Numerical Simulation of Primary Suspension in FIAT Bogie for Vertical Excitation

In India, the prime mode of long transport for passengers and freight is Indian railways which use ICF and LHB coaches. LHB coaches which use FIAT bogie are superior to ICF coaches due to their higher carrying capacity and being suitable for high-speed application. For comfortable and controlled ride, springs are essentials; however, due to dynamic loading, spring failures are observed. A similar type of failure is observed in outer springs of primary suspension in FIAT bogie during maintenance in Indian railways. To calculate dynamic deflection of spring, 4 DOF equivalent spring mass damper system is modelled and required technical data is collected from Indian railway publications and research papers. The state space approach is used to check the controllability of the system, and the system is found to be continuous and controllable. By considering track excitation, it is found that spring has static deflection 92.3 mm and 14 mm of dynamic deflection which can lead to dynamic failure.