RESEARCH IN IMPACT OF CARGO VEHICLE LOAD WEIGHT ON BRAKING SYSTEM ELEMENT HEATING PROCESS IN SINGLE EMERGENCY STOPPING

The paper presents the results of the simulation tests of the impact of the total vehicle weight (with load) on heating discs and brake pads. It was necessary to develop a mathematical model describing the braking process of the truck to perform the simulation. The necessary material features, such as: coefficient of friction, thermal conductivity, density and thermal capacity at constant pressure were determined experimentally using laboratory equipment. Vehicle technical data were obtained from the manufacturer. The tests were carried out for constant initial speed - 90 km.h(-1). For the purposes of this paper, a CAD model with the working elements of the braking system (disc and pad) was developed. The geometry of the system has been simplified relative to real parts. The simplification involved removal of unnecessary complicated geometry that does not have a significant impact on the final result of the tests, but may cause unnecessary compaction of the mesh. The finite element method (FEM) was used for the calculations. Appropriate equipment was also needed. In the case under consideration, a computer equipped with Comsol Multiphysics software was used. This is the software commonly used to calculate the distribution of temperature fields. As the result of calculations, this software allows to measure the temperature at any time and any point of the tested system. In this case, the temperature was measured at two points: inside the brake disc and inside the brake pad. In both cases at a distance of 0.05mm from the friction surface. The results clearly show that the mass of the vehicle has a direct effect on the maximum temperature of the friction linings. With overloaded vehicles, it reaches dangerously high values. Overheating the brakes may result in the fading phenomenon and loss of the stopping ability.