Measurement and Analysis of Vibration Transmissibility through Tractor Seat

Abstract: Tractor drivers often exposed to high-amplitude and low frequency vibrations that could impact the ride comfort. Tractor-terrain interaction emits vibrations that transmitted to the driver’s body through the seat-pan, mainly. In present study, the vibration transmissibility response (i.e. from the seat base to seat pan location) has been evaluated using Finite Element Method (FEM). Three dimensional model of the tractor seat was designed by considering the various seat elements (i.e. frame, sub-frame, cushion, Swing-arm, spring, damper, and roller) and their material properties (i.e. Density, Young’s modulus, Poisson’s Ratio) in SoildWorks 2014. Three different types of seat suspension systems of varying spring stiffness (0.3 kg/mm; 0.55 kg/mm; and 0.7 kg/mm) with damping coefficient of 1465.9 Ns/m has been considered to analyze transmissibility response. Seat cushion of Polyurethane (PU) light foam material with thickness of 54 mm; density of 68 kg/m³, seat backrest inclination of 12º with cushion thickness of 45 mm has been set uniform throughout the investigation. Vibration transmissibility responses were analyzed within the frequency range of 0-20 Hz at 0.5 m/s2 along the vertical direction. Tractor seat found to exhibit maximum transmissibility between 2 to 6 Hz frequency ranges. In addition, the seat suspension with spring stiffness of 0.55 kg/mm showed approximately 16% minimum vibration transmissibility compared to other suspension systems. In conclusion, the dominant frequency ranges found in the vicinity of natural frequency of various human body parts that may impact the ride comfort; and the spring stiffness has considerable effect on the vibration transmissibility.

Keywords: Vibration, Seat Dynamics, Ride Comfort, Taguchi's Method

DOI: 10.54941/ahfe1002469

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