• Title/Summary/Keyword: 보강 원통

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Nonlinear Buckling Characteristics of Ring-stiffened Circular Cylinders under Uniform External Pressure (균일한 외압을 받는 원환보강 원통구조의 비선형 좌굴 특성)

  • Ahn, Dang;Kim, Soo-Young;Shin, Sung-Chul;Chung, Bo-Young;Koo, Youn-Hoe
    • Journal of Ocean Engineering and Technology
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    • v.26 no.2
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    • pp.79-84
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    • 2012
  • This study aimed to analyze the nonlinear buckling of ring-stiffened circular cylinders under uniform external pressure, e.g. hydrostatic pressure, considering material nonlinearity and initial imperfection. In the present study, we analyzed the collapse pressure of pressure vessels using ANSYS Workbench, which is a framework of finite element methods. First, linear buckling analysis is performed to find collapse modes of the model. Second, scaling the first mode shape with small factor, geometric model is pre-deformed. And then, by analyzing the nonlinear buckling of the pre-deformed shape, the collapse pressure is estimated. To verify the validity of the analyses, we compared the results with Ross' experimental results. Finally, we applied it to ring-stiffened circular cylindrical shell of the pressure hull of a small submarine.

Stochastic Imperfection Sensitivity Analyses of Stiffened Cylindrical Shells with Geometric Random Imperfection (불확정적인 초기형상결함을 갖는 보강 원통형 쉘의 확률론적 초기결함 민감도해석)

  • D.K. Kim;Y.S. Yang
    • Journal of the Society of Naval Architects of Korea
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    • v.31 no.1
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    • pp.142-154
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    • 1994
  • In this paper, stochastic imperfection sensitivity analyses of stiffened cylindrical shells under static load are presented. Multimode formulation is performed for the buckling load calculation based on the Donnell's theory and Galerkin approximation. Random imperfection field theory and response surface method are combined with deterministic bucking analysis scheme to perform stochastic imperfection sensitivity analyses of stiffened cylindrical shells considering random geometric imperfection. From the characteristics of probabilistic bucking load, the relation between reliability index and safety parameter can be obtained in addition to the relation between load and reliability index. Those results can be used to determine the range of required safety parameter and acceptable imperfection.

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Characteristics of Detectors for Measurements of Photon Depth Doses in Build-Up Region (선량보강(Build-up) 영역에서의 광자선 깊이선량률 측정을 위한 검출기의 특성 비교)

  • Kang Sei-Kwon;Park Suk Won;Oh Do Hoon;Park Hee Chul;Kim Su Ssan;Bae Hoonsik;Cho Byung Chul
    • Progress in Medical Physics
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    • v.16 no.2
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    • pp.77-81
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    • 2005
  • To determine the appropriate method out of various available methods to measure build-up doses, the measurements and comparisons of depth doses of build-up region including the surface dose were executed using the Attix parallel-plate ionization chamber, the Markus chamber, a cylindrical ionization chamber, and a diode detector. Based on the measurements using the Attix chamber, discrepancies of the Markus chamber were within $2\%$ for the open field and increased up to $3.9\%$ in the case of photon beam containing the contaminant electrons. The measurements of an cylindrical ionization chamber and a diode detector accord with those of the Attix chamber within $1.5\%\;and\;1.0\%$ and after those detectors were completely immersed in the water phantom. The results suggest that the parallel-plate chamber is the best choice to measure depth doses in the build-up region containing the surface, however, using cylindrical ionization chamber or diode detector would be a reasonable choice if no special care is necessary for the exact surface dose.

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Free Vibration and Buckling Analysis of the Composite Laminated Cylindrical Shells with the Orthogonal Stiffeners (직교보강된 복합재료 원통셀의 진동 및 좌굴해석)

  • 이영신;김영완
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.04a
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    • pp.349-354
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    • 1996
  • The analytical solutions for the free vibration and buckling of cross-ply laminated composite cylindrical shell with axial stiffeners(stringers) and circumferential stiffeners(rings), that is, orthogonally stiffened shells, are presented using the energy method. The stiffeners are assumed to be an integral part of the shell and have been directly included in analysis(it's called discrete stiffener theory). The effect of the parameters such as the stacking sequences, the shell thickness, the shell length-to-radius ratio are studied. By comparison with the previously published analytical results for the stiffened cylindrical shells, it is shown that natural frequencies can be determined with adequate accuracy.

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Free Vibration of the Composite Laminated Cylindrical Shells Stiffened with the Axial Stiffeners (길이방향으로 보강된 복합재료 원통쉘의 자유진동)

  • Lee, Young-Shin;Kim, Young-Wann
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.7
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    • pp.2223-2233
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    • 1996
  • The analytical solutions for the free vibration of cross-ply laminated composite cyllindrical shell with axial stiffeners(stringers) are presented usint the energy method. The stiffeners are taken to be smeared over the surface of shell with the smeared stffener theory. The effect of the parameters such as the stacking sequences, the shell thichness, the shell radius-to stringer depth ratio, the stringer depth-to width ratio, the shell length-to radius ratio are studied. By comparison with the previously published experimental results and the analytical results for the stiffened isotropic cylindrical shell and the unstiffened orthotropic composite laminated cylindrical shell, it is shown that natural frequencies can be determined with adequate accuracy.

Study on the Orthogonal Stiffening Characteristics for the Natural Frequencies and Buckling Loads of the Composite Laminated Cylindrical Shells (복합재료원통셸의 고유진동수 및 좌국하중에 대한 직교보강 특성 연구)

  • 이영신;김영완
    • Journal of KSNVE
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    • v.6 no.4
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    • pp.457-467
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    • 1996
  • The analytical solutions for the free vibration and buckling of cross -ply laminated composite cylindrical shell with the orthogonal stiffeners, i. e., axial stiffeners(stringers) and circumferential stiffeners(rings), are presented using the energy method. The stiffeners are assumed to be an integral part of the shell and have been directly included in analysis(it's called discrete stiffener theory). The effect of the parameters such as the stacking sequences, the shell thickness, the shell length-to-radius ratio are studied. By comparison with the previously published analytical results for the stiffened cylindrical shells, it is shown that natural frequencies can be determined with adequate accuracy.

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Optimal Design of Stiffened Laminated Composite Cylindrical Panel with Various Types of Stiffeners (다양한 형태의 보강재로 보강된 원통형패널의 최적설계)

  • Lee Jong-Sun;Won Chong-Jin
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.2
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    • pp.10-15
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    • 2006
  • The optimal design for stiffened laminated composite cylindrical panels under axial compression was studied using linear and nonlinear deformation theories by finite difference energy methods. Various panel structures was made from Carbon/Epoxy USN125 prepreg and considered 3 types stiffeners. Optimal design analyses of panel structure are carried out by the nonlinear search optimizer, ADS. This optimal design results are compared to the FEM result using ANSYS.

Acoustic radiation from resiliently mounted machinery in fluid loaded infinite cylindrical shell with periodic ring supports (보강 원통형 쉘에 탄성 지지된 기계류에 의한 수중 음향 방사)

  • Bae, Soo Ryong;Jung, Woo Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.04a
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    • pp.644-649
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    • 2014
  • Analytical model is derived for the far-field acoustic radiation from machinery installed inside cylindrical shell. The analytical model includes the effect of fluid loading and interactions between periodic ring supports. Transmitted force from machine to a shell can be different by the impedance of shell. In this paper the transmitted force from machinery to a infinite shell through vibration isolator is considered by the impedance of shell. The effect of the shell impedance for acoustic radiation is investigated.

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Transient Analysis of Composite Cylindrical Shells with Ring Stiffeners (링보강 복합재료 원통셸의 과도해석)

  • Kim, Yeong-Wan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.11
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    • pp.1802-1812
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    • 2001
  • The theoretical method is developed to investigate the effects of ring stiffeners on free vibration characteristics and transient response for the ring stiffened composite cylindrical shells subjected to the impulse pressure Loading. In the theoretical procedure, the Love's thin shell theory combined with the discrete stiffener theory to consider the ring stiffening effect is adopted to formulate the theoretical model. The concentric or eccentric ring stiffeners are laminated with composite and have the uniform rectangular cross section. The modal analysis technique is used to develop the analytical solutions of the transient problem. The analysis is based on an expansion of the loads, displacements in the double Fourier series that satisfy the boundary conditions. The effect of stiffener's eccentricity, number, size, and position on transient response of the shells is examined. The results are verified by comparison with FEM results.

An Analysis on the Underwater Sound Radiation from Finite Cylindrical Shell with Stiffeners (유한 보강 원통형 셸 구조에 의한 수중 방사소음 해석)

  • 전재진;정우진
    • Journal of KSNVE
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    • v.6 no.6
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    • pp.717-726
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    • 1996
  • In this report, the underwater sound radiation from finite cylindrical shell with stiffeners which is the basic configuration of submerged vehicle is studied analytically and experimentally. The shell vibrations are obtained by using the shell theory of Sanders-Koitter. The stiffeners and modeled for I-type and the stiffness matrices are obtained by using beam model. In the analytical stuides, the vibrations of cylindrical shell are expressed by using cosine series expansions to consider the arbitrary end boundary conditions. It is agree to the theoretical and experimental results well.

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