COMPARATIVE ANALYSIS OF THE STRENGTH OF TRUCK FRAMES MADE FROM PROFILES OF DIFFERENT SHAPES

Calculations were made on the strength of the hot-rolled channel made of low-alloy steel produced by the metallurgical plant “Metinvest” (Ukraine) and the lightweight cold-bent channel made of high-strength steel produced by the metallurgical plant “Voestalpine AG” (Austria) for the frame spars of a heavy-duty vehicle – the KrAZ-6510TE tractor unit, as the most powerful and a loaded car from the model range of KrAZ cars, with the determination of stresses in the spars and critical zones under the condition of strength and magnitude of the spars’ bending deformation from static loads and. The calculations were carried out taking into account the chemical composition and mechanical properties of the materials, the geometric characteristics of the cross-sections of the channels by computer modeling with visualization of the determined stresses and critical zones in the spars. The study of loads on the frame was carried out according to the methodology of determining the static load on the frame of a stationary car from the sprung masses of hinged units and aggregates, which is then multiplied by the dynamism coefficient, which takes into account the increase in the load on the frame depending on road conditions and the speed of the car. The stress distribution in the frame spars was determined according to the IV theory of strength (ac-cording to Mises). Conclusions were made about the expediency of using lightweight cold-bent channels made of high-strength steel for the manufacture of frame spars of KrAZ heavy-duty trucks, as a result of which the strength and reliability of the frames is ensured with a significant saving of metal. Recommendations are provided for strengthening frame spars in critical areas. Research results can be applied to all models of KrAZ trucks. Keywords: truck, vehicle supporting system, frame strength, frame spars, channel profile, low-alloy steel, spar stress, spar deflection.