Today, as automakers and suppliers struggle to meet conflicting requirements — tougher impact and fuel economy regulations at a lower cost to the end consumer — they are turning to advanced high-strength steel (AHSS) for creative solutions. AHSS is paving the way toward reducing weight and improving application performance.
Shape Corp., a leading automotive supplier in impact energy management, has been using Docol® AHSS in its Power B-Section bumper for many years. It allows for thinner steel gauges and reduced steel consumption by up to 20 percent. Shape Corp’s MonoLeg bumper, based on an exciting new design, offers the performance and mass of an aluminum bumper, with the cost advantage of a steel solution.
Designed for better impact performance
Updates to the IIHS and RCAR bumper test protocols include impacting beams into barriers that more realistically mimic other vehicle bumpers. Shape Corp. designed a geometry that counteracts both the torsion and bending demands of the IIHS and RCAR bumper test protocols. Blending the strength of the Shape Corp. Power-B bumper with the torsion strength of tubular sections, the MonoLeg improves torsion strength by 50% to combat the combined loading effect of these impacts.
Engineered to be lightweight
By taking advantage of the high mechanical properties of AHSS and applying them to an optimal geometric design, the MonoLeg helps achieve fuel economy demands, including CAFE standards. A reduction in mass from a conventional steel bumper is achieved by roll forming the Shape MonoLeg bumper from AHSS, up to 1700 MPa. The characteristics of the Shape MonoLeg bumper can match those of 7000 aluminum alloys.
Force-deflection curves from IIHS bumper barrier impacts demonstrate the effectiveness of the MonoLeg vs. traditional lightweight:
Balanced results
This makes the Shape MonoLeg a key product for OEMs trying to balance mass reductions to meet CAFE, achieve the performance to meet impact regulations and maintain a reasonable price point.
Benefits for bumpers using Docol® AHSS
The question of strength-to-weight ratio versus cost plays a key role in choosing bumper materials. Docol® steel helps you resolve this issue, bringing you the following benefits:
- Using Docol® AHSS in automotive bumpers can not only reduce vehicle weight while maintaining crash test performance, but it can save you money.
- Docol® AHSS exhibits a pronounced yield strength increase of about 150 MPa or more after work-hardening and bake-hardening.
- Docol® AHSS exhibits a strain rate hardening effect. This effect corresponds to an increase of about 100 MPa at the high strain rates that are involved locally in a crash event.