РАЗВИТИЕ МЕТОДОВ АНАЛИЗА ПРОЧНОСТИ И НАДЕЖНОСТИ НЕСУЩИХ КОНСТРУКЦИЙ ПОДВИЖНОГО СОСТАВА С ИСПОЛЬЗОВАНИЕМ МЕТОДОВ МАТЕМАТИЧЕСКОГО МОДЕЛИРОВАНИЯ

Abstract

The purpose of the work is a procedure formation for the analysis of strength and reliability of rolling-stock bearing structure using methods of mathematical modeling. Its appraisal is shown by the example of improvements in a universal gondola car bearing structure. The procedure offered is formed by a mathematical modeling of bearing structure dynamic loading in the rolling-stock operation including shunting movement encounters. At the first stage of the procedure the dynamic computer simulations of a rail crew movement on way roughness are under development. As a result of modeling there are defined dynamic loads influencing a bearing structure in operation. The analysis of the stress-strain state of the bearing structure is carried out on the basis of detailed shell finite element models. The computation is carried out in a dynamic position through the method of the direct integration of nodal-relocation equations. The estimate of bearing structures fatigue life in a pivot area was carried out on the basis of the linear hypothesis of fatigue damages summation, the power approximation of a material fatigue curve and scheming dynamic stresses affecting the structure through the method of complete cycles. 
 Within the limits of the procedure the history of loading was presented as a step function. On the basis of the results of a stress-strain state in the bearing structure of a gondola car body in a static and dynamic location there is carried out the analysis of fatigue life in a pivot area of the gondola car and the conclusions were drawn regarding crack-like defect occurrence in a center plate arrangement of a frame. 
 There are offered three versions for updating the pivot joint of a gondola car with the purpose of its fatigue life increase. For each version of updating there are developed corresponding detailed finite element models of the pivot area and on their basis the analysis of strength and fatigue life is performed. 
 On the basis of computation results and taking into account the manufacturability of center plate arrangement production an efficient version is recommended for updating a pivot joint of a gondola car. The pivot joint modernization according to the version offered allowed decreasing maximum acting stresses in the pivot joint by 27% and increasing service life of the welded joint elements up to 29 years.