• Journal of Welding and Joining
• /
• 제15권1호
• /
• pp.55-65
• /
• 1997

The stress intensity factor has been calculated for the cracked plate subjected to remote normal stress and reinforced with a plate by symmetric spot welding. The solution was based on displacement compatibility condition between the cracked sheet and the reinforcement plate. It is shown that the results from the derived equation for stress intensity factor were agreed with previous solutions. The reinforcement effect gets better as a joining spot is closer to the crack tip and the other joining spots become nearer to the crack surface.

• 한국강구조학회 논문집
• /
• 제19권2호
• /
• pp.191-199
• /
• 2007

본 연구에서는 캔틸레버 공법으로 가설되는 사장교의 최종단계에서 초기평형상태를 구현하기 위한 폐합 방법을 제안하였다. 캔티레버식 가설에 의한 사장교에서 초기평형상태의 구현을 위해서는 거더 폐합단계에서 폐합단면 양측의 연직 처짐, 회전각 및 축방향 변위에 대한 적합조건을 만족시켜야 하는데, 본 연구에서는 실제 시공시 적용 가능한 데릭 크레인의 인양력과 케이블의 장력, 그리고 주탑부에 설치된 유압잭을 이용하여 적절한 폐합이 가능함을 제시하였다. 제안된 방법을 예제 교량의 시공단계 해석에 적용하여 그 타당성을 검증하였으며, 폐합시 축방향 변위에 관한 적합조건의 고려 여부가 주탑의 결과에 큰 영향을 끼치는 것으로 나타났다.

• 한국소음진동공학회논문집
• /
• 제19권10호
• /
• pp.1069-1074
• /
• 2009

A sub-domain method for free vibration analysis of arbitrarily shaped, concave membranes with a deep groove is proposed in the paper. The proposed method divides the concave membrane of interest into two convex regions. The vibration displacement(approximate solution) of each convex region is assumed by linearly superposing plane waves generated at edges of the region. A sub-system matrix for each convex region is extracted by applying a provisional boundary condition to the approximate solution. Finally, a system matrix, which of the determinant gives eigenvalues of the concave membrane, is made by considering the fixed boundary condition(displacement zero condition) at edges and the compatibility condition(the condition of continuity in displacement and slope) at the interface between the two regions. Case studies show that the proposed method is valid and accurate when the eigenvalues by the proposed are compared to those by NDIF method, FEM, or the exact method.

• Journal of Mechanical Science and Technology
• /
• 제15권11호
• /
• pp.1499-1506
• /
• 2001

Various transition elements are used in general for the effective finite element analysis of complicated mechanical structures. In this paper, a solid-to-beam transition finite element, which can b e used for connecting a C1-continuity beam element to a continuum solid element, is proposed. The shape functions of the transition finite element are derived to meet the compatibility condition, and a transition element equation is formulated by the conventional finite element procedure. In order to show the effectiveness and convergence characteristics of the proposed transition element, numerical tests are performed for various examples. As a result of this study, following conclusions are obtained. (1) The proposed transition element, which meets the compatibility of the primary variables, exhibits excellent accuracy. (2) In case of using the proposed transition element, the number of nodes in the finite element model may be considerably reduced and the model construction becomes more convenient. (3) This formulation method can be applied to the usage of higher order elements.

• Structural Engineering and Mechanics
• /
• 제46권1호
• /
• pp.75-90
• /
• 2013

In order to identify damage of highway bridges rapidly, a method for damage identification using dynamic response of bridge induced by moving vehicle and static test data is proposed. To locate damage of the structure, displacement energy damage index defined from the energy of the displacement response time history is adopted as the indicator. The displacement response time histories of bridge structure are obtained from simulation of vehicle-bridge coupled vibration analysis. The vehicle model is considered as a four-degree-of-freedom system, and the vibration equations of the vehicle model are deduced based on the D'Alembert principle. Finite element method is used to discretize bridge and finite element model is set up. According to the condition of displacement and force compatibility between vehicle and bridge, the vibration equations of the vehicle and bridge models are coupled. A Newmark-${\beta}$ algorithm based professional procedure VBAP is developed in MATLAB, and used to analyze the vehicle-bridge system coupled vibration. After damage is located by employing the displacement energy damage index, the damage extent is estimated through the least-square-method based model updating using static test data. At last, taking one simply supported bridge as an illustrative example, some damage scenarios are identified using the proposed damage identification methodology. The results indicate that the proposed method is efficient for damage localization and damage extent estimation.

• Structural Engineering and Mechanics
• /
• 제5권3호
• /
• pp.329-338
• /
• 1997

In this paper a general analytical approach is proposed to analyse the nonlinear response of elastic cable under complex loads. The effect of temperature change on the cable is also considered. From the vertical equilibrium equations of cable, the general analytical formula of vertical displacement is derived. Based on the vertical displacement formula and on the compatibility condition of the cable, the dimensionless equation with respect to cable tension is established. By means of such analytical procedures, the exact solutions of various cable problems can be obtained quickly. The example given in this paper shows that the new procedure is efficient for practical analysis and can be easily implemented by a general computer program without the superposition problem which there has always been in traditional analytical methods.

• 대한토목학회논문집
• /
• 제26권1A호
• /
• pp.55-65
• /
• 2006

이 논문에서는 캔틸레버 공법으로 시공되는 대칭형 강 사장교의 폐합해석법을 제안한다. 폐합시공 전에는 폐합단면 양쪽에서 두개의 독립적인 구조계가 성립되기 때문에 폐합단면에 적절한 단면력을 가해 주어야만 폐합단면에서 수직 처짐과 회전각에 대한 적합조건을 만족시킬 수 있다. 그러나 실제 시공에서는 폐합단면에 단면력을 재하하는 것이 거의 불가능하기 때문에 시공 중에 실제로 교량에 재하할 수 있는 외력에 의하여 적합조건을 만족시켜야 한다. 이 논문에서는 몇 개 케이블의 무응력 길이와 데릭 크레인의 인양력을 조정하여 적합조건을 만족시킬 수 있는 해석 방법을 제안한다. 적합조건식은 케이블의 무응력 길이와 크레인 인양력에 대하여 비선형이므로 Newton-Raphson 방법에 의하여 반복적으로 푼다. 케이블 부재는 탄성현수선 요소를 사용하여 모델링하였고, 주탑과 거더는 일반적인 3차원 뼈대요소를 사용하여 이산화하였다. 교량의 케이블 무응력 길이와 인양력에 대한 변위 민감도는 평형방정식을 직접 미분하여 계산하였다. 주어진 신뢰도 구간에서 시공 오차를 예측하기 위한 몬테-카를로 모사법을 제안하였다. 제안된 방법을 제 2 진도대교의 폐합시공에 적용하여 그 타당성과 효율성을 검증하였다.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2001년도 춘계학술대회 논문집
• /
• pp.136-143
• /
• 2001

In this study, a numerical analysis for soil-pile interaction systems in multi-layered half planes under a forced vibration is presented. The soil-pile interaction system is divided into two parts, so called near field and far field. The near field soil using finite elements and piles using beam elements are modeled. The far field soil media is implemented using boundary elements those can automatically satisfy the condition of wave radiation. These two fields are numerically coupled by imposing displacement compatibility condition at the interface between the near field and the far field. For the verification, the forced vibration test was simulated and the response under horizontal and vertical harmonic loads at the pile cap in the layered half plane was determined. The results are compared to the theoretical and experimental results of the literatures to verify the proposed soil-pile interaction analysis formulation.

• 콘크리트학회논문집
• /
• 제26권6호
• /
• pp.687-694
• /
• 2014

이 연구에서는 철근콘크리트 전단벽의 경계요소의 연성설계를 위한 변위연성비모델을 제시하였다. 부재의 길이에 따른 곡률과 자유단에서의 변위를 산정하기 위한 전단벽의 단면의 변형률 및 내부힘들의 분포는 베르누이(Bernoulli)의 정리, 변형률 적합조건 및 힘의 평형조건을 이용하여 이상화하였다. 경계요소내의 횡보강근에 의한 구속효과는 Razvi and Saatcioglu에 의해 제시된 콘크리트의 응력-변형률 관계를 이용하여 고려하였다. 항복시 및 최대내력 이후 최대모멘트 80%에서의 곡률은 등가소성 힌지길이 개념을 도입하여 변위값으로 환산하였다. 일반화된 변위연성비의 모델은 다양한 범위에서 수행된 변수연구로부터 얻어진 데이터들의 회귀분석을 통하여 단순식으로 정립되었다. 제시된 단순모델은 실험결과 대비 평균, 표준편차 및 변동계수가 각각 1.05, 0.19 및 0.18로 대부분의 실험결과의 경향을 잘 예측하였다. 따라서 제시된 모델은 경계요소에서 소요연성비에 따른 횡보강근의 상세를 결정하는데 쉽게 이용될 수 있을 것으로 기대된다.

• Nuclear Engineering and Technology
• /
• 제41권3호
• /
• pp.335-346
• /
• 2009

This paper deals with a hydroelastic vibration analysis of two rectangular plates partially coupled with a liquid, which is bounded by two plates and two rigid side walls. The wet displacement of each plate is assumed to be a combination of the modal functions of a dry uniform beam with a clamped boundary condition. As the liquid is assumed to be an ideal liquid, the displacement potential satisfying the Laplace equation is determined so that the liquid boundary conditions can meet the requirements at the rigid surfaces and the free liquid surface. The wet dynamic modal functions of each plate are expanded by using the finite Fourier transform to obtain an appropriate form of the compatibility requirement along the contacting surfaces between the plates and the liquid. The liquid-coupled natural frequencies of the plates are derived by using the Rayleigh-Ritz method. Finite element analyses using commercial software are carried out to verify the proposed theory. It is observed that the theoretical method agrees excellently with the three-dimensional finite element analyses results. The effects of the liquid depth and the liquid thickness on the normalized natural frequencies are investigated to identify the dynamic characteristics of the liquid coupled system.