Development of Hybrid Energy-Absorbing Reusable Terminal for Roadside Safety Applications

The hybrid energy-absorbing reusable terminal (HEART) is a newly developed crash cushion or end terminal to be used in highway safety applications to mitigate injuries to occupants of errant vehicles. HEART is composed of corrugated plates of high–molecular weight, high-density polyethylene (HMW-HDPE) supported on steel diaphragms that slide on a fixed rail. Kinetic energy from errant vehicles is converted to other energy forms through folding and deformation of the HMW-HDPE material. Many previous designs utilized plastic or permanent deformation of plastics or steels to accomplish this goal. However, HEART is a combination of plastic and steel that forms a largely self-restoring and largely reusable crash cushion. Consequently, HEART has a major life-cycle cost advantage over conventional crash cushion designs. HEART was developed through extensive use of finite element analysis with LS-DYNA. The simulation approach adopted for the development of HEART, construction details, and a description and results of crash tests performed so far to evaluate its performance are presented. Also discussed is some of the follow-up work currently under way for approval of HEART by FHWA as an acceptable crash cushion for use on the National Highway System.