Feasibility study of a front underrun protection device using different materials for industrial vehicles

This research investigates the utilization of innovative materials for a front under-run protection device (FUPD) for industrial vehicles, a crucial component for ensuring the safety of car drivers in the event of an accident involving such means of transportation. The traditional FUPD component, typically constructed from steel, features a square profile measuring 100x100x1930 mm with thickness of 3 mm and is welded to the supports. As a safety device, its homologation adheres to European standardization, which outlines three load conditions. It has been observed that the most hazardous condition involves an applied force on the external part of the FUPD equivalent to 60 kN. The initial innovative configuration is made using glass fibre reinforced polymer (GFRP), produced via pultrusion, and maintains the same geometry as the traditional component but with thickness of 6.5 mm. Due to the differing material properties of the supports and the FUPD, it was decided to connect these components using bolts. This configuration was employed to compare numerical simulations with experimental tests; such tests have been executed on a test bench specifically realised for a system developed to represent the real vehicle, where a part of the chassis is attached with the aim of simulating a fixed support for the studied assembly. A cylinder applies the load to a plate whose geometry is defined by the cited regulation; the plate is linked to the cylinder through a hinge, in order to follow the deformation of the analysed components. Strain gauges and load cells have been applied to the FUPD with the aim of collecting the data needed to do the comparison with finite element analysis. Following positive results, then the innovative structure has been optimized with increased thickness to withstand the applied stresses effectively. Subsequently, a second solution utilizing carbon fibre reinforced polymer (CFRP) was investigated, featuring a distinct geometry achieved through filament winding. An elliptical, non-constant section was chosen. To affix the device to new supports, an adhesive epoxy was applied. In both new configurations, the supports were designed in aluminium and adjusted to accommodate the new geometry and joining method. The results indicate a weight reduction of approximately -55% for the CFRP solution and around -18% for the GFRP solution compared to the traditional steel component. Although both solutions entail higher costs than the traditional approach, the investment can be amortized over a few years, leading to reductions in fuel consumption and vehicle pollution emissions.