Dynamic and static ROPS tests on modern tractors

A Roll-Over Protective Structure (ROPS) is a highly effective engineering safety control that can avoid or reduce the severity of injuries in the event of tractor overturns. Strength ROPS procedures were introduced in Europe in the 1950s. These tests require a level of energy based on the tractor reference mass and consider the driver’s clearance zone protection. The Code 6 of the Organisation for Economic Co-operation and Development (OECD) is a consensus performance standard established for agricultural front ROPS fitted on narrowtrack tractors. These tractors ROPS requires more attention because the clearance zone is reduced to preserve the normal operation in orchard and vineyard. Code 6 foresees dynamic and static procedures for the ROPS tests. Dynamic procedure is based on a 2000 kg mass oscillating and impacting the ROPS, instead static procedure takes into account a slow rate of load application until the energy level is satisfied. In the current study, according to the OECD Code 6, laboratory dynamic and static tests were carried out on a foldable ROPS fitted on a modern tractor. The work was focused on the evaluation of the ROPS behaviour when stressed dynamically and statically. Dynamic test was carried out on the tractor complete of wheels and attached to the ground, so that the ROPS and the tyres absorbed most of the impact energy. Otherwise, static test was carried out on the ROPS fitted on the tractor chassis without the contribution of tyres; the tractor axels were fixed on the ground and the whole energy was absorbed by the ROPS. Tests results indicate that the deflection obtained with the dynamic testing procedure is higher than that of the static one. The results seem to suggest that the dynamic testing procedure is more conservative than the static one. It could be advisable to extend the comparison between dynamic and static procedures to other types of modern ROPS so as to verify if differences continue to be observed.