• 한국전산구조공학회논문집
• /
• 제13권1호
• /
• pp.87-95
• /
• 2000

양단이 단순지지 상태이고, 정현상으로 taper진 부재의 두 고유치(탄성임계하중과 횡방향 고유진동수)를 유한요소법으로 산정하였다. 그 결과로 얻어진 고유치의 계수들을 실무에 종사하는 구조 기술자들이 쉽게 이용할 수 있도록 각각의 경우에 대하여 간단한 대수 방정식으로 표시하였다. 유한요소법으로 구한 고유치 계수값과 대수 방정식에 의한 추정 계수값들의 상관계수는 어느 경우에나 거의 단위치(1)에 가까운 값으로 대수 방정식의 정당성을 뒷받침 하였다. 횡방향 진동수에 미치는 압축하중의 영향도 검토하였다. 이를 위하여 부재에 작용하는 축방향력을 차례로 증가시키면서 여기에 대응하는 진동수를 산정하였다. 그 결과 압축하중비 (P/P/sub cr/)와 진동수 비의 제곱 ((ω/ω/sub 0/)²)의 합은 어느 경우에나 거의 단위치(1)로 나타났다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2000년도 봄 학술발표회논문집
• /
• pp.263-270
• /
• 2000

It is generally known that the stress and displacement of a member or a system under dynamic load with frequency ω are magnified by the factor 1/[1-(ω/ω/sub 0/)sup/ 2/]. When the member assumes non-prismatic shape, the natural frequency, ω/sub 0/ is hard or impossible to determine if the conventional method are adopted. In these cases, the numerical methods are provide powerful tools for the solution of frequency problems. In this paper, finite element method is applied to determine the natural frequencies of the non-symmetrically tapered members. The shape of the member is assumed to change sinusoidally along its axis. The results obtained by finite element method are expressed by some simple algebraic equations. The estimated frequencies calculated by the proposed equations coincide well with those by the finite element method.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2000년도 가을 학술발표회논문집
• /
• pp.59-66
• /
• 2000

It is generally known that the lateral frequency( ω) of the vibration of a prismatic beam-column decreases according to the rele (equation omitted) (ω/sub 0/=natural frequency). In the cases of tapered members, the determination of P/ sub/ cr/(elastic critical load) and ω/ sub 0/ are not easy. Furthermore, the relationship between the compressive load and frequency can not be determined by the conventional analytical method. The axial force-frequency relationship of sinusolidally non-symmetrically tapered members with different shapes were investigated using the finite element method. To obtain the two eigenvalues, the axial thrust was increased step by step and the corresponding frequency was calculated. The result indicated that the axial thrust of the elastic critical load ratio and the square of the frequency ratio can be approximately represented in any case by a straight line. Finally, the linear relationship is also applicable to the sinusolidally non-symmetrically tapered member.