Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam

In this paper, the characteristics and the effectiveness of a nonlinear passive vibration isolator based on a post-buckled beam is investigated experimentally. The intended application is specifically isolation in the vertical direction where the isolator is required to be sufficiently stiff statica...

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Autores principales:	Takumi SASAKI, Timothy WATERS, Yumiko TSUJI
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2015
Materias:	base isolation nonlinear isolator free vibration transmissibility quasi-zero-stiffness (qzs) Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/a8d5341d9bec455ba5758b8103cecf4f
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spelling	oai:doaj.org-article:a8d5341d9bec455ba5758b8103cecf4f2021-11-26T06:25:42ZExperimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam2187-974510.1299/mej.15-00030https://doaj.org/article/a8d5341d9bec455ba5758b8103cecf4f2015-04-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/2/3/2_15-00030/_pdf/-char/enhttps://doaj.org/toc/2187-9745In this paper, the characteristics and the effectiveness of a nonlinear passive vibration isolator based on a post-buckled beam is investigated experimentally. The intended application is specifically isolation in the vertical direction where the isolator is required to be sufficiently stiff statically to bear the weight of the isolated mass. The isolator consists of two beams joined to form an inverted L-shape and the weight of the isolated mass is taken to act at the vertex. If the weight of isolated mass is larger than the buckling load of the L-shaped beam then the beam buckles in one of two modes, one of which is unstable. In this paper, the static restoring force of the unstable mode is measured and an appropriately selected coil spring is added to counteract the negative stiffness of the beam. The resulting system presents a dramatically lower stiffness to small excursions about its equilibrium position in its buckled state but maintains its static load bearing capability. Free vibration measurements are presented which show some amplitude dependency of the natural frequency for large amplitude motion. Low amplitude harmonic base excitation measurements are also conducted from which transmissibility measurements are obtained and compared with corresponding results from a Finite Element model. The fundamental resonance is about 80% lower than that achievable by a comparable linear isolator. However the potential improvement in isolation performance has not been fully realised in the prototype design due to the presence of higher frequency internal resonances of the isolator, mitigation of which is the focus of ongoing work.Takumi SASAKITimothy WATERSYumiko TSUJIThe Japan Society of Mechanical Engineersarticlebase isolationnonlinear isolatorfree vibrationtransmissibilityquasi-zero-stiffness (qzs)Mechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 2, Iss 3, Pp 15-00030-15-00030 (2015)
institution	DOAJ
collection	DOAJ
language	EN
topic	base isolation nonlinear isolator free vibration transmissibility quasi-zero-stiffness (qzs) Mechanical engineering and machinery TJ1-1570
spellingShingle	base isolation nonlinear isolator free vibration transmissibility quasi-zero-stiffness (qzs) Mechanical engineering and machinery TJ1-1570 Takumi SASAKI Timothy WATERS Yumiko TSUJI Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
description	In this paper, the characteristics and the effectiveness of a nonlinear passive vibration isolator based on a post-buckled beam is investigated experimentally. The intended application is specifically isolation in the vertical direction where the isolator is required to be sufficiently stiff statically to bear the weight of the isolated mass. The isolator consists of two beams joined to form an inverted L-shape and the weight of the isolated mass is taken to act at the vertex. If the weight of isolated mass is larger than the buckling load of the L-shaped beam then the beam buckles in one of two modes, one of which is unstable. In this paper, the static restoring force of the unstable mode is measured and an appropriately selected coil spring is added to counteract the negative stiffness of the beam. The resulting system presents a dramatically lower stiffness to small excursions about its equilibrium position in its buckled state but maintains its static load bearing capability. Free vibration measurements are presented which show some amplitude dependency of the natural frequency for large amplitude motion. Low amplitude harmonic base excitation measurements are also conducted from which transmissibility measurements are obtained and compared with corresponding results from a Finite Element model. The fundamental resonance is about 80% lower than that achievable by a comparable linear isolator. However the potential improvement in isolation performance has not been fully realised in the prototype design due to the presence of higher frequency internal resonances of the isolator, mitigation of which is the focus of ongoing work.
format	article
author	Takumi SASAKI Timothy WATERS Yumiko TSUJI
author_facet	Takumi SASAKI Timothy WATERS Yumiko TSUJI
author_sort	Takumi SASAKI
title	Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
title_short	Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
title_full	Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
title_fullStr	Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
title_full_unstemmed	Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam
title_sort	experimental study on a nonlinear vibration isolator based on a post-buckled inverted l-shaped beam
publisher	The Japan Society of Mechanical Engineers
publishDate	2015
url	https://doaj.org/article/a8d5341d9bec455ba5758b8103cecf4f
work_keys_str_mv	AT takumisasaki experimentalstudyonanonlinearvibrationisolatorbasedonapostbuckledinvertedlshapedbeam AT timothywaters experimentalstudyonanonlinearvibrationisolatorbasedonapostbuckledinvertedlshapedbeam AT yumikotsuji experimentalstudyonanonlinearvibrationisolatorbasedonapostbuckledinvertedlshapedbeam
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Experimental study on a nonlinear vibration isolator based on a post-buckled inverted L-shaped beam

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