• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.942-947
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• 2004

The differential equations governing free, in-plane vibrations of stepped non-circuiar arches are derived as nondimensional forms including the effects of rotatory inertia, shear deformation and axial deformation. The governing equations are solved numerically to obtain frequencies and mode shapes. The lowest four natural frequencies and mode shapes are calculated for the stepped parabolic arches with hinged-hinged, hinged-clamped, and clamped-clamped end constraints. A wide range of arch rise to span length ratios, slenderness ratios, section ratios, and discontinuous sector ratios are considered. The effect of rotatory inertia and shear deformation on natural frequencies is reported. Typical mode shapes of vibrating arches are also presented.

• 한국소음진동공학회논문집
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• 제20권2호
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• pp.144-152
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• 2010

This paper deals with free vibrations of the tapered circular arches with constant volume, whose cross sectional shape is the solid regular polygon. Volumes of the objective arches are always held constant regardless shape functions of the cross-sectional depth. The shape functions are chosen as the linear, parabolic and sinusoidal ones. Ordinary differential equations governing free vibrations of such arches are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various arch parameters such as rise ratio, section ratio, side number, volume ratio and taper type are reported in tables and figures.

• 한국소음진동공학회논문집
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• 제18권2호
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• pp.215-223
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• 2008

The differential equations governing free vibrations of the elastic arches with hollow section are derived in polar coordinates, in which the effect of rotatory inertia is included. Natural frequencies is computed numerically for parabolic arches with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and reference are made to validate theories and numerical methods developed herein. The lowest four natural frequency parameters are reported, with the rotatory inertia, as functions of three non-dimensional system parameters: the breadth ratio, the thickness ratio and the rise to span length ratio.

• 소음진동
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• 제3권4호
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• pp.331-339
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• 1993

The main purpose of this paper is to present an analytical method for free vibration of arches with thickness varying in a discontinuous fashion. The ordinary differential equations governing the free vibration of these arches are derived as nondimensional forms including the effect of rotatory inertia. The governing equation are solved numerically for the circular and sinusoidal arches with hinged-hinged-hinged end clamped-clamped end constraints. As the numerical results, the effect of rotatory inertia on the natural frequencies is reported. The lowest four natural frequencies are presented as the functions of four nondimensional system parameters; the rise to span length ratio, the slenderness ratio, the section ratio and the ratio of discontinuous section.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.213-218
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• 2000

This paper deals with the free vibrations of shallow arches resting on elastic foundations. Foundations are assumed to follow the hypothesis proposed by Pasternak. The governing differential equation is derived for the in-plane free vibration of linearly elastic arches of uniform stiffness and constant mass per unit length. Sinusoidal arches with hinged-hinged and clamped-clamped end constraints are considered in analysis. The frequency equations (lowest symmetical and antisymmetrical natural frequency equations) are obtained by Galerkin's method. The effects of arch rise, Winkler foundation parameter and shear foundation parameter on the lowest two natural frequencies are investigated.

• Structural Engineering and Mechanics
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• 제4권1호
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• pp.9-23
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• 1996

The behaviour of elasto-plastic planar arches subjected to dynamic loads in presented. The governing equations are formulated through the dynamic equations and compatibility conditions. The latter is established by applying the generalized conjugate segment analogy. Bending moments at the nodes and axial forces in the members are considered as primary variables in the elastic regime. They are supplemented by the rotations at the nodes and dislocations in the elements when plastic hinges occur. Newmark-${\beta}$ method is adopted in the time marching process. The interaction diagram of each element is treated as the yield surface for the element and the associated flow rule is enforced as plastic flow occurs. The method provides good prediction of dynamic response of elasto-plastic arches while requiring small core storage and short computer time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1254-1259
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• 2001

This paper deals with the free vibrations of circular arches with variable cross-section. The differential equations governing free, in-plane vibrations of tapered circular arches, including the effects of rotatory inertia, shear deformation and axial deformation, are derived and solved numerically to obtain frequencies and mode shapes. Numerical results are calculated for the quadratic arches with hinged-hinged and clamped-clamped end constraints. Three general taper types for a rectangular section are considered. The lowest four natural frequencies and mode shapes are presented over a range of non-dimensional system parameters： the subtended angle, the slenderness ratio and the section ratio.

• 한국강구조학회 논문집
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• 제16권1호통권68호
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• pp.81-89
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• 2004

구조물과 같은 아치의 진동해석은 많은 산업분야에서 다양하게 적용되기 때문에 공학적 문제에 중요한 주제이다. 특히 변화하는 단면형상을 가지는 아치는 질량이나 강도를 최적화 하거나 특별한 구조물이나 요구조건들을 만족하기 위해서 폭넓게 사용되어 진다. 최근에는 일반화 미분구적법(GDQM)이나 미분변환법(DTM)은 각각 Shu와 Zou에 의해서 제안이 되었다. 연구에서는 변화하는 단면형상을 가지는 아치의 진동해석이 일반화 미분구적법과 미분변환법을 적용하였다. 변화하는 단면형상을 가지는 아치에 대하여 지배방정식이 유도되어졌으며, 미분변환과 일반화 미분구적법의 개념이 간단히 소개되었다. 변화하는 단면형상을 가지는 아치의 무차원화된 고유진동수가 다양한 경계조건에 대해서 구해졌으며, 이러한 방법들에 의해서 얻어지는 결과들은 선행연구와 비교 되어졌다. 일반화 미분구적법과 미분변환법은 변화하는 단면형상을 가지는 아치의 진동문제를 해석함에 있어서 빠른 수렴, 정확도, 효율성, 유효성을 보인다.

• 전산구조공학
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• 제7권1호
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• pp.69-81
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• 1994

본 논문은 형상의 비선형성을 고려한 큰 동하중을 받는 낮은 원호아치의 동적해석에 관한 연구이다. 따라서 낮은 원호아치를 대상으로 동적 비선형 해석을 수행하고 임계좌굴하중을 구할 수 있는 컴퓨터 프로그램을 개발하는데 주안점을 둔다. 형상의 비선형성은 Lagrangian 운동좌표를 고려하여 해석하였으며 비선형 동적 운동방정식을 풀기 위하여 유한요소법을 사용하였다. 개발된 프로그램을 사용하여 만재 방사형 등분포하중을 받는 원호아치를 해석하고, 그 결과를 다른 연구결과와 비교하여 검증하였다. 또한 여러가지의 형상의 아치에 대한 좌굴 해석을 실시하여 임계좌굴하중을 구하였으며 기존의 연구와 비교하여 정확성을 확인하였다. 모형해석을 통해서 큰 동하중을 받는 원호아치는 기하학적 비선형 거동을 고려하여 해석되어야 하며 아치가 낮아질수록 좌굴발생 가능성이 높아짐을 알 수 있다.

• Archives of Reconstructive Microsurgery
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• 제18권2호
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• pp.79-83
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• 2009

Purpose: Avulsion injuries of digits have been presented for a long time as complex management problems. Despite of microsurgical advances, it is difficult to achieve good functional results and their management remains somewhat controversial. However, in a finger there are three transverse digital palmar arches. The middle and distal transverse digital palmar arches are consistently large(almost 1 mm) and may be used for arterial vessel repairs either proximally or distally, depending on the length and direction needed. 39-year-old man presented with avulsion amputation of the ulnar three digits, was operated using only arterial anastomosis with rerouting the transverse digital palmar arches. Methods: Replantation was performed using the artery-only technique. Because the digital arteries had been damaged, we did that the transverse digital palmar arches were transposed in an inverted Y to I configuration and were lengthened with rerouting them for the purpose of direct anastomosis of the digital artery. Venous drainage was provided by an external bleeding method with partial nail excision and external heparin irrigation. Results: The authors conclude that complete avulsion amputations with only soft tissue at the distal to insertion of the flexor digitorum superficialis tendon were salvageable with acceptable functional results. All three fingers survived. Conclusion: With technical advancements, the transverse digital palmar arches play an important role for finger amputation. Three digital palmar arches give us additional treatment option for the finger amputation. In this case, replantation with only-arterial anastomosis was successful and we obtained good aesthetic and functional outcome.