• Structural Engineering and Mechanics
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• 제64권2호
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• pp.225-232
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• 2017

Leaning-type arch bridge is a new spatial structural system composed of two vertical arches and two leaning arches. So far there has been no contrast analysis of leaning type arch bridge with different systems. This paper focus on a parametric study of leaning type arch bridge with different systems to find the influential rules on structural forces and stability and to provide some reference for practical designs. The parametric analysis is conducted with different rise-to-span ratios and bending rigidities of arch ribs by comparing internal forces. The internal forces decline obviously with the increase of the rise-to-span ratio. The bending moments at the centers of the main arches and the leaning arches are sensitive to the bending rigidities of arch ribs. Parametric studies are also carried out with different structural systems and leaning angles of the leaning arch by comparing the static stability. The lateral stiffness of leaning-type arch bridge is less than the in-plan stiffness. Compared with the leaning-type arch bridge without thrust, the leaning-type arch bridge with thrust has a lower stability safety coefficient. The stability safety coefficient rises gradually with the increase of inclining angle of the leaning arch. This study shows that the rise-to-span ratio, bending rigidities of arch ribs, structural system and leaning angles of the leaning arch are all critical design parameters. Therefore, these parameters in unreasonable range should be avoided.

• 동력기계공학회지
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• 제16권6호
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• pp.38-44
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• 2012

In this paper, the bending characteristics of the corrugated plates is analyzed. The trapezoidally, triangularlly and sinusoidally corrugated plates are considered. The corrugated plate is treated as an orthotropic plate that has different flexural properties in two perpendicular directions. The equivalent bending and twisting rigidities for the equivalent orthotropic plates are derived. The equivalent flexural rigidities are estimated under the following postulations: (1) The angle of continuously corrugated plate is not changed after the deformation. (2) When the pure bending moment is applied in corrugated direction of the plate, the its plane is in pure bending. Several numerical examples are analyzed with the proposed method and compared with published results.

• Structural Engineering and Mechanics
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• 제21권6호
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• pp.677-698
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• 2005

In engineering practice, tubular connections are usually assumed pinned or rigid. Recent research showed that tubular joints may exhibit non-rigid behavior under axial or bending loads. This paper is concerned with establishing a new classification for tubular joints and investigating the effect of joint rigidity on the global behavior of CHS (Circular Hollow Section) lattice girders. Parametric formulae for predicting tubular joint rigidities are proposed, which are based on the finite element analyses through systematic variation of the main geometric parameters. Comparison with test results proves the reliability of these formulae. By considering the deformation patterns of respective parts of Vierendeel lattice girders, the boundary between rigid and semirigid tubular connections is built in terms of joint bending rigidity. In order to include characteristics of joint rigidity in the global structural analysis, a type of semirigid element which can effectively reflect the interaction of two braces in K joints is introduced and validated. The numerical example of a Warren lattice girder with different joint models shows the great effect of tubular joint rigidities on the internal forces, deformation and secondary stresses.

• Steel and Composite Structures
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• 제9권4호
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• pp.303-323
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• 2009

Charts for the bending moments in the closed rib orthotropic deck plate are derived, based on the method originally introduced by Pelikan and Esslinger. New charts are done for EN 1991-2 traffic load distribution schemes. The governing Huber plate equation is solved utilizing Fourier series for various bridge deck plate boundary conditions. Bending moments are given as a function of deck plate rigidities and span length between cross beams. Old diagrams according to DIN 1072, the new ones according to EN 1991-2 and FE analyses results are compared. For typical bridge orthotropic deck plates, it can be concluded that the new EN 1991-2 traffic loads produce larger mid-span bending moments when two lane schemes are used, then those of DIN 1072. For support moments, DIN 1072 gives larger values for any number of lanes, especially under span lengths of 5m. The relevant differences are up to 25%.

• 한국강구조학회 논문집
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• 제19권5호
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• pp.463-472
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• 2007

본 연구에서는 균일한 휨모멘트가 작용하는 파형강판 복부판 I-거더의 횡-비틂 좌굴강도에 관하여 이론적 접근 및 유한요소해석을 이용하여 연구를 수행하였다. 횡-비틂 좌굴 강도는 박판 구조를 갖는 I-단면의 휨부재를 설계 하는데 중요한 인자이다. 하지만 파형강판 복부판 I-거더의 뒴비틀림 상수와 같은 비틀림 거동에 대한 이해가 현재까지는 부족한 실정이며, 이에 대한 연구가 필요하다. 본 연구에서는 휨 및 순수 비틀림 상수를 기존 연구자들의 결과를 이용하여 요약하였으며, 그 후 파형강판 복부판 I-거더 단면의 전단 중심의 위치와 뒴비틀림 상수를 유도하였다. 이러한 단면 상수들을 이용하여 파형강판 복부판 I-거더의 횡-비틂 좌굴 강도를 결정하였으며, 유한요소해석을 수행하여 제안된 파형강판 복부판 I-거더의 횡-비틂 좌굴 강도를 검증하였다. 마지막으로 파형강판의 기하학적 제원이 횡-비틂 좌굴강도에 미치는 영향에 관하여 연구를 수행하였다.

• Steel and Composite Structures
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• 제46권5호
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• pp.709-718
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• 2023

The absence of an important portion of the web plate in steel beams with multiple circular perforations, cellular beams, causes the web plate to undergo distortions prior to and during lateral torsional buckling (LTB). The conventional LTB equations in the codes and literature underestimate the buckling moments of cellular beams due to web distortions. The present study is an attempt to develop analytical methods for estimating the elastic buckling moments of cellular beams. The proposed methods rely on the reductions in the torsional and warping rigidities of the beams due to web distortions and the reductions in the weak-axis bending and torsional rigidities due to the presence of web openings. To test the accuracy of the analytical estimates from proposed solutions, a total of 114 finite element analyses were conducted for six different standard IPEO sections and varying unbraced lengths within the elastic limits. These analyses clearly indicated that the LTB solutions in the AISC 360-16 and AS4100:2020 codes overestimate the buckling loads of cellular beams within elastic limits, particularly at shorter span lengths. The LDB solutions in the literature and the Eurocode 3 LTB solution, on the other hand, provided conservative buckling moment estimates along the entire range of elastic buckling.

• International Journal of Aerospace System Engineering
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• 제6권2호
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• pp.1-10
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• 2019

In this paper, the probabilistic free vibration analysis of a geometrically coupled cantilever wing with uncertain material properties is carried out using stochastic finite element (SFEM) based on first order perturbation technique. Here, both stiffness and damping of the system are considered as random parameters. The bending and torsional rigidities are assumed as spatially varying second order Gaussian random fields and represented by Karhunen Loeve (K-L) expansion. Here, the expected value, standard deviation, and probability distribution of random natural frequencies and damping ratios are computed. The results obtained from the present approach are also compared with Monte Carlo simulations (MCS). The results show that the uncertain bending rigidity has more influence on the damping ratio and frequency of modes 1 and 3 while uncertain torsional rigidity has more influence on the damping ratio and frequency of modes 2 and 3.

• 한국의류학회지
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• 제24권7호
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• pp.1015-1024
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• 2000

The purpose of this study is 1) to analyse the bending property of the fused fabric and each component of the fused fabrics. 2) to examine the effect of fusing temperature on the bending property of the fused interlining and fused fabrics. 3) to examine the changes of B/W, 2HB/W and TAV of the fused fabrics according to the types of face fabric, interlining, fusing temperature. Five types of wool fabric, four types of shingosen fabric and four types of interlining were used for this study. The fusing condition in this study were the three types of fusing temperature of 10$0^{\circ}C$, 12$0^{\circ}C$, 14$0^{\circ}C$, the pressure of 4 kgㆍf/$cm^2$, and pressing time of 12 seconds. The results obtained from this study were as follows. 1) The bending rigidities and hysteresis of fabrics after fusing were increased. The bending behavior of fused fabrics were governed by the bending behavior of face fabric and interlinings and $\alpha$$_{B}$ values. 2) The KES standardized basic values of B/W and 2HB/W were increased after fusing. The B/Ws of fused fabrics were mainly determined by the $\alpha$$_{B}$ values of interlinings. The 2HB/Ws of fused fabrics seemed to be controlled by the fusing temperature. 3) The changes of TAVs of wool fused fabrics differed from those of shingosen fused fabrics. As the $\alpha$$_{B}$ values of fabric were larger and fusing temperature were increased, the TAVs of wool fused fabrics were smaller though those of shingosen fused fabrics were larger. 4) The TAVs of fused fabrics were highly correlated with the B/Ws of fused fabrics. In the case of wool fused fabrics, the TAVs of fused fabrics were negativly correlated with the 2HB/Ws of wool fabrics and used interlinings.nings.

• 전산구조공학
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• 제10권1호
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• pp.135-148
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• 1997

본 논문은 면내휨을 받는 2변 탄성지지 2변 단순지지 보강장방형판에 대한 유한요소법을 이용하고, 비보강장방형판에 대해 고전적 해석법에 의해 좌굴해석한 것이다. 4변 단순지지, 2변 단순지지 및 2변 고정 장방형 판에 대해 기존해와 고전적 해석해 및 유한요소해을 비교하여 고전적 해석방법 및 유한요소법의 신뢰도를 입증하였다. 장방형 보강재의 뒤틀림 강성은 무시될 수 있으므로 탄성지지변의 보강재는 뒤틀림의 영향을 파악하기 위해 I형을 사용하였다. 탄성지지변을 갖는 장방형 판의 좌굴강도가 비틀림 강성 및 뒤틀림 강성에 따라 유한요소법 및 고전적 해석법에 의해 계산되고 비교되었다. 판의 지지변 사이에 보강재가 있는 경우 4변 단순지지, 2변 단순지지 및 2변 고정 보강장방형판에 대해 유한요소법에 의한 좌굴강도는 장방형판요소와 비틀림 및 뒤틀림을 고려한 보요소의 강성매트릭스를 조합하여 고유치 문제를 풀므로써 계산될 수 있다. 유한요소법에 의해 지지변 사이의 장방형 보강재 위치와 지지변 상의 I형 보강재의 비틀림(J) 및 뒤틀림 상수 (I/sub W/)에 따른 보강장방형판의 좌굴강도를 구하여 비교하고 효율적인 보강재의 위치를 결정하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.3-10
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• 2002

Recently, arches are used structurally because of their high in-plane stiffness and strength, which result from their ability to transmit most of the applied loading by axial forces actions, so that the bending actions are reduced. On the other hand, the resistances of arches to (out-of-plane,) flexural-torsional behavior depend on the rigidities EI/sub y/, for lateral bending, GJ for Uniform torsion, and EI/sub w/ for warping torsion which are related to axial stress for flexural-torsional behavior. The resistance of an arch to out-of-plane behavior may be reduced by its in-plane curvature, and so it may require significant lateral bracing. Thus. it is supposed that In-plane preloading which cause an axial stress, have an effect on out-of-plane free vibration behavior of arches. Because axial stresses caused increase or decrease out-of-plane stiffness. But study about this substance is insufficient. In this thesis, We will study an effect of preloading on lateral free vibration of arches, using finite element method based on Kang and Yoo's curved beam theory (about curved beam element have 7 degree of freedom including warping) with FORTRAN programming.