판 및 보강평판의 좌굴해석

Abstract

본 논문은 사변 단순지지하에서 일축 및 이축 압축하중을 받는 판과 보강 평판의 좌굴 해석을 위하여 준 행석적인 방법(Semi-analytical Method을 이용하였고 이를 컴퓨터를 이용한 수치해석법을 사용하여 해를 얻었다. 여기 사용된 준 해석적인 방법을 Ritz법을 기초로 하였고, Mindlin평판 이론을 적용함으로써 전단변형의 효과를 고려에 넣었다.

특히 종래의 해석적인 방법과 본 논문의 차이점은 종래의 방법이 Kirchhoff판 이론을 근거로 평판 처짐변위 w에 대한 경계조건을 만족하는 함수를 하나 가정하였나 여기서는 평판이론에 근거하여 변위와 중립면 에서의 회전을 나타내는 3개의 변위함수를 독립적으로 가정하여 정식화 하였다.

본 논문에 의한 결과치들은 고전적인 방법과 유한요소법에 의한 결과치들과 잘 일치하며 전산시간면에서는 오히려 유한요소법보다 유리한 방법임을 확인하였다. 일반적으로 비교적 두께가 두꺼운 평판의 경우는 mindlin평판으로 가정한 해석결과가 고전적인 박판해의 결과치보다는 낮은 좌굴하중을 나타냄을 알았다.

A semi-anslytical method is formulated for the buckling analysis of plates or stiffened plates subjected to uniaxial or biaxial compression with all the edges simply supported and computer program has developed based on this method.

The present method is based on Ritz method and the effects of shear deformation to buckling loads is considered by appling Mindlin's plate theory.

In the present method, the rotational displacement ?? and ?? are involved as the

variables which are independent of the lateral deflection ??. This is the different point from the other analytical method based on Kirchhoff's plate theory in which lateral deflection only is taken into account.

The present results show good agreement with those obtained by the classical analysis or by finite element method. Comparison of the precent numerical results has been made with those by the finite element for stiffened plate under uniaxial and biaxial compressive load and simply supported boundary condition.

It general, it is found that the precent numerical method gives lower buckling load than those obtained by the classical plate theory. For the stiffened plates, equi-distant stiffeners pararell to the loading direction are more effective when comparing with those perpendicular to the loading direction. When the height of stiffeners is over a certain value, stiffeners perpendicular to the loading direction act as a panel braker only rather than the means of increasing buckling loads.

A semi-anslytical method is formulated for the buckling analysis of plates or stiffened plates subjected to uniaxial or biaxial compression with all the edges simply supported and computer program has developed based on this method.

The present method is based on Ritz method and the effects of shear deformation to buckling loads is considered by appling Mindlin's plate theory.

In the present method, the rotational displacement ?? and ?? are involved as the

variables which are independent of the lateral deflection ??. This is the different point from the other analytical method based on Kirchhoff's plate theory in which lateral deflection only is taken into account.

The present results show good agreement with those obtained by the classical analysis or by finite element method. Comparison of the precent numerical results has been made with those by the finite element for stiffened plate under uniaxial and biaxial compressive load and simply supported boundary condition.

It general, it is found that the precent numerical method gives lower buckling load than those obtained by the classical plate theory. For the stiffened plates, equi-distant stiffeners pararell to the loading direction are more effective when comparing with those perpendicular to the loading direction. When the height of stiffeners is over a certain value, stiffeners perpendicular to the loading direction act as a panel braker only rather than the means of increasing buckling loads.