Facing the Challenge for Vehicle Crashworthiness
Because customers worldwide are demanding safe cars and governments are regulating crashworthiness more strictly, engineers are selecting materials and designs that make vehicles safer, year after year. The steel industry has been facing the challenge by reinventing steel over time and pioneering a whole new class of materials that are over 50% stronger than a decade ago. At the core of this innovation lies the Advanced High-Strength Steel (AHSS) family, which embraces safety in all possible ways.
Recent studies show that high strength steels are the fastest growing material in today’s vehicles, contributing to ever increasing safety performance:
Growth of AHSS
The development of more critical crash testing and vehicle safety standards year-by-year have resulted in new vehicles with much improved front, side, rear and roof impact performance. Evolving crash test requirements therefore dictate auto body structures design and material. There is consensus in the automotive supply chain that safe vehicles can be designed with reduced weight if care is taken in the design phase. In other words, materials’ properties can be optimized through engineering design to avoid excess or redundant mass in the structure.
The table following shows a strong collection of AHSS grades in the steel material portfolio, and compares grades that were developed around the time of one of our major WorldAutoSteel projects, the Ultra Light Weight Steel Auto Body – Advanced Vehicle Concept (2002) with FutureSteelVehicle (2011), and the newly published AHSS Application Guidelines (V5.0). This chart is just a small representation of the efforts that the steel industry is investing to continue reinventing steel for automotive applications.
Steel is not a dormant material—in fact, it is a very sophisticated material, that can be changed with chemistry and process modifications, to achieve an incredible band width of properties and capabilities. Steel continues to reinvent itself to new, better, stronger, more formable materials. It’s also interesting to note the reach into GigaPascal (+1000) strength levels, shown in the tables. Some of these Gigapascal steels have properties that make them as formable as some of the traditional steels, such as HSLA.
- Global steel industry engineering studies (such as ULSAB and ULSAB-AVC, among others) show that a combination of new Advanced High-Strength Steels, together with the use of modern engineering design and computer-aided engineering (CAE) tools, can produce vehicle structures at least 25% lighter than previous vehicles.
- New steels have been designed to perform in different ways according to the requirements of different crash loads.
- Dual phase or TRIP steels are commonly used to ensure high energy absorption in frontal and rear crumple zone structures, while other Advanced High-Strength Steels are used to resist intrusion against side impact and roof crush
- Automakers are talking about the use of Advanced High-Strength Steels in their new production vehicles and the mass savings and benefits they are achieving.
Examples are plentiful among carmakers today that suggest that vehicles become safer as they incorporate more high-strength steels into the vehicle structures, as measured by crash tests statistics, while reducing mass significantly. Here’s just a few that you can read about our Steel Muscle in New Vehicles feature.
Sources: Data from car manufacturers • Study by Ducker Worldwide (Great Designs In Steel 2007)