Prediction of Ply Angles of Air Springs According to Airbag Positions and Their Effects on Lateral and Torsional Stiffness

Abstract

The stiffness in various directions of air springs have a great influence on the stability of high-speed trains. Due to the change in the bogie structure, the required functions of the air springs have also diversified, and the damping of various loading modes such as vertical, lateral, and torsional movements is emerging as important. The stiffnesses are affected by the shape of the air bag, the material, and the ply angles. In this paper, the relationship between the ply angle and the radial position is proposed by equations from deformation modes. The variable angles in the plies were compared and demonstrated in air-spring analysis using the rebar elements. The vertical, lateral, and torsional stiffness of air springs without auxiliary springs were compared between constant ply angles and variable ply angles with respect to the positions. When mainly dealing with the vertical stiffness, the effect of the angle variation was small; however, it was found that it had a large effect of more than 24% and 30% on the stiffness in the lateral direction and torsional direction, respectively.