• Title, Summary, Keyword: Snap-through

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Chaotic Responses of Curved Plate under Sinusoidal Loading

  • W.Y. Poon;C.F. Ng;Lee, Y.Y.
    • Journal of Mechanical Science and Technology
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    • v.17 no.1
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    • pp.85-96
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    • 2003
  • In the present investigation, the nonlinear dynamic buckling of a curved plate subjected to sinusoidal loading is examined. By the theoretical analyses, a highly nonlinear snap-through motion of a clamped-free-clamped-free plate and its effect on the overall vibration response are investigated. The problem is reduced to that of a single degree of freedom system with the Rayleigh-Ritz procedure. The resulting nonlinear governing equation is solved using Runge-Kutta (RK-4) numerical integration method. The snap-through boundaries, which vary with different damping coefficient and linear circular frequency of the flat plate are studied and given in terms of force and displacement. The relationships between static and dynamic responses at the start of a snap-through motion are also predicted. The analysis brings out various characteristic features of the phenomenon, i.e. 1) small oscillation about the buckled position-softening spring type motion, 2) chaotic motion of intermittent snap-through, and 3) large oscillation of continuous snap-through motion crossing the two buckled positions-hardening spring type. The responses of buckled plate were found to be greatly affected by the snap-through motion. Therefore, better understanding of the snap-through motion is needed to predict the full dynamic response of a curved plate.

Snap-through Dynamics of Curved Cantilever IPMC Actuator (곡률을 갖는 캔틸레버 IPMC 작동기의 스냅-스루 동적 특성)

  • Jeon, Jin-Han;Park, Joong-Woo;Yeom, Seong-Won;Oh, Il-Kwon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.372-373
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    • 2008
  • The snap-through phenomena of the curved IPMC actuators were investigated according to the initial curvature of the actuators. The curved actuators were fabricated by long time thermal treatments. Cantilevered IPMCs have a constant curvature and their initial tip-displacements are 0, 8, and 16mm, respectively. These actuators were tested in terms of f response. AC response, FRF test for evaluating the effect of initial shape. The hysteresis and instant speed of tip point were measured for observation of the snap-through. Present results show that initial deformation strongly affects the snap-through phenomena, resulting in much larger tip-displacements.

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Nonlinear analysis of thin shallow arches subject to snap-through using truss models

  • Xenidis, H.;Morfidis, K.;Papadopoulos, P.G.
    • Structural Engineering and Mechanics
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    • v.45 no.4
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    • pp.521-542
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    • 2013
  • In this study a truss model is used for the geometrically nonlinear static and dynamic analysis of a thin shallow arch subject to snap-through. Thanks to the very simple geometry of a truss, the equilibrium conditions can be easily written and the global stiffness matrix can be easily updated with respect to the deformed structure, within each step of the analysis. A very coarse discretization is applied; so, in a very simple way, the high frequency modes are suppressed from the beginning and there is no need to develop a complicated reduced-order technique. Two short computer programs have been developed for the geometrically nonlinear static analysis by displacement control of a plane truss model of a structure as well as for its dynamic analysis by the step-by-step time integration algorithm of trapezoidal rule, combined with a predictor-corrector technique. These two short, fully documented computer programs are applied on the geometrically nonlinear static and dynamic analysis of a specific thin shallow arch subject to snap-through.

Thermopiezoelastic Nonlinear Dynamic Characteristics of Piezolaminated Plates (압전적층판의 열-압전-탄성 동적 비선형 작동특성)

  • Oh, Il-Kwon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.662-667
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    • 2005
  • Nonlinear dynamics of active piezolaminated plates are investigated with respect to the thermopiezoelastic behaviors. For largely deformed structures with small strain, the incremental total Lagrangian formulation is presented based on the virtual work principles. A multi field layer wise finite shell element is proposed for assuring high accuracy and non-linearity of displacement, electric and thermal fields. For dynamic consideration of thermopiezoelastic snap through phenomena, the implicit Newmark's scheme with the Newton-Raphson iteration is implemented for the transient response of various piezolaminated models with symmetric or eccentric active layers. The bifurcate thermal buckling of symmetric structural models is first investigated and the characteristics of piezoelectric active responses are studied for finding snap through piezoelectric potentials and the load path tracking map. The thermoelastic stable and unstable postbuckling, thermopiezoelastic snap through phenomena with several attractors are proved using the nonlinear time responses for various initial conditions and damping loss factors. Present results show that thermopiezoelastic snap through phenomena can result in the difficulty of buckling and postbuckling control of intelligent structures.

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Nonlinear analysis using load-displacement control

  • Kwon, Young-Doo;Kwon, Hyun-Wook;Lim, Beom-Soo
    • Structural Engineering and Mechanics
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    • v.19 no.2
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    • pp.153-172
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    • 2005
  • A new load/displacement parameter method is proposed for the simultaneous control of applied loads and structural displacements at one or more points. The procedure is based on a generalized Riks' method, which utilizes load/displacement parameters as scaling factors to analyze post-buckling phenomena including snap-through or snap-back. The convergence characteristics are improved by employing new relaxation factors through an incremental displacement parameter, particularly in a region that exhibits severe numerical instability. The improved performance is illustrated by means of a numerical example.

Nonlinear Analysis Method by the Arc Length Method (Arc Length Method에 의한 비선형 문제의 해법)

  • 이대희;최종근
    • Computational Structural Engineering
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    • v.9 no.3
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    • pp.107-114
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    • 1996
  • The performance for the algorithm of the arc length method has been examined in terms of the choice of the tangential stiffness matrix through the analysis for the snap buckling phenomenon of the arch beam. The curved beam element with 2 nodes including shear effect has been formed by strain element technique and then it has been used in this nonlinear analysis. Snap-through characteristics has been examined with respect to the ratios of the arch beam length to hight.

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Thermopiezoelastic Nonlinear Dynamic Characteristics of Piezolaminated Plates (압전적층판의 열-압전-탄성 동적 비선형 작동특성)

  • Oh, Il-Kwon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.7
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    • pp.836-842
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    • 2005
  • Nonlinear dynamic characteristics of active piezolaminated plates are investigated with respect to the thermopiezoelastic behaviors. For largely deformed structures with small strain, the incremental total Lagrangian formulation is presented based on the virtual work principles. A multi-field layer-wise finite shell element is proposed for assuring high accuracy and non-linearity of displacement, electric and thermal fields. For dynamic consideration of thermopiezoelastic snap-through phenomena, the implicit Newmark's scheme with the Newton-Raphson iteration is implemented for the transient response of various piezolaminated models with symmetric or eccentric active layers. The bifurcate thermal buckling of symmetric structural models is first investigated and the characteristics of piezoelectric active responses are studied for finding snap-through piezoelectric potentials and the load-path tracking map. The thermoelastic stable and unstable postbuckling, thermopiezoelastic snap-through phenomena with several attractors are proved using the nonlinear time responses for various initial conditions and damping loss factors. Present results show that thermopiezoelastic snap-through phenomena can result in the difficulty of buckling and postbuckling control of intelligent structures.

Exogenous Nitric Oxide Donation During In Vitro Maturation Improves Embryonic Development after Parthenogenesis and Somatic Cell Nuclear Transfer in Pigs

  • Elahi, Fazle;Shin, Hyeji;Lee, Joohyeong;Lee, Seung Tae;Lee, Geun-Shik;Lee, Eunsong
    • Journal of Embryo Transfer
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    • v.33 no.4
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    • pp.211-220
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    • 2018
  • Nitric oxide (NO) has an important role in oocyte maturation and embryonic development in mammals. This study examined the effect of exogenous NO donor S-nitroso-N-acetylpenicillamine (SNAP) in a maturation medium on meiotic progression and embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. When oocytes were exposed to $0.1{\mu}M$ SNAP for first 22 h of in vitro maturation (IVM) in Experiment 1, SNAP significantly improved blastocyst development in both defined and standard follicular fluid-supplemented media compared to untreated control (48.4 vs. 31.7-42.5%). SNAP treatment significantly arrested meiotic progression of oocytes at the germinal vesicle stage at 11 h of IVM (61.2 vs. 38.7%). However, there was no effect on meiotic progression at 22 h of IVM (Experiment 2). In Experiment 3, when oocytes were treated with SNAP at 0.001, 0.1 and $10{\mu}M$ during the first 22 h of IVM to determine a suitable concentration, $0.1{\mu}M$ SNAP (54.2%) exhibited a higher blastocyst formation than 0 and $10{\mu}M$ SNAP (36.6 and 36.6%, respectively). Time-dependent effect of SNAP treatment was evaluated in Experiment 4. It was observed that SNAP treatment for the first 22 h of IVM significantly increased blastocyst formation compared to no treatment (57.1% vs. 46.2%). Antioxidant effect of SNAP was compared with that of cysteine. SNAP treatment significantly improved embryonic development to the blastocyst stage (49.1-51.5% vs. 34.4-37.5%) irrespective of the presence or absence of cysteine (Experiment 5). Moreover, SNAP significantly increased glutathione (GSH) content and inversely decreased the reactive oxygen species (ROS) level and mitochondrial oxidative activity in IVM oocytes. SNAP treatment during IVM showed a stimulating effect on in vitro development of SCNT embryos (Experiment 7). These results demonstrates that SNAP improves developmental competence of PA and SCNT embryos probably by maintaining the redox homeostasis through increasing GSH content and mitochondrial quality and decreasing ROS in IVM oocytes.

Snap-through Phenomena on Nonlinear Thermopeizoelastic Behavior of Piezolaminated Plates (압전적층판의 비선형 열압전탄성 거동에서의 스냅-스루 현상)

  • Oh, Il-Kwon;Lee, In
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.232-237
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    • 2000
  • Thermopiezoelastic snap-through phenomena of piezolaminated plates are numerically investigated by applying a cylindrical arc-length scheme to Newton-Raphson method. Based on the layerwise displacement theory and von-Karman strain-displacement relationships, nonlinear finite element formulations are derived for thermopiezoelastic composite plates. From the static and dynamic viewpoint, nonlinear thermopiezoelastic behavior and vibration characteristics are studied for symmetric and eccentric structural models with various piezoelectric actuation modes. Present results show the possibility to enhance the performance of thermal structures using piezoelectric actuators and report new phenomena, namely thermopiezoelastic snapping, induced by the excessive piezoelectric actuation in the active suppression of thermally buckled large deflection of piezolaminated plates.

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A Study on the Snap-through Behaviour According to the Initial Deflection Shape of Plate Members (초기처짐형상에 따른 판부재의 천이거동에 관한 연구)

  • 고재용;이계희;박주신
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.348-356
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    • 2003
  • Recently, the buckling is easy to happen a thin plate and High Tensile Steel is used at the steel structure and marine structure so that it is wide. Especially, the post-buckling is becoming important design criteria in the ship structure to use especially the High Tensile Steel. Consequently, it is important that we grasp the conduct post-buckling behaviour accurately at the stability of the ship structure or marine structure. In this study, examined closely about conduct and snap-through behaviour after initial buckling of thin plate structure which apply compressive load according to various kinds initial deflection shape under all edges simply supported condition that make by buckling formula in each payment in advance rule to place which is representative construction of hull. Analysis method is F.E.M in used ANSYS program and complicated nonlinear behaviour to analyze such as secondary buckling with snap-through behaviour. Nonlinear buckling control is applied between newton-raphson method and arc-length method in this study

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