• 한국농공학회지
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• 제28권2호
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• pp.87-92
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• 1986

The differential equation, which can determine the dynamic critical loads for low parabcoic arches, is derived in this study. The dynamic critical loads of the parabolic arches subjected to a concentrated step load are nummerically analyzed for the changes of load positions. In cases of arches with different end conditions (both hinged, fixed hinged, both fixed), the effect of end conditions and that of the rises are investigated in detail. The summary of the results are the following: 1)The snapthrough does not occur when the rise of arch is very low, and the bifurcation appears clearly as the rise of arch increases. 2)The regions in which the dynamic critical loads are not defined for the both ends fixed are broader than that for the both ends hinged. 3)For all case, the load positions of minimum dynamic critical loads exsit at the near position from the end hinged. Thus, the results obtained in present study show that the magnitude of dynamic critical loads, the load positions of minimum dynamic critical loads and the regions in which the dynamic critical loads are not defined depend on end conditions of arches.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.495-500
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• 2003

The effect of initial combined load on the lateral free vibration of arches is investigated. For the analysis, P-M interaction curves for the arches are obtained. The arches are circular arches which have constant cross-section and simply supported. Also, the arches are subjected both radial uniform distributed load which results in an axial compression on the cross-section and end moments that cause uniform bending action at the same time. All analysis are performed by finite element method based on Kang and Yoo's curved beam theory.

• Structural Engineering and Mechanics
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• 제13권6호
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• pp.713-730
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• 2002

This paper presents a finite element approach for determining the natural frequencies for planar inclined arches of various shapes vibrating in three-dimensional space. The profile of inclined arches, represented by undeformed centriodal axis of cross-section, is defined by the equation of plane curves expressed in the rectangular coordinates which are : circular, parabolic, sine, elliptic, and catenary shapes. In free vibration state, the arch is slightly displaced from its undeformed position. The linear relationship between curvature-torsion and axial strain is expressed in terms of the displacements in three-dimensional space. The finite element discretization along the span length is used rather than the total are length. Numerical results for arches of various shapes are given and they are in good agreement with those reported in literature. The natural frequency parameters and mode shapes are reported as functions of two nondimensional parameters: the span to cord length ratio (e) and the rise to cord length ratio (f).

• 대한치과교정학회지
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• 제14권1호
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• pp.93-101
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• 1984

Human dental arches are very various in their sizes and dimensions as well as forms, so, it is very difficult to describe the shape of human dental arches as a criterion, and, further, to construct the preformed arch wires fit to them. In this study for solving these problems, the shape of eighty Korean normal lower dental arches were studied, and nine theoretical two-parameter catenary curves were derived, which were representative of all of the sample. Test were conducted which demonstrated that these nine cattenary curves would correspond with a reasonable degree of accuracy to all of the dental arches, lower and upper.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.441-448
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• 1998

In this study, an explicit transient analysis program considering material and geometric nolinearities has been developed and used to analyze the dynamic behaviors of circular, parabolic, sinusoidal and catenary arches according to the change of shapes and boundary conditions. To understand dynamic behaviors of arches, first of all, the results of free vibration analysis for four kinds of arches are discussed. The results of transient analysis under impact loads we discussed in respect of boundary condition, change of height, and arch-shape. The dynamic behaviors of arches by nonlinear transient analysis considering both material and geometric nolinearities are also discussed.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.452-461
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• 2003

The effect of initial combined load on the lateral free vibration of arches is investigated. For the analysis, P-M interaction own for the arches are obtained. The arches are circular arches which have constant cross-section and simply supported. Also, the arches are subjected both radial uniform distributed load which results in an axial compression on the cross-section and end moments that cause uniform bending action at the same time. All analysis are performed by finite element method based on Kang and Yoo's curved beam theory.

• Structural Engineering and Mechanics
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• 제20권1호
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• pp.69-83
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• 2005

In many cases, underground structures are built using conventional above-grade structural systems to carry gravity load. This paper proposes the use of underground arches, termed "buried arches", to support gravity loads, wherein the horizontal thrust of the arch is equilibrated by soil pressure. Because the horizontal soil pressure increases with depth, the depth of the arch may be reduced as the depth below grade increases. Critical to the success of such an approach is a proper accounting of creep and shrinkage for arches made of reinforced concrete. This paper addresses the influence of equilibrium, creep, and shrinkage as they affect the design of the arch from a theoretical perspective. Several examples illustrate the use of buried arches for the design of underground parking structures.

• 한국강구조학회 논문집
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• 제18권4호
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• pp.427-436
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• 2006

고전 좌굴 이론의 경우 좌굴 발생전 아치의 거동을 선형으로 가정하며, 전좌굴 변형을 무시한다. 이러한 가정은 비대칭 좌굴이 발생하는 깊은 아치의 경우 타당한 것으로 알려져 있다. 하지만 아치의 라이즈가 낮아지는경우 전좌굴 발선형성은 무시할 수 없으며, 비대칭 좌굴 강도보다 대칭 좌굴 강도가 낮아져 아치는 대칭좌굴에 의해 강도가 결정될 수 있다. 본 연구는 아치의 비선형 지배 미분 방정식을 이용하여 양단 힌지를 갖는 낮은 포물선 아치의 거동에 관한 연구를 수행하고 이러한 결과를 유한 요소 해석을 이용하여 검증하였다. 마지막으로 양단 힌지를 갖는 낮은 포물선 아치의 대칭 좌굴 강도에 관한 근사식을 제안하였다.

• 한국환경보건학회지
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• 제29권2호
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• pp.77-79
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• 2003

뉴포트 어시장에서 채집한 볼락류인 Sebastes crameri로부터 17개체의 아가미 기생물을 발견하였다. 그중 9개체는 단생흡충류인 Trochopus australis이고 나머지 8개체는 요각류인 Neobrachiella robusta였다. 이 기생물의 가장 많이 발견되는 부위는 볼락류의 제 2 아가미새궁과 배측 후부였다. 단생류인 T. australis는 주로 제 2 아가미 새궁에서 요각류인 N. robusta는 제 1 아가미새궁에서 발견되었으나 요각류는 제 4 아가미새궁에서는 발견되지 않았다. 이번 연구에서 기생물의 아가미 부착은 주로 제 1, 2 새궁의 배후측에, 그러나 제 3, 4 아가미새궁의 전복측과 중앙에는 적게 분포되어 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.526-529
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• 2004

Arches are one of the most important basic structural units as well as the beams, columns and plates. Most complicated structures consist of only these basic units and therefore it is very attractive research subject to analysis both the static and dynamic behavior of such units including the arches. This study deals with the free vibration of arbitrary shaped arches. In order to obtain the exactly arch shape, which surveyed (x, y) of neutral axis of arbitrary shaped arches are compared to various shape of arch: circular, parabolic, sinusoidal, elliptic, spiral and cartenary. The differential equations governing free vibrations of arches are merely adopted in the open literature rather than deriving the equations in this study. The Taylor series method is used as the numerical differential scheme. The Runge-Kutta method and the Regula-Falsi method, respectively, are used to integrate the governing differential equations and to compute the natural frequencies It is expected that results obtained herein can be practically utilized in the fields of vibration control.