MODEL-BASED FINITE ELEMENT ANALYSIS OF THE RESONANT SYSTEM IN RAILWAY SECONDARY SUSPENSION APPLICATIONS

Abstract

As the global demand for modern railway transportation grows, there is an increasing need to monitor and control systems within railway vehicles to accommodate the rising number of passengers. These advanced systems are essential for enhancing performance, safety, comfort, and cost efficiency. To meet these evolving demands, it has become crucial to focus on the study of air springs, which are widely used as the secondary suspension system in most railroad vehicles. Air springs have largely replaced traditional coil steel springs due to their numerous advantages, particularly in terms of vehicle dynamics. The suspension system plays a vital role in maintaining ride quality and track-holding performance, especially at high driving speeds. In this context, active suspension systems have emerged as highly capable technologies, addressing the new demands for better ride comfort, higher speeds, and lower maintenance costs in railway vehicles. Ride quality is a key metric that refers to the suspension system's ability to minimize undesired disturbances, keeping them within a range that ensures human comfort and the safety of the car body. Air springs, as the main component of the secondary suspension system, provide both stiffness and damping between the bogie and the car body, which significantly impacts the overall comfort of the railway vehicle. Given the importance of air springs, it is essential to model and analyze their behavior under different working conditions to understand how their performance can be optimized. This study focuses on a detailed examination of the ride comfort and ride quality attributes associated with a railway vehicle, with particular attention to a secondary suspension system that utilizes a laminated rubber base isolator. To support this investigation, a sophisticated 3-D dynamic model of the railway vehicle was developed, encompassing 13 degrees of freedom. This dynamic model was specifically designed to simulate the behavior of the air suspension system in both its inflated and deflated states. The study's findings reveal that during the inflated state of the air spring, railway vehicles exhibit a high level of comfort and ride quality, particularly at speeds up to 160 km/h. The performance remains satisfactory in the range of 160 to 220 km/h, although the comfort levels are starting to decline. Importantly, when the air spring is deflated, the dynamic performance of the vehicle does not significantly deteriorate within the safety limits during high-speed operations.