• 한국강구조학회 논문집
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• 제13권1호
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• pp.101-113
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• 2001

본 연구의 주된 목적은 전단 층을 갖는 two-parameter 탄성지반 위에 놓인 복합적층판의 처짐에 관한 규명이다. 본 논문은 탄성지반에 놓인 비등방성 구조의 변형거동과 2중 조화함수를 이용한 3차 전단변형이론의 확장에 초점을 두고 있다. 유도된 식들을 검증하기 위해 Timoshenko의 탄성지반 위에 놓인 단순지지 된 등방성판과 LUSAS 프로그램에 의한 이방성판의 처짐과 비교하였으며 본 연구의 결과들은 등방성판과 이방성판의 결과와 매우 정확히 일치함을 알 수 있었다. 처짐에 관한 수치해석결과들은 폭-두께 비, 형상 비 재료 비등방성과 전단지반계수 등에 따른 효과를 보여준다.

• 한국시뮬레이션학회논문지
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• 제8권2호
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• pp.111-122
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• 1999

The paper presents a stability analysis of uniform Timoshenko beams resting on two-parameter elastic foundations. The two-parameter elastic foundations were considered as a shearing layer and Winkler springs in soil models. Governing equations of motion were derived using the Hamilton's principle and finite element analysis was performed and the eigenvalues were obtained for the stability analysis. The numerical results for the buckling stability of beams under axial forces are demonstrated and compared with the exact or available confirmed solutions. Finally, several examples were given for Euler-Bernoulli and Timoshenko beams with various boundary conditions.

• 한국강구조학회 논문집
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• 제13권5호
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• pp.443-455
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• 2001

전단 층을 갖는 2개 매개변수 탄성지반 위에 놓인 복합재료 적층판에서 휨 진동 및 좌굴해석을 위해 에너지 방법을 사용해 탄성해를 구하였다. 복합재료 적층판의 점탄성 해석은 유사-탄성방법을 사용해 탄성해를 구하였다. 전단에 의한 효과는 3창 전단변형이론을 적용하여 고려하였다. 유도된 식들을 검증하기 위해 LUSAS 프로그램에 의한 탄성지반위에 놓인 이방성 판의 처짐과 비교하였다. 점탄성 휨 진동 및 좌굴해석에 관한 수치해석결과들은 적층순서, 적층 수 재료 비등방성과 전단지반계수 등에 따른 효과를 보여 준다.

• 소음진동
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• 제10권6호
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• pp.1075-1082
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• 2000

본 논문은 이중 탄성기초 위에 놓인 테이퍼진 티모센코 보의 진동과 동적 안정성에 대한 연구로써, 이중 탄성기초는 지반모델에서 흔히 이용되는 분포 Winkler 스프링들과 전단기초층으로 구성된다. 보의 전단변형과 회전관성이 고려되고, 지배방정식은 Halmilton원리를 이용한 에너지 표현식에 의해 유도된다. 고유진동수와 좌굴하중을 구하기 위해 관계되는 고유치 문제를 풀며, 출력을 받는 보의 진동에 대한 수치해석결과들이 제시되는 다른 방법을 사용한 유용한 해의 결과들과 비교된다. 출력을 받고 탄성기초 위에 놓인 테이퍼진 티모센코 보의 고유진동수, 모드 형상, 그리고 임계하중 값들이 다양한 테이퍼 두께의 비, 전단기초 파라미터, Winkler 기초파라미터, 경계조건의 변화에 대해 조사된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.596-601
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• 2000

The paper presents free vibration and stability analyses of a non-uniform Timoshenko beam resting on a two-parameter elastic soil. The soil parameters can vary along the spat and is assumed to be two-parameter model including the effects of both transverse shear deformation and elastic foundation Governing equations related to the vibration and the stability of the beam are derived from Hamilton's principle, and the resulting eigen-value problems can be solved to give natural frequencies and critical force by finite element method. Numerical results for both vibration and stability of beams under an axial force are presented and compared with other available solutions. Finally, vibration frequencies, mode shapes and critical forces are investigated for various thickness ratios, shear foundation parameter, Winkler foundation parameter and boundary conditions of tapered Timoshenko beams.

• 한국소음진동공학회논문집
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• 제11권8호
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• pp.357-363
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• 2001

This paper presents the application of the technique Q( differential transformation to the vibration analysis of beams resting on variable two-parameter elastic foundations. The closed form series solutions for beams are obtained for various boundary conditions. Numerical calculations are carried out and compared with previously published results. The results obtained by the present method agree very well with those reported in the previous works. The present analysis shows the usefulness and validity of differential transformation in solving nonlinear problem of the free vibration.

• Smart Structures and Systems
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• 제15권6호
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• pp.1569-1582
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• 2015

Two hyperbolic displacement models are used for the bending response of simply-supported orthotropic laminated composite plates resting on two-parameter elastic foundations under mechanical loading. The models contain hyperbolic expressions to account for the parabolic distributions of transverse shear stresses and to satisfy the zero shear-stress conditions at the top and bottom surfaces of the plates. The present theory takes into account not only the transverse shear strains, but also their parabolic variation across the plate thickness and requires no shear correction coefficients in computing the shear stresses. The governing equations are derived and their closed-form solutions are obtained. The accuracy of the models presented is demonstrated by comparing the results obtained with solutions of other theories models given in the literature. It is found that the theories proposed can predict the bending analysis of cross-ply laminated composite plates resting on elastic foundations rather accurately. The effects of Winkler and Pasternak foundation parameters, transverse shear deformations, plate aspect ratio, and side-to-thickness ratio on deflections and stresses are investigated.

• Structural Engineering and Mechanics
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• 제4권2호
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• pp.149-162
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• 1996

A postbuckling analysis is presented for a simply supported, moderately thick rectangular plate subjected to combined axial compression and uniform temperature loading and resting on a two-parameter elastic foundation. The two cases of thermal postbuckling of initially compressed plates and of compressive postbuckling of initially heated plates are considered. The initial geometrical imperfection of the plate is taken into account. The formulations are based on the Reissner-Mindlin plate theory considering the first order shear deformation effect, and including the plate-foundation interaction and thermal effect. The analysis uses a deflection-type perturbation technique to determine the buckling loads and postbuckling equilibrium paths. Numerical examples cover the performances of perfect and imperfect, moderately thick plates resting on Winkler or Pasternak-type elastic foundations. Typical results are presented in dimensionless graphical form.

• Structural Engineering and Mechanics
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• 제57권6호
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• pp.969-988
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• 2016

Vibration analysis of the beams on elastic foundation has gained the great interest of many researchers. In the literature, there are many studies that focus on the free vibration analysis of the beams on one or two parameter elastic foundations. On the other hand, there are no sufficient studies especially focus on the comparison of dynamic response including the bending moment and shear force of the beams resting on Winkler and two parameter foundations. In this study, dynamic response of the axially loaded Timoshenko beams resting on modified Vlasov type elastic soil was investigated by using the separation of variables method. Governing equations were obtained by assuming that the material had linear elastic behaviour and mass of the beam was distributed along its length. Numerical analysis were provided and presented in figures to find out the differences between the modified Vlasov model and conventional Winkler type foundation. Furthermore, the effect of shear deformation of elastic soil on the dynamic response of the beam was investigated.

• 한국전산구조공학회논문집
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• 제15권2호
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• pp.367-377
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• 2002

이 논문은 탄성지반 위에 놓인 낮은 아치의 자유진동에 관한 연구이다. Pasternak가 제안한 두 개의 매개변수로 표현되는 지반모형을 채택하여 대상아치의 자유진동을 지배하는 미분방정식을 유도하였다. 양단회전 및 양단고정의 단부 조건을 갖는 두 종류의 아치선형을 유도된 지배방정식에 적용하여 Galerkin method로 해석함으로써 최저차 대칭 및 역대칭 고유진동수 방정식을 산출하였다 아치높이, Winkler지반계수 및 전단지반계수가 고유진동수에 미치는 영향을 분석하였으며, 아치선형이 고유진동수에 미치는 영향을 분석하였다.