• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1203-1214
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• 1989

본 연구에서는 화이버각도, 경계조건 및 하중형태의 변화에 따라 적층 복합재료원통 셸 구조물의 수치예를 제시하고, NASTRAN수치결과 및 기존 문헌들과 비교하여 구하여진 결과의 타당성을 입증하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.630-648
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• 1992

The minimum weight design for simply-supported isotropic or symmetrically laminated stiffened cylindrical shells subjected to various loads (axial compression or combined loads) is studied by a nonlinear mathematical search algorithm. The minimum weight design in accomplished with the CONMIN optimizer by Vanderplaats. Several types of buckling modes with maximum allowable stresses and strains are included as constraints in the minimum weight design process, such as general buckling, panel buckling with either stingers or rings smeared out, local skin buckling, local crippling of stiffener segments, and general, panel and local skin buckling including stiffener rolling. The approach allows the consideration of various shapes of stiffening members. Rectangular, I, or T type stringers and rectangular rings are used for stiffened cylindrical shells. Several design examples are analyzed and compared with those in the previous literatures. The unstiffened glass/epoxy, graphite/epoxy(T300/5208), and graphite/epoxy aluminum honeycomb cylindrical shells and stiffened graphite/epoxy cyindrical shells under axial compression are analyzed through the present approach.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.2
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• pp.205-212
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• 1989

The minimum weight design for the simply supported orthogonally stiffened cylindrical shell subjected to axial compression is studied by a mathematical programming. A smeared-out method is used for the computation of buckling load in the optimization process and optimization is accomplished by a gradient projection method. Maximum eight design variables and twenty-one inequality constraints considering the buckling, stress and geometric restraints are used. The three stringer types are considered as the optimization models : (1) rectangular stringer (2) I-stringer (3) T-stringer. Two design examples are compared with those in the other studies and the results demonstrate the validity of the present study. From the calculation the design with T-stringer can be more efficient than the one with rectangular or I-stringer.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.807-819
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• 1989

Buckling and vibration of laminated non-circular cylindrical shells with constant thickness and simply supported boundary condition is considered. Governing equations are derived based on the Donnell and Flugge shell theory and Galerkin method is applied for the numerical analysis. Comparisons are made between present results and others. Variations of frequency parameter and buckling load parameter on the change of stacking angle, eccentricity parameter and shell theories are investigated. Conclusion of this study is as follows: (1) General solutions of buckling and vibration of laminated non-circular cylindrical shell are obtained. (2) Frequency parameter is decreased as the initial axial load is increased. (3) In general, frequency and buckling load parameter of laminated non-circular cylindrical shells are decreased as increasing of eccentricity parameter and stacking angle.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.4
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• pp.487-496
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• 1985

회전하는 축대칭 얇은 셸구조물의 진동 특성을 유한요소법에 의하여 해석하였다. 2개의 절점을 가진 Conical Frustrm 형태의 축대칭 요소를 사용하였으며 원주방향의 변위는 Fourier Series로 분해하여서 방정식의 수를 상당히 줄일 수 있었다. Sanders-Koiter의 셸이론을 사용하였으며 진 동 모우드는 회전의 영향을 설명하기 위하여 대칭 및 비대칭 모우드를 모두 고려하였다. Coriolis 행렬을 포함하는 운동방정식에서 고유 진동수를 계산하기 위해서 질량, 강성 및 Coriolis 행렬로 이루어지는 Hermitian 행렬의 Sturm Sequence Property를 이용하였으며, 좁은 밴드를 갖는 대형 행렬에 알맞는 Determinant Search 방법을 확장하여 고유진동수 및 벡터를 구하였다. 원통형 셸에 대하여 정지한 경우 계산한 고유진동수를 실험치 및 이론치와 비교한 결과 잘 일치됨을 알 수 있었다. 여러 가지 회전 속도에 대해서 얻어진 고유진동스를 이론치와 비교한 결과 잘 일치 됨을 알 수 있어\ulcorner며 회전의 영향으로 traveling wave진동의 현상이 나타남을 알 수 있었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.334-339
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• 1998

The free vibration analysis of the simply supported steel and composite cylindrical shells are investigated. The natural frequencies and mode shapes of the shell are experimentally obtained by impact testing using an impact hammer and an accelerometer. The effects of the material and geometry on the vibrational characteristics of the shell are examined. The experimental results are compared with the analytical and a finite element results. They showed good agreement with each other.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.359-364
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• 1998

The effects of boundary conditions on natural frequencies for the ring stiffened composite cylindrical shells are investigated by theoretical method. The Love's thin shell theory and the discrete stiffener theory with beam functions in the Ritz procedure are used to derive the frequency equation. Five different boundary conditions such as clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study. Also, the experimental investigation is presented to validate the theoretical results.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.211-214
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• 1999

The stress distribution around the cutout of composite cylindrical shells with a circular or elliptical reinforced cutout subjected to axial compression or tension is studied by asymptotic method. Analytical solutions used a Donnell type orthotropic shell theory are presented by the defined stress concentration factor and are compared to experimental results. The experiment used the universal testing machine (UTM), strain gage and fixtures designed/manufactured for axial tension test of a cylindrical shell is carried and the composite material used in the experiment is plain weave glass fiber reinforced plastic (GFRP).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.112-116
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• 1998

The objective of this study is to investigate effects of prebuckling on the buckling of laminated composite cylindrical shells. Axial compression is considered for laminated composite cylindrical shells with length to radius ratios. The shell walls are made of a laminate with several symmetric ply orientations. This study was made using finite difference energy method, utilizing the nonlinear bifurcation branch with nonlinear prebuckling displacements. The results are compared to the buckling loads determined when membrane prebuckling displacements are considered.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.205-210
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• 1997

The analysis of the free vibrations of a circular cylindrical shell with a logitudinal, interior rectangular plate is performed. The natural frequencies and the mode shapes of the combined shells are experimentally obtained by impact testing using an impact hammer and an accelerometer. The effects of the position of the plate on the frequencies and mode shapes of the combined system are examined. The experimental results are compared with a finite element analysis and show good agreement.