JUSTIFICATION OF DESIGNS TO INCREASE THE BEARING

Domestic and international experience in increasing the bearing structure rigidity of vehicle bodies in the form of a reinforced shell with a cut-out is analyzed. Based on the analysis, approaches related to the reinforcement of the car underframe with additional longitudinal elements and bearing partitions are considered as promising. Options for installing one as well as with two partitions connected by longitudinal elements are considered. The first frequency of the body bending vibrations, the maximum stresses acting in the reinforced part of the structure, as well as the amount of mass gain associated with reinforcements are accepted as the criteria for choosing a rational design to increase the rigidity of the body bearing structure. The study object is the bearing structure of the sleeping passenger car body, 61-4517 model, produced by Tver Car Building Plant. Having analyzed the bearing structure of the car body, four variants of reinforcing the bearing system are proposed. For each of them, from four to ten structural designs are considered, differing in the type of profiles for their formation. The efficiency analysis within the accepted criteria is carried out by computer simulations using modern industrial software systems based on the finite element method. A detailed spatial and plate body model based on finite element is developed. Heavy equipment is included as some finite elements, as well as interior designs of the passenger car. The results obtained using the developed model are verified by the data of bench full-scale tests of the passenger car body. For each variant and design, the values of the first natural frequency of the body bending vibrations, maximum stresses arising in the structure under the action of regulatory forces, as well as the value of the mass gain of the bearing structure are obtained. The analysis of the obtained variants made it possible to find out the rational variant and its design, which provides an increase in the rigidity of the body bearing structure, a reduction in operating stresses with a minimal increase in the mass of the metal structure.