• Structural Engineering and Mechanics
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• 제35권1호
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• pp.67-82
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• 2010

The beam string structure (BSS) has been widely applied in large span roof structures, while no analytical solutions of BSS were derived for it in the existing literature. In the first part of this paper, calculation formulas of displacement and internal forces were obtained by the Ritz-method for the most commonly used arc-shaped BSS under the vertical uniformly distributed load and the prestressing force. Then, the failure mode of BSS was proposed based on the static equilibrium. On condition the structural stability was reliable, BSS under the uniformly distributed load would fail by tensile strength failure of the string, and the beam remained in the elastic or semi-plastic range. On this basis, the limit load of BSS was given in virtue of the elastic solutions. In order to verify the linear elastic and limit state solutions proposed in this paper, three BSS modal were tested and the corresponding elastoplastic large deformation analysis was performed by the ANSYS program. The proposed failure mode of BSS was proved to be correct, and the analytical results for the linear elastic and limit state were in good agreement with the experimental and FEM results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.603-608
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• 2008

It is well known that the topology optimization for plastic problem is not easy since the iterative analyses to evaluate the objective and cost function with respect to the design variation are very time-consuming. The finite element limit analysis is an efficient tool which is possible to predict collapse modes and sequential collapse loads of a structure considering not only large deformation but also plastic material behavior with moderate computing cost. In this paper, the optimum topology of a structure considering large and plastic deformation is obtained using the finite element limit analysis. To verify the constructed optimization code, topology optimizations of some typical problems are performed and the optimal topologies by elastic design and plastic design are compared.

• Earthquakes and Structures
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• 제16권5호
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• pp.575-588
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• 2019

Seismic design method based on bearing capacity has been widely adopted in building codes around the world, however, damage and collapse state of structure under strong earthquake can not be reflected accurately. This paper aims to present a deformation-based seismic design method based on the research of RC component deformation index limit, which combines with the feature of Chinese building codes. In the proposed method, building performance is divided into five levels and components are classified into three types according to their importance. Five specific design approaches, namely, "Elastic Design", "Unyielding Design", "Limit Design", "Minimum Section Design" and "Deformation Assessment", are defined and used in different scenarios to prove whether the seismic performance objectives are attained. For the components which exhibit ductile failure, deformation of components under strong earthquake are obtained quantitatively in order to identify the damage state of the components. For the components which present brittle shear failure, their performance is guaranteed by bearing capacity. As a case study, seismic design of an extremely irregular twin-tower high rise building was carried out according to the proposed method. The results evidenced that the damage and anti-collapse ability of structure were estimated and controlled by both deformation and bearing capacity.

• 한국안전학회지
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• 제17권4호
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• pp.146-152
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• 2002

The steel shows plastic deformation after the yield point exceeds. Because of overloads, the plastic deformation occurs at the interior support of a continuous bridge. The plastic deformation is concentrated at the interior support, and the permanence deformation at the interior support remains after loads pass. Because local yielding causes the positive moment at the interior support, it is called "auto moment". Auto moment redistributes the elastic moment. Because of redistribution, auto moment decreases the negative moment at the interior support of a continuous bridge. In this paper, the moment-rotation curve from Schalling is used. The Plastic rotation is computed by using Beam-line method, and auto moment is calculated based on the experiment curve. The design example is presented using limit state criterion.

• 한국산업융합학회 논문집
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• 제27권3호
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• pp.573-580
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• 2024

Recently, the special alloy, for instance, such as Monel and Inconel, is used for valves, bolt/nuts, and fittings in semiconductor facility, FCEV(fuel cell electric vehicle) and hydrogen gas station, to reduce the hydrogen embrittlement. Even though the Monel material has high cost, it is recommended to use for the cases of ultra high pressure, ultra high leak-proof and so on. The purpose of this study is to investigate the characteristics of Monel material within elastic limit through the comparative analysis when Monel material is extruded or drawn. As the results, the deformation of Monel material was increased as the number of pass was increased, further, the deformation of Monel material by drawing was larger than that by extrusion. In the safety factor, the case that load is less than 420kN, the plastic deformation due to drawing could be happened faster than that due to extrusion. However, the case of more than 420kN, it showed that the plastic deformation for extrusion and drawing was almost similar.

• 한국군사과학기술학회지
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• 제5권3호
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• pp.89-97
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• 2002

In this study, the effect of $\alpha$-phase morphology on the dynamic deformation behavior at ultra high strain rate was investigated by EBW(Explosive Bridge Wire) test. All of tests and analyses were conducted on three typical microstructures of Ti-6Al-4V alloy, i.e. equiaxed, widmanstatten and bimodal microstructures. The spall strength and HEL(Hugoniot Elastic Limit) of the specimens that have the thickness of 2mm and 4mm were highest with the bimodal microstructure. These results were similar with previous study which was performed by dynamic torsion test(Kolsky torsion test).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.773-776
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• 1997

This paper presents an investigation of the energy absorption of composite laminates during ballistic impact. Three components are responsible for the absorption of energy-the tensile failure of fiber, the elastic deformation of the composite, the delamination of composite laminates. The ballistic limit, V/sub 0/, of the laminates is determined using a previous model implemented to determine the energy absorption of the three components listed above. The size of the deformed zone during impact was estimated by an approximate solution for impacts on plates. The carbon/epoxy plates were examined for this research.

• Structural Engineering and Mechanics
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• 제90권4호
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• pp.391-401
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• 2024

The present study focuses on the effect of extension-bending coupling on the elastic stability (buckling) of laminated composite plates. These plates will be loaded under uni-axial or bi-axial in-plane mechanical loads, especially in the orthotropic or anti-symmetric cross-angle cases. The main objective is to find a limit where we can approximate the elastic stability behavior of angularly crossed anti-symmetric plates by the simple behavior of specially orthotropic plates. The contribution of my present study is to predict the explicit effect of extension-flexion coupling on the elastic stability of this type of panel. Critically, a parametric study is carried out, involving the search for the critical buckling load as a function of deformation mode, aspect ratio, plate anisotropy ratio and finally the study of the effect of lamination angle and number of layers on the contribution of extension-flexure coupling in terms of plate buckling stability. We use first-order shear deformation theory (FSDT) with a correction factor of 5/6. Simply supported conditions along the four boundaries are adopted where we can develop closed-form analytical solutions obtained by a Navier development.

• 대한토목학회논문집
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• 제9권1호
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• pp.89-95
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• 1989

다져진 흙의 공시체에 최대 10만회 까지 반복하중(反復荷重)을 가하였을 때 잔류변형(殘溜變形) 및 탄성변형(彈性變形) 그리고 반복후(反復後) 일축압축시험을 행하여 응력(應力)-변형율(變形率) 관계등(關係等)을 검토하였으며, 여기에 영향을 미치는 함수비(含水比), 밀도(密度), 반복회수(反復回數), 반복하중등(反復荷重等)에 대해서 고찰(考察)하였다. 반복회수(反復回數)에 따른 변형(變形)의 증가율(增加率)은 소성한계(塑性限界)를 기준으로 함수비의 정도에 따라 크게 변화 하였으며, 반복하중(反復荷重)을 받은후(後) 구한 탄성변형계수(彈性變形係數)로부터 흙의 초기접선계수(初期接線係數)의 추정(推定)이 가능 하였다.

• 한국농공학회논문집
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• 제48권4호
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• pp.51-57
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• 2006

This study was carried out to investigate the soil water characteristic curve and prediction of void ratio with net stress and matric suction using the linear elastic and volumetric deformation analysis method on unsaturated silty. The unsaturated soil tests were conducted using a modified oedometer cell and specimens were prepared at water content 2 times of liquid limit and required void ratio. The axis translation technique was used to create the desired matric suctions in the samples. It is shown that soil water characteristic curve and volumetric water content were affected significantly by preconsolidation pressure. As a matric suction increases, the reduction ratio of void ratio was shown to considerably small. Also, the predicted and measured void ratio for unsaturated soils using the linear elastic and volumetric deformation analysis showed good agreement as net stress and matric suction increases.