Development and crashworthiness evaluation of a lightweight roller-type side underrun protection device for heavy trucks

Side underride collisions expose passenger-vehicle occupants to severe intrusion because the primary energy-absorbing structures of the car may pass beneath the truck body. This study evaluates a lightweight roller-type side underrun protection device (SUPD), adapted from the controlled-deflection principle of roadside roller barriers, against a conventional rail-type SUPD. Three-dimensional models were prepared in CATIA and analysed in LS-DYNA using a Toyota Yaris finite-element vehicle at 56 km/h and impact angles of 30°, 60°, and 90°. The comparison considered peak equivalent stress, resultant displacement, peak guard-vehicle contact force, internal energy, and assembly mass. Numerical quality was assessed through mesh-quality checks, global energy balance, hourglass-energy control, and use of a previously validated public vehicle model. Relative to the existing SUPD, the roller-type design reduced peak stress by 69.7%, 79.9%, and 75.6% and reduced displacement by 11.4%, 18.0%, and 12.0% at 30°, 60°, and 90°, respectively. Peak contact force decreased by 52.1% at 30° and 42.5% at 90°, but increased by 37.0% at 60°, indicating an angle-dependent load-transfer mechanism. The roller-type device absorbed 50.7–88.3% less internal energy because it deformed less and redirected part of the impact through rolling and sequential contact. Its mass was 175.0 kg compared with 352.3 kg for the conventional design, a reduction of 50.3%. The results support the roller concept as a promising lightweight deflection-oriented SUPD, while experimental validation, rate-dependent rubber calibration, longer simulation duration, and geometric sensitivity studies remain necessary before implementation.