ASSESSING SAFETY CONFORMANCE OF ROPS SYSTEM IN B10 TRACTORS
Abstract
The driver’s safety in the event of a vehicle rollover is a very important issue. Therefore,
a mandatory certification requirement of any vehicle is to assess the safety of the protective
structures of ROPS cabs. The safety of tractor cabs is assessed by full-scale experiments. Due to
modern computer technologies, we managed to assess the safety of a tractor cab based on a numerical experiment. The paper presents a mathematical model for assessing the safety of protective ROPS structures of an industrial tractor B10. A tractor rollover is simulated with a series of
static loads (lateral, vertical, and longitudinal). Plastic deformation of the protective structure
makes it possible to minimize the expected crash-impact energy. A mathematical model of simulation tests was developed using the finite element method. To take into account the plastic state
of the structure, the static problem was stated and solved by methods of nonlinear analysis taking
into account the effect of large displacements. The calculation results showed that the expected
crash-impact energy of 40,867 J for a 25-ton B10 tractor was achieved at a displacement of 261 mm
and a lateral force of 229 kN. The structure remained functional under its subsequent loading
with a vertical force of 500 kNand a longitudinal force of 170 kN. Its performance criterion was
intact limited space of the driver’s supposed location. A full-scale experiment confirmed the adequacy of the mathematical model and the safety of the protective structure.
The experimental crash-impact energy was achieved at a displacement of 261 mm with a lateral
force of 243 kN. The value of the experimental force differed from that of the calculated force by
less than 4%. The rate of energy gain was tested additionally. To this end, we plotted the force
against the structure deformation. The deformation energy was calculated as the area under this
curve. The value of the experimental energy differed from that of the calculated energy by less
than 7.3% over the entire range of studied structural deformations.
