Safety assessment of the reinforced ROPS system of the B14 bulldozer

According to the requirements of the technical regulations of the Customs Union, all bulldozers must be equipped with a ROPS operator protection system when the unit overturns. The B11 and B14 bulldozers manufactured by the Chelyabinsk Tractor Plant have the same hexagonal cabin. However, the different weights of these bulldozers do not allow using one ROPS. The aim of the study was to upgrade the ROPS protective system of the B11 bulldozer for use on the B14 bulldozer. The assessment of ROPS compliance with safety requirements was carried out on the basis of fullscale experiments in accordance with GOST requirements. The weak points of the protective cabin were initially identified. The ROPS structure reinforcement included increasing the rigidity of the attachment point (side clutch housing) and strengthening the structure itself by welding reinforcing angles to the upper part of the struts. Subsequent tests confirmed the increase in the loadbearing capacity of the reinforced ROPS structure. The reinforced ROPS absorbed the required impact energy of 40.9 kJ at a deformation of 355 mm under lateral loading. The required load of 217 kN was achieved with a deformation of 390 mm. After removing the lateral load, the structure with plastic deformation was additionally subjected to vertical loading. No penetration of ROPS structure parts into the limited volume area simulating the operator's position was observed. This confirmed the compliance of the reinforced ROPS structure with safety requirements for its operation on the B14 bulldozer.