• 한국구조물진단유지관리공학회 논문집
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• 제26권6호
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• pp.193-203
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• 2022

본 연구는 국내에서 주로 사용되는 강구조 보-기둥 접합상세와 논스캘럽접합상세의 내진성능을 비교하기 위해 실대형 정적반복실험과 실험과 동일한 모델링 통한 FEM해석을 진행하였다. 정량적인 수치비교를 위해 이전연구에서 사용된 변형률집중지수와 모멘트전달효율을을 인용하였다. 보 웨브의 용접면적 감소에 따라 플랜지 부분의 변형률이 증가되어 회전각에 따른 소성변형능력이 감소되거나 취성파단이 일어나는 현상을 보였다. 해석결과와 실험결과 비교시 H형 전체단면적에 대한 웨브 용접비가 60%이하로 떨어질 경우 취성파단이 일어날 가능성이 높아지는 경향이 나타났다.

• 대한토목학회논문집
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• 제3권4호
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• pp.109-122
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• 1983

본(本) 연구(硏究)에서는 전단변형(剪斷變形)(Shear deformation)과 회전관성(回轉慣性)(Rotatory inertia)의 영향(影響)을 고려(考慮)한 4절점(節點) 8자유도(自由度)를 갖는 Timoshenko 보 요소(要素)(TB4)를 3차원(次元) 연속체(連續體)로부터 유도(誘導)하고 있다. TB4보 요소(要素)는 3차(次) 보간함수(補間凾數)(Interpolation function)로 표시(表示)되는 연직(鉛直)처짐(Transverse deflection) W와 평면회전(平面回轉)(Plane rotation) ${\theta}$를 절점(節點)의 자유도(自由度)로 취(取)하고 있다. TB4요소(要素)의 강도(剛度)매트릭스와 질량(質量)매트릭스는 보의 운동방정식(運動方程式)을 Galerkin 가중잔차법(加重殘差法)(Weighted residual method)으로 Discretization하여 3개(個)의 Gauss점(點)을 이용(利用)한 RSI(Reduced shear integration)기법(技法)에 의한 수치적분(數値積分)으로 구해진다. TB4보 요소(要素)의 정확성(正確性)과 수감상태(收歛狀態)를 고찰(考察)하기 위하여 여러 가지 예제(例題)를 해석(解析)한 결과(結果), 보의 L/h 비(比)에 관계없이 보의 정적해석(靜的解析)(Static analysis)이라 자유진동해석(自由振動解析)(Free vibration analysis)에 있어서 TB4보 요소(要素)는 다른 Timoshenko보 요소(要素)들 보다 월등(越等)히 우수(優秀)한 정확도(正確度)와 수감현상(收歛現象)을 보여 주고 있다.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.471-477
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• 2015

In this study, the property of crack propagation and growth at high tension steel plate existed with center crack is investigated. The behaviors of fracture mechanics due to existence or not of hole near the center crack in specimen and the length of crack length are investigated when the load is applied at the one side end of specimen. Stress, deformation and deformation of this specimen are evaluated through simulation analysis. By the analysis results at this study, stress intensity factors are obtained. The damage happened at machine or structure with crack or defect can be estimated on the basis of study results.

• Steel and Composite Structures
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• 제6권1호
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• pp.33-53
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• 2006

The rotational behaviour of bolted extended end plate beam-to-column connections is evaluated in the context of the component method. The full moment-rotation response is characterized from the force-deformation curve of the individual joint components. The deformability of end plate connections is mostly governed by the bending of the column flange and/or end plate and tension elongation of the bolts. These components form the tension zone of the joint that can be modelled by means of "equivalent T-stubs". A systematic analytical procedure for characterization of the monotonic force-deformation behaviour of individual T-stub connections is proposed. In the framework of the component method, the T-stub is then inserted in the joint spring model to generate the moment-rotation response of the joint. The procedures are validated with the results from an experimental investigation of eight statically loaded extended end plate bolted moment connections carried out at the Delft University of Technology. Because ductility is such an important property in terms of joint performance, particularly in the partial strength joint scenario, special attention is given to this issue.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1712-1721
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• 2004

A method of measuring the thermal diffusivity of semi-infinite solid material at room temperature using photothermal displacement is proposed. In previous works, within the constant thickness of material, the thermal diffusivity was determined by the magnitude and phase of deformation gradient as the relative position between the pump and probe beams. In this study, however, a complete theoretical treatment of the photothermal displacement technique has been performed for thermal diffusivity measurement in semi-infinite solid materials. The influence of parameters, such as, radius and modulation frequency of the pump beam and the thermal diffusivity, was studied. We propose a simple analysis method based on the zero -crossing position of real part of deformation gradient and the minimum position of phase as the relative position between two beams. It is independent of parameters such as power of pump beam, absorption coefficient, reflectivity, Poisson's ratio, and thermal expansion coefficient.

• Steel and Composite Structures
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• 제19권5호
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• pp.1145-1165
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• 2015

A behavior model for screw connections is developed to provide a better representation of the nonlinear response of thin steel plate shear walls (TSPSWs) with infill plates attached to the boundary frame members via self-drilling screws. This analytical representation is based on the load-bearing deformation relationship between the infill plate and the screw threads. The model can be easily implemented in strip models of TSPSWs where the tension field action of the infill plates is represented by a series of parallel discrete tension-only strips. Previously reported experimental results from tests of two different TSPSWs are used to provide experimental validation of the modeling approach. The beam-to-column connection behavior was also included in the analyses using a four parameter rotational spring model that was calibrated to a test of an identical frame as used for the TSPSW specimens but without the infill plates. The complete TSPSW models consisting of strips representing the infill plates, zero length elements representing the load-bearing deformation response of the screw connection at each end of the strips and the four parameter spring model at each beam-to-column connection are shown to have good agreement with the experimental results. The resulting models should enable design and analysis of TSPSWs for both new construction and retrofit of existing buildings.

• 한국지진공학회논문집
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• 제26권5호
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• pp.203-209
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• 2022

A simplified method for earthquake response analysis of a rectangular liquid storage tank is proposed with fluid-structure interaction considered. In order to simplify the complex three-dimensional structural behavior of a rectangular liquid storage tank, it is assumed that structural deformation does not occur in the plane parallel to the direction in which the earthquake ground motion is applied but in the plane perpendicular to the direction. The structural deformation is approximated by combining the natural modes of the simple beam and the cantilever beam. The hydrodynamic pressure, the structure's mass and stiffness, and the hydrodynamic pressure's added mass are derived by applying the Rayleigh-Ritz method. The natural frequency, structural deformation, pressure, effective mode mass, and effective mode height of the rectangular liquid storage tank are obtained. The structural displacement, hydrodynamic pressure, base shear, and overturning moment are calculated. The seismic response analysis of an example rectangular liquid storage tank is performed using the proposed simplified approach, and its accuracy is verified by comparing the results with the reference solution by the finite element method. Existing seismic design codes based on the hydrodynamic pressure in rigid liquid storage tanks are observed to produce results with significant errors that cannot be ignored.

• Steel and Composite Structures
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• 제41권6호
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• pp.805-820
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• 2021

In this research, the buckling and free vibration of three-phase carbon nanotubes/ fiber/ polymer piezoelectric nanocomposite face sheet sandwich microbeam with microsensor and micro-actuator surrounded in elastic foundation based on modified couple stress theory (MCST) is investigated. Three types of porous materials are considered for sandwich core. Higher order (Reddy) and sinusoidal shear deformation beam theories are employed for the displacement fields. Sinusoidal surface stress effects are extracted for sinusoidal shear deformation beam theory. The equations of motion are derived by Hamilton's principle and then the natural frequency and critical buckling load are obtained by Navier's type solution. The determined results are in good agreement with other literatures. The detailed numerical investigation for various parameters is performed for this microsensor-microactuator. The results reveal that the microsensor-microactuator enhanced by increasing of Skempton coefficient, carbon nanotubes diameter length to thickness ratio, small scale factor, elastic foundation, surface stress constants and reduction in porous coefficient, micro-actuator voltage and CNT weight fraction. The valuable results can be expedient for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1989년도 봄 학술발표회 논문집
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• pp.50-55
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• 1989

Piping systems are composed of pipes with various thickness, diameter and length. Accurate analysis of a piping system requires a complicated three dimensional finite element model and a computer system with large memory size, while simplified models result in system response prediction with deteriorated accuracy. An efficient analysis model for piping systems is proposed in this study. The proposed model is developed by introducing a joint model which accounts for the behavior of a pipe connection. Pipes are represented by beam elements and the effect of local deformation of pipe connections are replaced by joint element deformations. The proposed model which is as simple and efficient as a beam model can be used to obtain piping system response with accuracy close to that of a finite element model.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.76-79
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• 2005

Bending deformation and energy absorption characteristics of aluminum-composite hybrid tube beams have been analyzed for improvement in the bending performance of aluminum space frame by using experimental tests combined with theoretical and finite element analyses. Hybrid tube beams composed of glass fabric/epoxy layer wrapped around on aluminum tube were made in autoclave with the recommended curing cycle. Basic properties of aluminum material used for initial input data of the finite element simulation and theoretical analysis were obtained from the true stress-true strain curve of specimen which had bean extracted from the Al tube beam. A modified theoretical model was developed to predict the resistance to the collapse of hybrid tube beams subjected to a bending load. Theoretical moment-rotation angle curves of hybrid tube beams were in good agreement with experimental ones, which was comparable to the results obtained from finite element simulation. Hybrid tube beams strengthened by composite layer on the whole web and flange showed an excellent bending strength and energy absorption capability.