Modal Analysis and Vibration Mitigation of Twin Bus Seat with Passive Leg Isolation

This paper presents an integrated experimental and numerical investigation of the vibration characteristics and mitigation strategies for a twin bus seat structure. Experimental Modal Analysis (EMA) was performed using a roving hammer technique and triaxial accelerometers to identify the natural frequencies and mode shapes. A Finite Element Analysis (FEA) model developed in ANSYS was then correlated with the experimental results, confirming strong agreement in both frequency values and mode shapes. Vibration transmissibility tests using an electromagnetic shaker further evaluated the performance of rubber isolators mounted at the seat legs, revealing significant improvements in attenuation at mid-to-high frequency ranges. Three different damper types were assessed, and the most effective configuration achieved a vibration reduction of approximately 33%. Finally, an objective function was formulated based on transmissibility data to enable Particle Swarm Optimization (PSO) of isolator parameters, establishing a foundation for cost-effective vibration mitigation without structural modification. The findings provide valuable insights for improving passenger comfort and structural integrity in public transport seating systems.