Finite element analysis of the span structures dynamics under a moving load influence

Abstract

Introduction: Providing the span structure durability under dynamic influences is one of the main tasks in their design and construction. This task is accomplished mainly by studying the dynamic behavior of railway bridges when a train is moving. The paper considers the study of building a span structure finite element model under dynamic influences caused by a moving load on the main beam of railway bridge crossings. Methods: Construction members are designed by the finite element method in the Midas civil software package using rod finite elements. The dynamical analysis is carried out by the direct dynamic method in a linear setting. Fixed loads on the structure are transferred to the mass to meet the requirements of dynamic analysis. The rail is designed as a linear elastic Bernoulli-Euler beam of finite length, and the bridge is designed as a series of multi-span continuous Bernoulli-Euler beams. The interaction of the system (train — track — bridge) is designed by elastic elements. Results: An algorithm for calculating span structures under dynamic influences was created and a dynamic response of the structure was built. As a result of all the above, the dependences of the greatest vertical dynamic displacement and dynamic acceleration on time for different speeds were obtained. Discussion: This work made it possible to understand the principle of creating a linear mathematical model of the dynamic interaction of the system (bridge — train — railway) by the finite element method and presented an algorithm for calculating span structures under dynamic influences. The article showed the influence of train speed on the dynamic behavior of span structures, so it is necessary to take into account this influence on the parameters of the stress-strain state (vertical displacements).