• 한국화재소방학회논문지
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• 제26권3호
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• pp.100-105
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• 2012

본 연구에서는 수계소화설비 가압송수장치의 파이프라인에 대한 내진설계를 수행하였다. 내진해석에 필요한 내진설계용 스펙트럼에 대응하는 인공지진 진동파형을 작성하였고, 작성된 인공지진 진동에 대한 응답 스펙트럼 가속도를 결정하여 등가정적하중을 결정하였다. 내진설계를 위한 공학적 기반을 구축하였으며, 수계 및 가스계 파이프 시스템의 내진설계를 위한 등가정적해석법을 제시하였다. 또한 본 연구의 결과로부터 수계설비의 파이프라인뿐만 아니라 소방설비의 내진설계 및 성능평가에 응용할 수 있는 기틀을 마련하였다. 향후 진도규모 및 지반종류에 따른 추가적인 연구가 수행된다면 소방시스템의 신뢰성 향상과 안전성 제고, 성능위주설계가 이루어질 수 있을 것으로 본다.

• Coupled systems mechanics
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• 제12권5호
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• pp.461-479
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• 2023

The paper deals with the finite element modelling of the free vibration and structural behavior of a particular four-floor reinforced concrete structure subjected to static equivalent seismic loads and supported by a shallow foundation system called SNSF (Spider Net System Footing). The two FE models are a simple 2D Matlab model and a detailed 3D model based on solid elastic elements using Altairworks (Hypermesh and Optistruct). Both models can simulate the soil structure interaction. We concentrate on the behavior of a representative cell involving two columns on five levels. The influence of the boundary conditions on the external vertical planes of the domain are duly studied. The Matlab model appears relevant for a primary estimation of frequencies and stiffness of the whole structure under vertical and lateral loads.

• 대한기계학회논문집A
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• 제24권1호
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• pp.38-51
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• 2000

The study on the mechanical behavior of a spot-welded specimen is largely divided into the quasi-static overload failure analysis and the fatigue failure prediction. The main issue in an overload analysis is to examine the critical loads, thereby providing a generalized overload failure criterion. As the welding spot forms a singular geometry of an external crack type, fatigue failure of spot-welded specimens can be evaluated by means of a fracture parameter. In this study, we first present the limit loads of 4 representative types of single spot-welded specimens in terms of the base metal yield strength and specimen geometries. Recasting the load vs. fatigue life relationships experimentally, obtained here, we then predict the fatigue life of spot-weld specimens with a single parameter denoted the equivalent stress intensity factor. This crack driving parameter is demonstrated to successfully describe the effects of specimen geometry and loading type in a comprehensive manner. The suggested fatigue life formula for a single spot weld can play a key, role in the design and assessment of spot-welded panel structures, in that the fatigue strength of multi-spots is eventually determined by the fatigue strength of each single spot.

• 한국산학기술학회논문지
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• 제9권6호
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• pp.1500-1505
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• 2008

본 논문은 원자력 내진등급 IIA 글로브 밸브의 지진하중에 대한 구조 건전성을 평가하였다. 밸브 구조물을 3차원 모델링하여 유한요소법을 사용하여 모달 해석 및 등가 정적 응력해석을 수행하였다. 모달 해석 결과 밸브 구조물은 충분히 강건하여 등가 정적해석이 가능하였고 해석에서 구한 응력들을 조합하여 원자력 규격집에서 제시한 허용응력과 비교하여 밸브의 구조 건전성을 판단하였다. 모든 지진하중에 대한 밸의 구조물에서의 응력은 허용값 보다 작게 분포하므로 구조적 건전성을 유지한다고 평가할 수 있다.

• Steel and Composite Structures
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• 제7권4호
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• pp.339-354
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• 2007

Arched Corrugated Steel Roof (ACSR) is a kind of thin-walled steel shell, composing of arched panels with transverse small corrugations. Four full-scale W666 ACSR samples with 18m and 30m span were tested under full and half span static vertical uniform loads. Displacement, bearing capacities and failure modes of the four samples were measured. The web and bottom flange in ACSR with transverse small corrugations are simplified to anisotropic curved plates, and the equivalent tensile modulus, shear modulus and Poisson's ratio of 18m span ACSR were measured. Two 18 m-span W666 ACSR samples were analyzed with the Finite Element Analysis program ABAQUS. Base on the tests, the limit bearing capacity of ACSR is low, and for half span loading, it is 74-75% compared with the full span loading. When the testing load approached to the limit value, the bottom flange at the sample's bulge place locally buckled first, and then the whole arched roof collapsed suddenly. If the vertical loads apply along the full span, the deformation shape is symmetric, but the overall failure mode is asymmetric. For half span vertical loading, the deformation shape and the overall failure mode of the structure are asymmetric. The ACSR displacement under the vertical loads is large and the structural stiffness is low. There is a little difference between the FEM analysis results and testing data, showing the simplify method of small corrugations in ACSR and the building techniques of FEM models are rational and useful.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.408-413
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• 2004

High speed planning boats also have been required more and more the rational strength analysis and evaluation for the optimal structural design in respect of the structural lightness according to the high speed trend. Even though the suggestion of the simple type equation for the equivalent dynamic pressure is reasonable to design the scantling of ship structure conveniently, many research activities for more reasonable improvement of the simple design pressure, have been continued to suggest the more accurate equivalent static description of tire structural response such as the deflection and stress of hull structure. In this research, we focus on the aluminum bottom stiffened plate structure in which structural scantling is mainly depend on the local loads such as dynamic or impact pressure without other load effects and structural response for the simple dynamic equivalent pressure was investigated through the structural analysis. In order to investigate the structural response of the bottom stiffened plate structure subjected to the dynamic equivalent design pressure, linear and nonlinear structural analysis of the bottom stiffened plate structure of 4.3 ton aluminum planning boat was performed based on the equivalent static applied loads which were derived from the KR regulation and representative one among various dynamic equivalent pressure equations. From above analysis results, we found that the response such as deflection and stress of plate member was similar with the response results of one plate member model with fixed boundary, which was published previous paper and in case of KR design loading, all response of stiffened plate structure were within elastic limit. Through the nonlinear analysis, nearly elastic behavior including the slight geometrical nonlinear response was dominant but plastic local zone was appeared at $85\%$ limit load. Therefore, we can say that through tire linear and nonlinear analysis, this stiffened plate member has no structural strength problem based on the yield criteria in case within $60\%$ limit load except the other strength point of view such as the fatigue and buckling problem.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2011년도 정기 학술대회
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• pp.218-221
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• 2011

본 연구에서는 추계학적 해석을 통하여 구한 교량의 동적 변위와 동일한 변위를 발생시키는 등가 정적 버페팅 하중을 구하는 방법을 제시하고, 단순 양단 캔틸레버에 적용하여 타당성을 검증하였다. 모드 형상이 복잡한 사장교의 경우에 2개 이상의 모드를 포함해야 정확도를 높일 수 있는 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제39권3호
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• pp.427-447
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• 2011

The progressive collapse phenomenon is generally regarded as dynamic. Due to the impracticality of nonlinear dynamic computations for practitioners, an interest arises for the development of equivalent static pushover procedures. The present paper proposes a methodology to identify such a procedure for sudden column removals, using energetic evaluations to determine the pushover loads to apply. In a dynamic context, equality between the cumulated external and internal works indicates a vanishing kinetic energy. If such a state is reached, the structure is sometimes assumed able to withstand the column removal. Approximations of these works can be estimated using a static computation, leading to an estimate of the displacements at the zero kinetic energy configuration. In comparison with other available procedures based on such criteria, the present contribution identifies loading patterns to associate with the zero-kinetic energy criterion to avoid a single-degree-of-freedom idealisation. A parametric study over a family of regular steel structures of varying sizes uses non-linear dynamic computations to assess the proposed pushover loading pattern for the cases of central and lateral ground floor column failure. The identified quasi-static loading schemes are shown to allow detecting nearly all dynamically detected plastic hinges, so that the various beams are provided with sufficient resistance during the design process. A proper accuracy is obtained for the plastic rotations of the most plastified hinges almost independently of the design parameters (loads, geometry, robustness), indicating that the methodology could be extended to provide estimates of the required ductility for the beams, columns, and beam-column connections.

• Geomechanics and Engineering
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• 제2권2호
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• pp.125-140
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• 2010

Slope stability analysis of the right abutment of a railway bridge proposed at about 350 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India is presented in this paper. The site is located in a highly active seismic zone. The rock slopes are intensely jointed and the joint spacing and orientation are varying at different locations. Static slope stability of the rock slope is studied using equivalent continuum approach through the most commonly used commercial numerical tools like FLAC and SLOPE/W of GEOSTUDIO. The factor of safety for the slope under static conditions was 1.88 and it was reduced by 46% with the application of earthquake loads in pseudo-static analysis. The results obtained from the slope stability analyses confirmed the global stability of the slope. However, it is very likely that there could be possibility of wedge failures at some of the pier locations. This paper also presents the results from kinematics of right abutment slope for the wedge failure analysis based on stereographic projections. Based on the kinematics, it is recommended to flatten the slope from 50o to 43o to avoid wedge failures at all pier locations.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.347-361
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• 2023

This research aims to assess the behavior of reinforced concrete (RC) residential buildings when moment-resisting frames (MRFs) are used as the lateral resisting system. This investigation was conducted using MIDAS Gen v.19.0. Buildings with various plan footprints (Square, Rectangular, Circular, Triangular, and Plus-Shaped), and different heights (15 m, 30 m, 45 m, and 60 m) are investigated. The defined load cases, the equivalent static lateral load pattern, and the response spectrum function were defined as stated by the American Standard (ASCE 7-16), the 1997 Uniform Building Code (UBC97), the Egyptian Code for Loads (ECP-201), and the European Standard (EC8). Extensive comparisons of the results obtained by the different codes (including the story displacement, the story drift, and the base shear) were undertaken; to assess the response of moment-resisting multi-story framed buildings under lateral loads. The results revealed that, for all study cases under consideration, both ECP-201 and EC8 gave smaller base shear, displacement, and drift by one third to one fourth, around one fourth, around one fifth, respectively for both the ELF and RSA methods if compared to ASCE 7-16 and UBC97.