КОНЦЕПЦІЯ ОПТИМІЗАЦІЇГЕОМЕТРІЇ НАДРЕСОРНОЇ БАЛКИ ЗАЛІЗНИЧНОГО ВІЗКА ЗА КРИТЕРІЄММІНІМІЗАЦІЇ МАСИ

To develop a concept for optimizing the geometry of a bogie bolster (transom) that minimizes structural mass while guaranteeing compliance with the normative safety factor, overcoming the limitations of traditional design methods based on static schemes, which cause uneven metal distribution and excessive mass. Methodology. A comprehensive theoretical-numerical approach was applied. The spectrum of operational loads was formed using methods of mathematical statistics and the theory of random processes. The stress-strain state was calculated using the finite element method. Topological optimization was implemented using the SIMP method in an inverse formulation: mass minimization subject to a direct stress constraint and a differentiated safety factor for the operating modes, with stress aggregation via the P-norm and density updating by algorithm. Three concepts were compared: stiffness- constrained (A), rib-based redistribution (B), and a hybrid fatigue-aware approach (C). Results. The baseline analysis showed that over 62 % of the bolster’s volume operates at stresses below 30 MPa, indicating a reserve for mass reduction. Approach A reduced mass by 12–15 % but had the lowest fatigue safety margin; Approach B provided the highest safety factor (ns = 1.74) with only a 5.7 % mass reduction; the hybrid Approach C proved the most balanced – an 18 % mass reduction, ns = 1.62 (≥1.5), and the greatest service life (62.1 · 106 cycles). Scientific novelty. For the first time, the mass-minimization problem was formulated as an inverse SIMP topological optimization problem with an explicit, differentiated constraint on the normative safety factor across three operating modes, integrating the probabilistic load spectrum directly into the objective function and combining mass, stiffness, and fatigue criteria within a single hybrid formulation. Practical significance. Preliminary calculations demonstrated that implementing the proposed concept allows the bolster’s mass to be reduced by 18 % without violating strength requirements, reducing the bogie’s material consumption while preserving casting manufacturability and interchangeability with parts of the current fleet.