Design approach of heavy goods vehicle underrun protection using morphological analysis

Abstract

One of the most harmful of two-vehicle crashes to passenger vehicle occupants is when the front of passenger vehicle hits and passes underneath the rear of truck. It resulted in 23% of total death from two-vehicle crashes with a truck in 2018 based on data from the U.S. Department of transportation’s Fatality Analysis Reporting System (FARS). To reduce the violence of such accidents, the rear underrun protective device (RUPD) is installed on the rear of heavy goods vehicle (HGV), to cause the crumple zone of the impacting passenger vehicle absorbing the impact energy and prevent the impacting passenger vehicle from getting crushed under the HGV. This article demonstrates an approach to design the RUPD based on design inputs, including the structural strength, the local RUPD builders, and the variation of commercial HGV types in Thailand. The morphological analysis is applied along with brainstorming among design team, local manufacturers, and government agency, to generate a total of 72 potential RUPD solutions. In this study, three potential RUPD designs were proposed as RUPD prototypes for different HGV types to investigate their structural strength in terms of strain, deformation, and maximum reaction force. The explicit dynamic finite element (FE) method was implemented to accurately simulate the structural strength of the RUPD prototype since its results were validated by the real test of full-scale prototype with reference to the UN R58 standard. From the results, all proposed RUPD prototypes satisfied the UN R58 standard and are not violated by test loads at all relevant positions. In addition, different designs of the protective beam, which was found to be the main load-bearing resstive component of RUPD, were proposed. Their structural strength and energy-absorbing capability were examined by FE simulation to allow local RUPD builders to have alternatives for RUPD fabrication depending on their resources and applications. Besides, the proposed design approach in this study could be further applied as a guideline design for other RUPD types in a commercial scale.