Nonlinear Dynamic Modelling of a Suspension Seat for Predicting the Vertical Seat Transmissibility

Weitan Yin,Yi Qiu,Juyue Ding,Mauro Gaggero

doi:10.1155/2021/3026108

Abstract

Suspension seats are widely used in heavy vehicles to reduce vibration transmitted to human body and promote ride comfort. Previous studies have shown that the dynamics of the suspension seat exhibits nonlinear behaviour with changed vibration magnitudes. Despite various linear seat models developed in the past, a nonlinear model of the suspension seat capturing the nonlinear dynamic behaviour of the seat suspension and cushion has not been developed for the prediction of the seat transmissibility. This paper proposes a nonlinear lumped parameter model of the suspension seat to predict the nonlinear dynamic response of the seat. The suspension seat model comprises of a nonlinear suspension submodel integrated with a nonlinear cushion submodel. The parameters of the submodels are determined by minimizing the error between the simulated and the measured transmissibility of the suspension mechanism and the force-deflection curve of the seat cushion, respectively. The model of the complete seat is then validated using the seat transmissibility measured with inert mass under vertical vibration excitation. The results show that the proposed suspension seat model can be used to predict the seat transmissibility with various excitation magnitudes.

Highlights

A suspension seat generally comprises two parts that play the most important role in the transmission of the Whole-Body Vibration (WBV): the suspension mechanism and the seat cushion. e dynamic performance of the suspension seat depends on the dynamic properties of both parts
It was found in a laboratory study that when the magnitude of the vibration excitation was low, the suspension mechanism tended to act as if it was locked up by friction, and the seat transmissibility was mainly affected by the dynamic characteristics of the seat cushion, whereas when subjected to higher magnitudes of excitation, the dynamic performance of the suspension seat was dominated by the dynamics of the suspension rather than the seat cushion [6]
With the increase of the excitation magnitude, the primary resonance frequency of the transmissibility of the suspension mechanism or the complete seat tended to decrease [6]. e seat cushion in modern vehicles is normally made of Mathematical Problems in Engineering polyurethane foam, which exhibits nonlinear behaviour that can be affected by the magnitudes of excitation [7]

Summary

Introduction

A suspension seat generally comprises two parts that play the most important role in the transmission of the WBV: the suspension mechanism and the seat cushion. e dynamic performance of the suspension seat depends on the dynamic properties of both parts. Zhou et al [16] developed a model of the suspension seat consisting of nonlinear spring and damper of the suspension mechanism, and Zhao et al [17] developed a nonlinear suspension seat with rubber spring For both models, the predicted vibration exposure and seat transmissibility matched well with the measured counterparts, while the prediction under other conditions using the same set of parameter values was not reported in these studies. From the review of the previous studies, it is found that a model of suspension seat has not been reported, which covers the nonlinear dynamic behaviour of both the suspension mechanism and the seat cushion at different excitation magnitudes with just one set of parameter values and is capable of giving satisfactory and validated prediction of the transmissibility of the suspension seat under various excitations.

Methods

Discussion

Conclusion