• Title/Summary/Keyword: indirect snapping

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Analysis of Dynamic Instability Characteristic of EP Shell Structures under Sinusoidal Excitations (정현파 하중을 받는 EP(Elliptic Paraboliodal)쉘 구조물의 동적 불안정 특성 분석)

  • Kim, Seung-Deog;Kim, Doo-Ri
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.1
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    • pp.127-134
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    • 2010
  • The dynamic instability for snapping phenomena has been studied by many researchers. Few paper deal with the dynamic bucking under the load with periodic characteristics, and the behavior under periodic excitation is expected the different behavior against STEP excitation. We investigate the fundamental mechanisms of dynamic instability when shallow EP(Elliptic Paraboliodal) shell of two degree of freedom are subjected to sinusoidal excitation with direct snapping and indirect snapping. By using Newmark-$\beta$ method, we can get the nonlinear response, and characteristics of the dynamic instability through the running response spectrum by FFT(fast Fourier Transform) and attractors are compared in the phase plane. Dynamic buckling loads are strongly influenced by the relationships between the natural frequency of structures and the dominant frequency of incident excitations.

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Instability Characteristic of Nonlinear Running Spectra of Shallow EP Shells under STEP Excitations (스텝 하중을 받는 얕은 EP쉘 구조물의 비선형 연속응답스펙트럼에 의한 불안정 특성)

  • Kim, Seung-Deog;Kim, Doo-Ri
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.1
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    • pp.119-126
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    • 2010
  • The some papers which deal with the dynamic instability for shell-like structures under the dynamic excitation have been published, but there are few papers which treat the essential phenomenon of the dynamic buckling using the phase plane for investigating occurrence of chaos. In nonlinear dynamic, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and indirect snapping of shallow EP shell considering geometrical nonlinearity are investigated by Galerkin method numerically. This finding out the characteristic of the dynamic instability through the phases curves and running response spectrum.

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Buckling Characteristics of Shallow Sinusoidal Arches by Nonlinear Eigenvalue Analysis (비선형 고유치 해석에 의한 정현형 아치의 좌굴 특성에 관한 연구)

  • 윤태영;김승덕
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.10a
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    • pp.185-192
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    • 2002
  • In this study, we choose the sinusoidal shaped arch with pin-ends subjected to sinusoidal distributed excitation to investigate the fundamental mechanism of the dynamic instability. We derive the nonlinear equations of motion to investigate the instability phenomenon of arch structures and Identify the buckling characteristics of sinusoidal shaped arch structures through the nonlinear eigenvalue analysis with discreted equations of motion by Galerkin's method. We examine that phenomenons which direct snapping and indirect snapping with backbone curves to understand occurrence paths of the dynamic buckling.

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Dynamic Direct and Indirect Buckling Characteristics of Arch by Running Response Spectrum (연속 응답 스펙트럼 분석에 의한 아치의 동적 직접 및 간접 좌굴 특성)

  • Yun, Tae-Young;Kim, Seung-Deog
    • 한국공간정보시스템학회:학술대회논문집
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    • 2004.05a
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    • pp.161-168
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    • 2004
  • The dynamic instability of snapping phenomena has been studied by many researchers. Few papers deal with dynamic buckling under loads with periodic characteristics, and the behavior under periodic excitations is expected to be different from behavior under STEP excitations. We investigate the fundamental mechanisms of the dynamic instability when the sinusoidally shaped arch structures are subjected to sinusoidally distributed excitations with pin-ends. The mechanisms of dynamic indirect snapping of shallow arches are especially investigated under not only STEP function excitations but also under sinusoidal harmonic excitations, applied in the up-and-down direction. The dynamic nonlinear responses are obtained by the numerical integration of the geometrically nonlinear equation of motion, and examined by Fourier spectral analysis in order to get the frequency-dependent characteristics of the dynamic instability for various load levels.

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The Instability Behavior of Shallow Sinusoidal Arches(2) : Classification of Dynamic Buckling under Step Pressure (얕은 정현형 아치의 불안정 거동에 관한 연구(2) : 스텝하중에서의 동적좌굴 특성)

  • 김승덕;박지윤;권택진
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.12 no.3
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    • pp.417-426
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    • 1999
  • The some papers which deal with the dynamic instability for shell-like structures under the step load have been published, but there are few papers which treat the essential phenomenon of the dynamic buckling using the phase plane for investigating occurrence of chaos. In nonlinear dynamics, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and the indirect snap-buckling of shallow arches considering geometrical nonlinearity are investigated numerically and compared with the static critical load.

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Dynamic Buckling Characteristics of Arch Structures by Running Response Spectrum (연속 응답 스펙트럼 분석에 의한 아치 구조물의 동적 좌굴 특성)

  • Kim, Seung-Deog;Yun, Tae-Young
    • Journal of Korean Association for Spatial Structures
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    • v.4 no.2 s.12
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    • pp.81-88
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    • 2004
  • The dynamic instability of snapping phenomena has been studied by many researchers. Few papers deal with dynamic buckling under loads with periodic characteristics, and the behavior under periodic excitations is expected to be different from behavior under STEP excitations. We investigate the fundamental mechanisms of the dynamic instability when the sinusoidally shaped arch structures are subjected to sinusoidally distributed excitations with pin-ends. The mechanisms of dynamic indirect snapping of shallow arches are especially investigated under not only STEP function excitations but also under sinusoidal harmonic excitations, applied i the up-and-down direction. The dynamic nonlinear responses are obtained by the numerical integration of the geometrically nonlinear equation of motion. And using this analyze characteristics of the dynamic instability through the running response spectrum by FFT(Fast Fourier Transform).

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