for Automotive Mass Benchmarking,” further revealed that when aluminum closure components, such as doors, bumpers, hatchbacks, and decklids, are compared to efficient steel components of similar size, the 40 percent mass savings currently accepted as a standard measure of aluminum lightweighting capability is not nearly reached. The study also showed that while use of aluminum may achieve mass savings at the component level, that mass savings is lost when an entire system is measured.
The study, conducted by EDAG International, Inc., uses the A2Mac1 vehicle tear-down database of approximately 200 vehicles along with a benchmarking methodology. The methodology uses statistical regression analysis to isolate mass-efficient designs and compare lightweighting, as presented in a paper by Dr. Donald Malen, University of Michigan, and Jason Hughes, A2MAC1 Automotive Benchmarking at the Society of Automotive Engineering World Congress in April 2015.
A component structure that is identified as efficient is one that stands out statistically as much lighter than others of its kind of the same size, structural performance and material. For efficient steel, this could be due to the use of Advanced High-Strength Steels and/or because of a fully optimized design.
Comparing an efficient front bumper to an efficient aluminum design shows just an 11 percent savings. According to Malen, statistical benchmarking opens a whole database of today’s vehicles to the benchmarking process. With it, engineers can identify better, more realistic targets, saving time and money.
“First, this benchmarking method revealed a broad disparity in levels of efficiency among the steel component designs of similar size. But when comparing aluminum component designs to their efficient steel counterparts, the results were startling,” said Cees ten Broek, director, WorldAutoSteel.
The study actually found that the average aluminum component design was heavier than an efficient steel design.
“For example, the Malen and Hughes paper documented a 22 percent mass savings when comparing efficient aluminum doors to efficient steel doors. Our study confirmed that calculation. A similar comparison of front bumpers shows just an 11 percent savings. And when comparing an average aluminum design to an efficient steel bumper design, the aluminum bumper was 26 percent heavier,” said Ten Broek who noted that this is very different than currently accepted predictions in the industry.
An approximate analysis of the total vehicle curb weight change was conducted using the mass reductions shown in the steel and aluminum efficient designs. The efficient steel subsystems reduced vehicle curb weight by 6.5 percent compared to average steel subsystems. Aluminum subsystems reduce curb weight by 9.3 percent compared to average steel subsystems, a 2.8 percent difference.
Ten Broek said, “While steel has come a long way, the study shows additional lightweighting can be achieved through design optimization and advanced steels and steel technologies.”