1401 Fundamental Study of Vibration Reduction of Railway Vehicle Carbody Utilizing Arbitrary-Shaped Elastic Body

In automatic transmissions for cars, a damper is installed in the lock-up clutch to absorb torsional vibrations caused by combustion in the engine. Although a damper with low stiffness reduces the torsional vibration, low-stiffness springs are difficult to use because of space limitations. To address this problem, dampers have been designed using a piecewise-linear spring having three different stages of stiffness. However, a nonlinear subharmonic vibration of order 1/2 occurs because of the nonlinearity of the piecewise-linear spring in the damper. In this study, we experimentally and analytically examined a countermeasure against the subharmonic vibration by increasing the stages of the piecewise-linear spring using the one-degree-of-freedom system model. We found that the gap between the switching points of the piecewise-linear spring was the key to vibration reduction. The experimental results agreed with results of the numerical analyses.

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435 Vibration Reduction of Flexural Vibration of Railway Vehicle Carbodies with High-damping Elastic Support of Underfloor Equipments

The Proceedings of the Dynamics & Design Conference ◽

10.1299/jsmedmc.2011._435-1_ ◽

2011 ◽

Vol 2011 (0) ◽

pp. _435-1_-_435-10_

Author(s):

Takahiro TOMIOKA ◽

Tadao TAKIGAMI ◽

Ken-Ichiro AIDA

Keyword(s):

Vibration Reduction ◽

Flexural Vibration ◽

Elastic Support ◽

Railway Vehicle

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Multimodal Reduction of Elastic Vibrations in Plate Structure using Super Absorbent Polymer Beads

EPI International Journal of Engineering ◽

10.25042/epi-ije.022020.03 ◽

2020 ◽

Vol 3 (1) ◽

pp. 21-29

Author(s):

Takahiro Tomioka ◽

Karen Minamisawa

Keyword(s):

Vibration Reduction ◽

Basic Mechanism ◽

Vibration Measurement ◽

Scale Model ◽

Railway Vehicle ◽

Polymer Beads ◽

Super Absorbent Polymer ◽

Elastic Vibrations ◽

Reduction Effect ◽

Absorbent Polymer

This paper deals with multimodal reduction of structural elastic vibrations. Super absorbent polymer beads (SAP beads) have been introduced as a simple damping device inspired by the multimodal vibration reduction effect by passengers on railway vehicles. A series of vibration measurement tests using a 1:10 scale model of railway vehicle floor structure (model underframe) was carried out. The SAP beads which are sold commonly as water retention agent were stacked in a container and applied to the model underframe. From the experiments, multimodal vibration reduction effects have been demonstrated. A drastic difference has been observed when water was added together with SAP beads. To investigate the basic mechanism of the damping effect obtained by the experiments, an analytical model, which consists of multiple masses that are supported at an angle to each other, and its simplified model was proposed and numerical studies were conducted. Some specific combinations of the mass, spring, and damping elements in the model could express the experimental results well, and it has been estimated from the numerical results that each SAP layer act as an un-uniform subsystem.

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