• 한국의류학회지
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• 제18권4호
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• pp.443-451
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• 1994

The bending rigidity of yarn is derived in terms of physicil and mechanical characteristics of its constituent fibers and yarns structural parametrs. Theoretical analysis shows that the twist correcti on factor for the bending rigidity of yarn decreases with increase of the ratio of Young's m()dulus to the shear modulus of the constituent fibers. Also, the bending rigidity of yarn decreases as the surface helix angle of yarn increases.

• 동력기계공학회지
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• 제6권2호
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• pp.24-32
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• 2002

A program is developed to analyze and design the frequency and rigidity of the corrugated plates with various corrugation shapes (the considered corrugation shapes are triangular and trapezoidal) and 36 kinds of boundary conditions using smeared theory. The system is consisted of input, solution and output routines, and its routine is made up pull-down menu type and run in Window basis using Visual Basic Language. The input routine helps the design engineers to make the input data user-friendly. The solution routine uses the homemade solver. In the output routine, automatic designs can be done using AutoCAD and Intent Tool package by interfacing the input data.

• 노동경제논집
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• 제37권2호
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• pp.1-47
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• 2014

한국노동패널 자료에 나타난 개인임금 자료를 1998년부터 2012년 기간에 대해 분석한 결과 명목임금은 매우 유연한 것으로 나타났다. 프로빗 분석 결과 명목임금이 삭감될 확률은 인플레이션이 낮을수록 그리고 실업률이 높을수록 높게 나타났으며, 다양한 경제 인구학적 집단에 따라 다르게 나타났다. 한편 고용노동부의 사업체 조사와 한국노동패널 조사 자료를 비교 분석한 결과 실질임금은 매우 경기순행적이며, 그 경기변동 상 유연성은 인플레이션의 역할이라기보다는 명목임금 자체가 경기순행적이기 때문인 것으로 나타났다. 이상의 발견들은 임금경직성을 예측하거나 혹은 임금경직성 가정에 의존하여 실업변동을 설명하고자 하는 모형들의 현실 설명력을 반감시킨다. 추가적으로 본고는 임금 및 근로시간 변수에 나타난 측정오차의 문제를 다루고 있다.

• 한국공간구조학회논문집
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• 제6권3호
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• pp.93-101
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• 2006

아파트의 온돌 바닥판은 콘크리트 바닥판위에 경량기포 모르타르, 완충재, 마감 모르터가 복층으로 시공되어 콘크리트 바닥판 상부의 시공방법 및 재료에 의한 구조적 거동에 대한 영향이 다르게 나타난다. 따라서 보다 합리적인 아파트의 콘크리트 적층 바닥판의 진동평가를 위해서는 시공방법 및 재료를 고려한 새로운 개선된 진동핵석 모델이 요구된다. 본 논문에서는 실제아파트의 적층으로 시공된 콘크리트 바닥판에 대한 보다 합리적인 진동해석 방법을 제안하고자 한다.

• Structural Engineering and Mechanics
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• 제28권3호
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• pp.281-294
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• 2008

In this paper, linear elastic isotropic structures under the effects of both stochastic operators and stochastic excitations are studied. The analysis utilizes the spectral stochastic finite elements (SSFEM) with its two main expansions namely; Neumann and Homogeneous Chaos expansions. The random excitation and the random operator fields are assumed to be second order stochastic processes. The formulations are obtained for the system solution of the two dimensional problems of plane strain and plate bending structures under stochastic loading and relevant rigidity using the previously mentioned expansions. Two finite element programs were developed to incorporate such formulations. Two illustrative examples are introduced: the first is a reinforced concrete culvert with stochastic rigidity subjected to a stochastic load where the culvert is modeled as plane strain problem. The second example is a simply supported square reinforced concrete slab subjected to out of plane loading in which the slab flexural rigidity and the applied load are considered stochastic. In each of the two examples, the first two statistical moments of displacement are evaluated using both expansions. The probability density function of the structure response of each problem is obtained using Homogeneous Chaos expansion.

• Steel and Composite Structures
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• 제41권5호
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• pp.713-730
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• 2021

The seismic performance of rigid steel frames is widely investigated, but that of semi-rigid (SR) steel frames are not studied extensively, especially for near-field earthquakes. In this paper, the performances of five and ten-story steel SR frames having different degrees of semi-rigidity are evaluated at four performance points in the four different deformation states, namely, the elastic, elasto-plastic, plastic, and near collapse states. The performances of the SR frames are measured by the response parameters including the maximum values of the top floor displacement, base shear, inter-story drift ratio, number of plastic hinges, and SRSS of plastic hinge rotations. These response parameters are obtained by the capacity spectrum method (CSM) using pushover analysis. The validity of the response parameters determined by the CSM is evaluated by the results of the nonlinear time history analysis (NLTHA) for both near and far-field earthquakes at different PGA levels, which are consistent with the performance points. Results of the study show that the plastic hinges of SR frame significantly increase in the range of plastic to near-collapse states for both near and far-field earthquakes. The effect of the degree of semi-rigidity is pronounced only at higher degrees of semi-rigidity. The predictions of the CSM are fairly well in comparison to the NLTHA.

• Journal of Advanced Marine Engineering and Technology
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• 제23권4호
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• pp.565-573
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• 1999

Hihg Tensile Steel enables to reduce the plate thickness comparing to the case when Mild Steel is used. From the economical view points this is very preferable since the reduction in the hull weight. however to use the High Tensile Steel effectively the plate thickness may become thin so that the occurrence of buckling is inevitable and design allowing plate buckling may be necessary. If the inplane stiffness of the plating decreases due to buckling the flexural rigidity of the cross sect6ion of a ship's hull also decreases. This may lead to excessive deflection of the hull girder under longitudinal bending. In these cases a precise estimation of plate's behavior after buckling is necessary and nonliner analysis of isolated and stiffened plates is required for structural sys-tem analysis. In this connection this paper discusses nonlinear behaviour of thin plate under thrust. Based on the analytical method elastic large deflection analysis of isolated plate is perform and simple expression are derived to evaluated the inplane rigidity of plates subjected to uniaxial compression.

• 한국강구조학회 논문집
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• 제16권1호통권68호
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• pp.1-10
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• 2004

본 논문에서는 수직 및 수평 브레이싱을 생략하고 I-형 거더를 가로보만으로 연결한 강합성 2-거더교에서 가로보의 적정 배치간격 및 소요 휨강성의 산정을 위한 연구를 수행하였다. 이를 위해 지간 40m의 단순교와 40+50+40m의 2차로 연속교를 예제교량으로 시산 설계하였다. 본 교량에 대해 중간가로보의 배치 간격과 휨강성을 매개변수로 하여 합성전 후 고정하중, 활하중, 풍하중 및 지진하중에 대한 해석을 수행하고 설계하중조합에 대한 응력 및 활하중 분배효과를 분석하였다. 한편, 강재 거더와 가로보의 격자구조에 대해 합성전 고정하중을 고려한 재료-기하 비선형해석으로부터 횡비틀림 좌굴강도를 평가하였다. 이상의 해석 결과를 토대로 지점부 및 중간가로보의 적정 배치 간격과 소요 휨강성을 제안하였다.

• 한국안전학회지
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• 제19권4호
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• pp.31-35
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• 2004

The A17075/CFRP multi-layered hybrid laminate material consists of the alternating A17075-T6 sheets and carbon/epoxy prepregs of M40 fade. The influence of volume fraction and fiber orientation of A17075/CFRP layer on flexural properties of A17075/CFRP laminate alternating A17075-T6 and carbon/epoxy prepreg was investigated. The results obtained from the experimental analysis are as follows: 1. In the $0^{\circ}$ fiber orientation, the mont of increase of the flexural rigidity was $20.5\%$ at the $26.5\%$ volume fraction and $38.0\%\;at\;the\;35.7\%$ volume fraction compared with the flexural rigidity level(20.0GPa) of the $10\%$ volume fraction of CFRP. 2. In the $\pm45^{\circ}$ fiber orientation the amount of decrease of the flexural rigidity was $23.5\%\;at\;the\;20.0\%$ volume fraction and $31.5\%\;at\;the\;33.3\%$ volume fraction compared with the flexural rigidity level of the $10\%$ volume fraction of CFRP. 3. In the $0^{\circ}$ fiber orientation, the flexural strength was 481.5MPa at the $10\%$ volume fraction of CFRP and 583.8MPa at the $26.5\%$ volume fraction and 653.7MPa at the $35.7\%$ volume faction. 4. In the $\pm45^{\circ}$ fiber orientation, the flexural strength was 354.0MPa at the $20.0\%$ volume fraction of CFRP and 340.5MPa at the $33.3\%$ volume fraction.

• Advances in Computational Design
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• 제4권4호
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• pp.327-342
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• 2019

Rehabilitation and retrofitting of structures designed in accordance to standard design codes is an essential practice in structural engineering and design. For steel structures, one of the challenges is to strengthen the panel zone as well as its analysis in moment-resisting frames. In this research, investigations were undertaken to analyze the influence of the panel zone in the response of structural frames through a computational approach using ETABS software. Moment-resisting frames of six stories were studied in supposition of real panel zone, different values of rigid zone factor, different thickness of double plates, and both double plates and rigid zone factor together. The frames were analyzed, designed and validated in accordance to Iranian steel building code. The results of drift values for six stories building models were plotted. After verifying and comparing the results, the findings showed that the rigidity lead to reduction in drifts of frames and also as a result, lower rigidity will be used for high rise building and higher rigidity will be used for low rise building. In frames with story drifts more than the permitted rate, where the frames are considered as the weaker panel zone area, the story drifts can be limited by strengthening the panel zone with double plates. It should be noted that higher thickness of double plates and higher rigidity of panel zone will result in enhancement of the non-linear deformation rates in beam elements. The resulting deformations of the panel zone due to this modification can have significant influence on the elastic and inelastic behavior of the frames.