• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.83-85
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• 2006

The purpose of this study is to evaluate the fatigue life at the rib weldment of generator shaft. In order to do it, the stress distributions at the weldment under design loading condition were evaluated using FEA and analytical approach. The fatigue strengths of the as welded and toe machined rib specimen were estimated using 3-points bending fatigue test. Based on the fatigue test results, the S-N curve far the rib weldment of the generator shaft with post treatment was established.

• 한국세라믹학회지
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• 제34권9호
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• pp.921-926
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• 1997

Two NbCx-C1-x/Y2O3/Ti sputter-coated Al2O3 substrates (L 5.5 cm$\times$W 0.5 cm) were diffusion bonded together using hot press method at 95$0^{\circ}C$ for 3 hours under 1 MPa of applied pressure. 4 points bending tests were used to evaluate the mechanical performance of these precracked laminate beams. Two types of mechanical responses were observed: crack penetration through the interface for x=0.75, 1 and crack deflection into an interface for x=0.25, 0.5. The Al2O3/NbCx-C1-x/Y2O3/Ti system suggested here has been proves to be effective for the thermokinetical stability and tailorability of the interfaces of Al2O3/Ti composites at 95$0^{\circ}C$.

• 한국방재학회 논문집
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• 제3권1호
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• pp.123-131
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• 2003

파형강관을 삽입하여 보강된 중공원형단면의 역학적 거동을 연구하기 위하여 직경 50cm, 길이 340cm의 시험체를 제작하였고, 3점 휨시험을 수행하였다. 하중재하는 파괴 또는 최대한변형이 발생할 때까지 느리게 증가시켰다. 시험하는 동안에 시험체 중앙의 휨방향 변위와 인장측과 압축측의 종방향 변위를 측정하였다. 측정데이타를 분석한 결과를 파형강관이 삽입되지 않은 등가단면에 대한 해석결과와 비교하였다. 비교결과, 중공 철근콘크리트 부재의 휨강성과 연성이 파형강관을 내부에 삽입함으로써 크게 향상시킬 수 있는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제1권2호
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• pp.103-116
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• 1993

Recently, engineering ceramics called as the 3 material have been concerned significantly with some excellent mechanical properties and many functions as new materials for high precision mechanical components and engineering parts for at large. Then, for designing engineering parts using engineering ceramics, bending strength value data with high reliability is more essential than any other mechanical properties. But, because of brittleness and structural characteristic, it is very hard to grind with conventional tools, and the generation of cracks and various defects of engineering ceramics parts during grinding machining process are serious problems. Thus, in present study, surface grinding experiments with various machining conditions using resin bond diamond wheels are carried out to obtain the most excellent guality of testpiece surface and optimum step of grinding process for the high efficient stock removal rate to save running time. As the results from grinding experiments and 3-points bending strength test of ground Al2O3 ceramics parts on Korean Standard, manufactured in our country and Japan, basic technology and know-how to develop the optimum grinding machining conditions and also high bending strength values with high reliability are obtained.

• Computers and Concrete
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• 제4권1호
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• pp.49-66
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• 2007

The objective of this paper is to provide experimental data on the propagation of curved crack-surfaces and the respective load-displacement diagrams for the validation of numerical models for cracking of concrete, subjected to three-dimensional stress states. To this end beam-shaped specimens are subjected to combined bending and torsional loading, leading to the formation of a spatially curved crack-surface. The experimental data contain the evolution of the load and of the strains at selected points in terms of the crack mouth opening displacement and the propagation of the crack surface.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.728-736
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• 2017

In this study, the bending behavior of cross-laminated timber (CLT) connected by nails were investigated. Especially, the load-carrying capacity of the nail-jointed CLT under out-of-plane bending was predicted by the lateral resistance of the used nails. Three-layer nail-jointed CLT specimens and a nail connection were manufactured by 30 mm (thickness) ${\times}$ 100 mm (width) domestic species (Pinus koraiensis) laminas and Ø$3.15{\times}82mm$ nails using a nail-gun. Shear test for evaluating the nail lateral resistance and bending test for evaluating the load-carrying capacity of the nail-jointed CLT under out-of-plane bending were carried out. As a result, two lateral resistance of the used nail, the 5% fastener offset value and the maximum value, were 913 N and 1,534 N, respectively. The predicted load-carrying capacity of the nail-jointed CLT by the 5% offset nail lateral resistance was similar to the yield points on the actual load-displacement curve of the nail-jointed CLT specimens. Meanwhile, the nail-jointed CLT specimens were not failed until the tension failure of the bottom laminas occurred beyond the maximum lateral resistance of the nails. Thus, the measured maximum load carrying capacities of the nail-jointed CLT specimens, approximately 12,865 N, were higher than the predicted values, 7,986 N, by the maximum nail lateral resistance. This indicates that the predicted load-carrying capacity can be used for designing a structural unit such as floor, wall and roof able to support vertical loads in a viewpoint of predicting the actual capacities more safely.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1118-1123
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• 2003

Based on the design requirements(size, strength, structure, weight, and etc.) for the rubber-tired AGT vehicle, carbody made of aluminum alloy is designed. The analysis of strength and stiffness is performed in the designed carbody, which results in the modification for optimal shapes and structures. It consists of a under frame, side frame, roof frame, end frame and forehead frame. After the carbody manufactured, tests are performed, which are vertical load test, longitudinal compressive load test, twisting load test, twisting natural frequency measurement, bending natural frequency measurement and 3 points supporting test. Results of them can guarantee a structural safety.

• 한국정밀공학회지
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• 제26권11호
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• pp.116-123
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• 2009

The elastic properties of core affect mechanical properties and deformation behaviours of the lightweight sandwich panel. The objective of the present paper is to estimate experimentally Young's and shear moduli of a core in internally structured boned (ISB) panel with woven metal as inner structures using the deflection theory of sandwich beam considered core stiffness. Three points bending experiments were performed to obtain force-deflection curves of the designed ISB panel in each material direction. The elastic and shear moduli of the core in each material direction were estimated from slopes and intercepts of relationships between compliance per the span length and square of the span length, respectively. The results of the estimation showed that the fabric technology of the woven metal affects the variation of the elastic properties in the core. Through the comparison of shear moduli and force-deflection curves of the proposed method and those without considering the core stiffness, it was shown that the core stiffness should be considered to estimate properly the Young's and shear moduli of ISB panels. Finally, the contribution ratio of bending and shear deflections of ISB panels to the total deflection was quantitatively examined.

• International Journal of Advanced Culture Technology
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• 제12권3호
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• pp.57-61
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• 2024

Back pain is a pain that occurs from the waist to the legs. If back pain continues, the quality of life is mentally and physically degraded. The purpose of this study is to implement comprehensive strategies through the application of medical information management for the mitigation of lumbago. This study was analyzed using interviews and surveys from Januanry 17 to March 22, 2024. It is classified as 43 members of the experimental group and 43 members of the control group. Low back pain symptoms and treatment were measured by a t-test before and after the application of medical information management. The results of this study are as follows. Firstly, in the experimental group, 67.4% of those who sat for more than 10 hours were significantly higher than 32.6% of those who sat for less than 9 hours a day(X²=3.19, p=.00). Secondly, the forward bending has been increased significantly from the average of 30.58 points before the application of medical information management to 46.27 points after the application(t=-1.65, p=.03). Thirdly, lumbago has been shown to decrease continuously since 6 days. Fourthly, stretching continued to rise significantly from 3 days after applying medical information management. The results of this paper will contribute to reducing symptoms in patients with lumbago.

• 콘크리트학회논문집
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• 제17권2호
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• pp.255-261
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• 2005

본 연구에서는 매년 많은 양의 석탄회 발생으로 인한 환경오염을 줄이고 천연자원의 채취와 고갈로 인한 문제를 극복하기 위해, 산업 폐기물의 건설재료로서의 재활용 가능성을 확보하기 위한 기초적인 연구자료를 제시하였다. 압축강도실험을 통하여 재료에 대한 탄성계수값을 측정하였으며, 3점 휨파괴시험으로부터는 파괴에너지, 초기노치비, 노치민감도등을 평가함으로써 파괴역학적 파라메타를 제안하였다. 실험 결과, 초기강도는 콘크리트에 비해 낮으나 장기강도에서는 비슷함을 볼 수 있었다 하지만 파괴강도가 증가함에 따라 취성적인 경향을 보이면서 파괴에너지값은 낮음을 알 수 있었다. 또한 하중-변위곡선과 하중-균열개구변위곡선의 형태는 모두 비슷한 형태를 띠고 있었으며, 재령이 증가할수록, 노치비는 작을수록 최대하중값이 커지면서 파괴시의 처짐은 감소함을 알 수 있다. 하지만 파괴강도가 커지면서 취성적인 경향으로 최대하중이후의 연화구간의 기울기가 급해짐을 볼 수 있었다. 따라서 연성의 확보에 대한 추가적인 보완연구가 진행되어진다면 충분히 건설재료로 사용 가능할 것으로 판단되어진다.