Vibration isolation in neonatal transport by using a quasi-zero-stiffness isolator

Abstract

New-born infants are likely to suffer excessive vibration during neonatal transport, but there is no effective method to attenuate the transmission of vibration from the ambulance floor to an infant. This would be particularly detrimental to premature or sick new-born babies. In this paper, a quasi-zero-stiffness (QZS) vibration isolation method is proposed to improve the comfort of the infant in an incubator. The infant compartment is supported by quasi-zero-stiffness isolators, which are realized each by combining a pair of mutually repelling permanent magnets in parallel connection with a coil spring, and their parameters are obtained by design optimization to maximize the displacement range with smaller stiffness than that of the coil spring. A lumped-mass model of the transport incubator is developed, and the vibration isolation performance is estimated in terms of displacement and acceleration transmissibility. Numerical results reveal that a comparatively heavy damping is needed to completely avoid the jump phenomenon inherent in polynomial nonlinearity and suppress resonance, and thus achieve smooth and effective vibration attenuation starting from an ultra-low frequency. Under a random disturbance, magnification of vibration is observed in the original transport incubator, but notable attenuations of root mean square (RMS) acceleration and displacement in the modified one, which indicates that the proposed quasi-zero-stiffness isolator should be a good solution to eliminate vibration-induced injuries in neonatal transport.

A novel integrated quasi-zero stiffness vibration isolator for coupled translational and rotational vibrations

“…Compared to one-DOF QZS isolators proposed for practical engineering applications, such as vehicle seat [35] and transport incubator [36] , an integrated translational-rotational QZS vibration isolator is proposed in this paper to isolate the vibrations in two directions simultaneously. The high-static-low-dynamic stiffness characteristics can be provided in two DOFs, not only in the translational direction, but also in the rotational direction.…”

Enhanced ride comfort using nonlinear seat suspension with high-static-low-dynamic stiffness

“…However, the vehicle ride comfort under shock and random excitations induced by uneven road profiles was not investigated. Recently, Zhou et al 20 proposed a QZS suspension and applied it to neonatal transport. But only 2 DOFs were considered.…”

Beneficial performance of a quasi-zero stiffness vibration isolator with generalized geometric nonlinear damping

“…Then Liu et al 7,8 proposed a QZS vibration isolator using Euler buckled beams as the stiffness corrector and investigated its dynamic characteristics and isolation performance by experiment. Zhou et al 9 further applied a QZS suspension system to the neonatal transport to protect new-born infants using two ring magnets as the stiffness corrector. In addition to isolating translational motion, Zheng et al 10 developed a QZS torsional vibration isolator using a torsion magnetic spring as the stiffness corrector and conducted parametric analysis on the isolation performance.…”