Railway Track Ballast Layer Stiffness Dynamic Control Elastic-Linear Model

Abstract

The paper presents the results of mathematical modeling of the shock-elastic interaction process in the dynamic densimeter for dynamic control of the ballast layer of the railroad track. The installation is used to determine the compaction level and to estimate the carrying capacity of the ballast layer during the inter-repair period of tampering, renewal and track stabilization operations. The effect of exposure on the controlled elastic base is considered within a four-element mathematical model. The time intervals of interaction between the model elements are revealed. Each time interval is described by a system of second-order differential equations, for which analytical solutions were obtained. The model verification was evaluated during tests with a dynamic control unit consisting of a loading plate, a falling weight, and an elastic-damping element located between the weight and the loading plate. Tests were conducted on a polyurethane surface with known stiffness. In the process, signals of vertical acceleration of the loading plate when the load strikes the elastic-damping element were recorded. The acceleration was recorded by an accelerometer sensor with a sampling rate of 42 kHz being connected to a computer with specialized software. The acceleration data were obtained for different values of the stiffness of the elastic-damping element in the installation. To evaluate the simulation results, the obtained signals were compared with the theoretical model by the correlation method. According to the results of modeling, the main amplitude and time informative parameters used to determine the degree of compaction of the base layer have been singled out. The dependence of the values of informative parameters on the installation parameters (load weight, loading plate weight, stiffness of an elastic-damping element) in conditions of uncertainty was studied. The obtained dependences are used to estimate the error of each parameter in calculating the rigidity of the base. Informative parameters have been determined that allow you to determine the stiffness of the base with an error of not more than 7%. A method for selecting the optimal characteristics of the unit design and informative parameters to ensure minimum errors has been developed.