A Study on The Strength Estimation of Stiffened Cylindrical Members

Abstract

보강원통쉘은 잠수함의 선각, 각종 해양구조물의 주요 부재등으로 활용도가 대단히 크나 구조적 거동이 아주 복잡해서 그 강도추정이 해석적인 방법이나 유한요소법등의 수치 해법에 의해 합리적으로 이루어지지 못하고, 선형탄성 좌굴하중에 실험자료들로 부터 유도된 감소계수를 곱해서 최종강도를 추정하는, 반경험적 방법에 전적으로 의존하고 있다. 이와 같은 반경험식의 정확도는 제한된 ?피窩米掃? 부터 얻어지는 감소계수의 정확도에 따라 결정된다고 볼 수 있다.

본 논문에서 이와 같이 원통부재의 강도해석에 세계적으로 널리 사용되는 API 설계규정과 BS5500 등의 반경험식들을 조사하고 유한요소해석법을 활용하여 반경험식을 개선하는 방안을 제시한다.

In spite of their frequent uses as submarine pressure hulls and major structural members of various offshore structures, the complicated structural behaviours of cylindrical shells make their design not to depend on analytical or numerical method but on semi-empirical method. The basic concept of the latter is that the ultimate strength of the member can be thought as linear elastic buckling loads multiplied by reduction factors derived from the test data. So the most important thing in making the semi-empirical formulae is to derive the reduction factors efficiently from the limited number of test data which can not cover the whole range of the cylinder gemetries.

In this paper worldwidely used semi-empirical formulae, API code and BS5500, are investigated and finally measures are proposed to improve them.

In spite of their frequent uses as submarine pressure hulls and major structural members of various offshore structures, the complicated structural behaviours of cylindrical shells make their design not to depend on analytical or numerical method but on semi-empirical method. The basic concept of the latter is that the ultimate strength of the member can be thought as linear elastic buckling loads multiplied by reduction factors derived from the test data. So the most important thing in making the semi-empirical formulae is to derive the reduction factors efficiently from the limited number of test data which can not cover the whole range of the cylinder gemetries.

In this paper worldwidely used semi-empirical formulae, API code and BS5500, are investigated and finally measures are proposed to improve them.