• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.1-7
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• 1990

A method is developed for solving the elastica of cantilever beam subjected to a tip point load and uniform load. The Bernoulli-Euler differential equation of deflected beam is used. The Runge-Kutta method and the Regula Falsi method are used to perform the integration of the differential eqution and to determine the horizontal deflection, respectively. The horizontal and vertical deflections of the free end, and the free-end rotations are calculated for a range of parameters representing variations in tip point load and uniform load. All results are presented in nondimensional forms. And some typical elastic are also presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.154-157
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• 1994

보는 토목, 건축, 기계, 선박, 항공 등 구조공학 분야에서 가장 기본이 되는 구조단위이므로 그에 대한 동적해석 특히 자유진동에 관한 많은 연구들이 발표되고 있다. 이제까지 이러한 연구들은 사항중으로 인한 정적 초기처짐의 영향을 고려하지 않은 논문들이다. 최근 재료과학의 발달로 고강도의 재료가 출현하고 따라서 세장비가 매우 큰 구조물의 시공이 가능하게 되어 정적 처짐이 다소 큰 구조물에서도 정적 안전성을 확보할 수 있게 되었다. 그러나 이러한 경우에 정적 초기처짐은 구조물의 동적거동에 영향을 줄 것으로 생각된다. 본 연구는 문헌[7]에서 유도된 편미분방정식을 이용하여 사하중에 의한 정적 초기처짐을 갖는 보의 자유진동을 지배하는 상미분방정식을 유도하고 이를 수치해석하여 고유진동수와 진동형을 산출하는데 연구목적이 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.325-328
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• 2008

This study is to investigate experimentally the long-term deflection of concrete beams with glass fiber reinforced polymer (GFRP) reinforcing bars subjected to the sustained flexural load for periods of up to 6 months. A total of four beams were tested. All beams were designed with net span of 2,700 mm and rectangular cross-section of 200 mm width and 300 mm depth. From the test results the time-dependent deflection of concrete beams with GFRP bars was about 40 to 70% of the initial deflection. As well as this paper compares the long-term deflection calculated by 440.1R-06 design guide and that of tested beams. The comparison indicated that the calculated long-term deflection overestimate the observed long-term deflection of concrete beams with FRP rebars.

• Journal of the KSME
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• v.23 no.6
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• pp.448-458
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• 1983

보의 처짐(deflection of beam) 및 부정정보(statically indeterminate beam)의 문제는 수문이나 압력용기등을 비롯한 각종 구조물의 강도계산에서 설계자가 자주 부딪치는 문제이다. 일반적으로 분포하중이나 집중하중 또는 집중 모우멘트가 작용하는 보, 특히 부정정 보의 경우 해석하기 쉬운 방법을 찾아 모우멘트-면적법, 중첩법, 3-모우멘트의 방정식등을 사용하여 반력이나 반력 모우멘트, 처짐량 등을 계산하고 있다. 그러나 이들 방식들은 일률적으로 어느 경우에나 적용하기에 적합한 것은 아니고 복잡한 각종 정리나 공식들을 사용하여야 하며 공액보(conjugated beam)의 반력을 구한다든가, 선도의 면적을 구하기 위하여 힘든 계산을 행하여야 하는 등 쉽지 않아, 부정정 보를 풀어야 할 경우가 발생할 때마다 좀 더 쉬운 접근방법이 없을까 하는 애로를 느껴왔다. 그러던 차 특이함수를 도입하여 문제의 해결을 시도하여 본 바, 복잡한 공식들을 외울 필요 없이 규칙적이고 일률적인 방법으로 쉽게 문제의 해결이 가능하기에 여기 간단히 풀이 방법을 소개하고자 한다.

• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.43-50
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• 2008

This paper presents experimental and analytical results on the long-term behavior of the reinforced recycled aggregate concrete beams under sustained loading. In this experimental program, three beams with different conditions of aggregates replacement (natural aggregate 100%, recycled coarse aggregate 100%, recycled fine aggregate 50%) were subjected to the sustained flexural loading that was a half of the nominal flexural capacity over a period of 1 year. The beam were designed with net span of 2,000 mm and rectangular cross-section of 170 mm width and 170 mm effective depth. The beams were instrumented and monitored to observe the change in the long-term behavior due to creep and shrinkage of concrete under sustained loading. The predictions of long-term deflection by ACI code, Branson, Mayer, Neville, EMM and AEMM were compared with the experimental results. From the experimental results, the reinforced concrete beams with recycled aggregates showed the same performance as that of a beam with natural aggregate. The proposed method to predict the long-term deflections of reinforced recycled aggregate concrete beams gives a good estimation for experimental results.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.201-206
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• 2015

이 논문에서는 역학적 지식파 EDISON 구조동역학 서버에서 지원하는 이공계 교육 및 연구용 시뮬레이션 프로그램 중 Co-rotational Plane Beam with Arbitrary Section을 이용하여 캔틸레버 보의 처짐을 기하 비선형적으로 해석한다. 또한 해석에 사용된 프로그램이 실제 교육에 적용이 가능한 지를 고찰함에 그 목적이 있다. 처짐을 해석하기 위하여 수계산, 프로그램을 이용하여 얻은 결과값을 비교하였고 캔틸레버 보의 변화 형상을 시각화 하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.184-192
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• 2010

The member deflection is one of the most important considerations for the serviceability evaluation of reinforced concrete (RC) structures, and the concept of the effective moment of inertia has been generally used for its estimation. However, the actual service load applied on an existing RC beam may not be easily obtained, for which the estimation of beam deflection by existing methods can be difficult to obtain. Therefore, based on the correlation between cracks and deflection in a RC beam, this study proposed a method to estimate the deflection of RC beams directly from the condition of cracks not using the actual loads acting on the member as its input data. The proposed method extensively utilized the relationships among sums of crack widths, average strains, and curvatures, and modification factors obtained from regression analysis were also introduced to improve its accuracy. The deflections of members were successfully estimated by the proposed method independent from applied loads, which was also easy to apply compared to the existing methods based on the effective moment of inertia.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.123-132
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• 2010

To overcome the drawback of currently available curved beam theories having non-symmetric thin-walled cross sections, a curved beam theory based on centroid-shear center formulation is presented for the spatially coupled free vibration and elastic analyses. For this, the displacement field is expressed by introducing displacement parameters defined at the centroid and shear center axes, respectively. Next the elastic strain and kinetic energies considering the thickness-curvature effect and the rotary inertia of curved beam are rigorously derived by degenerating the energies of the elastic continuum to those of curved beam. In order to illustrate the validity and the accuracy of this study, FE solutions using the Hermitian curved beam elements are presented and compared with the results by centroid formulation, previous research and ABAQUS's shell elements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.936-943
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• 2011

The effective moment of inertia revising the expression proposed by Branson has been used in ACI 440.1R-06 design guide for calculating deflections of FRP-reinforced concrete members. However, its adequacy has been questioned by several researchers. The propose of this study is to provide fundamental data for the rational design of deflection by the comparison of the experimental results obtained from twelve specimens with rectangular section and nine specimens with T-shaped section to the theoretical results. As a result, it found that calculated results for specimens with rectangular section were underestimated comparing to test results, while calculated results for specimens with T-shaped section were overestimated comparing to test results.

• Journal of the KSME
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• v.20 no.4
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• pp.296-302
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• 1980

이상에서 potential energy의 극소조건을 각종경우에 적용하여 재료역학의 해 또는 변형의 근사 해를 응용 예들을 통하여 구해 보았다. 이 해법은 을 받은 부재, 보(beam) 또는 순수 비틀림을 받는 엔형봉재의 경우, 부정정 문제에서 그 지지점들에서의 반력요소를 생각할 필요가 없기 때 문에 재료 역학적인 해법보다 더 간편하게 구해지고 있는 것을 볼 수가 있다. 또 보의 처짐 곡 선이 길이의 중앙면에 대하여 좌우 대칭형일 때에, 중앙단면에서의 최대처짐을 구하는데 삼각 함수의 근사처짐 곡선을 설정하므로써 실제 엄밀해에 가까운 근사값이 간단하게 구해질 수 있는 것을 보였다. 이 극소에너지 정리는 엔형단면이 아닌 각종 단면봉재의 비틀림 문제에서도 비틀림 응력함수를 도입하고, 경제조전을 만족하는 근사공력 함수방정식을 가정함으로써 간단하게 그 근사해를 구하는 데까지 직장할 수가 있다.