Performance Analysis of Suspension Seats under High Magnitude Vibration Excitations: Part 1: Model Development and Validation

Abstract

Performance analyses of suspension seats subject to high magnitude excitations require particular modeling considerations associated with impacts against the motion limiting elastic buffers, possible loss of contact between the seat and the occupant, and component characterization over a wide range of inputs. In this study, three different suspension seats are considered to formulate a generalized model that would be applicable under low to high magnitude excitations. The static and dynamic characteristics are evaluated in the laboratory under a wide range of excitations and seat preloads. General model structures are proposed to characterize the components of the selected suspension seats as functions of the preload and nature of excitation. A general model for the suspension seats is formulated upon integration of the component models and consideration of the potential body-hop motions. The validity of the proposed model is examined under a number of excitations representing continuous random vibration environment of different vehicles, such as urban buses and class-1 construction machinery (EM1), and transient sprung mass oscillations in the vicinity of the suspension seat natural frequency. The validity of the model is further examined for all three seats subject to amplified excitations of the urban buses and the construction machinery. The results of the study suggest that the proposed model can be effectively applied to assess the suspension performance under high magnitude excitations that induce repetitive impacts with motion limiting buffers. The influences of various design parameters on the shock and vibration isolation performance of the selected suspension seats are presented in the second part of this work.