• 한국안전학회지
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• 제18권4호
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• pp.1-7
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• 2003

The front-end side members of vehicles(spot welded hat and double hat shaped section members) absorb most of the impact energy in a case of front-end collision. In this paper, specimens with various spot weld pitches have been tested with a high impact velocity of 7.19m/sec(impact energy of 1034J). The axial impact collapse simulation on the sections has been carried out to review the collapse characteristics of these sections, using an explicit finite element code, LS-DYNA3D. Comparing the results with experiments, the simulation has been verified; the energy absorbing capacity is analyzed and an analysis method is suggested to obtain exact collapse loads and deformation collapse modes.

• 한국강구조학회 논문집
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• 제20권1호
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• pp.205-213
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• 2008

SM570TMC 강재를 합성부재로 사용할 경우, KBC2005 0709에 따라 ${415N/mm^{2}}$를 초과하지 못한다. 이는 일반 강구조의 경우의항복강도 ${440N/mm^{2}}$에 미치지 못한다. 따라서 본 연구는 순수강재 (원형강관, 각형강관) 단주 압축실험과 충전형 합성부재 단주, 장주 압축실험을 통하여 SM570TMC강을 충전형 합성기둥으로 사용할 때, 항복강도를 저감시키지 않고 일반 강구조의 공칭강도를 그대로 사용할 수 있는지를 정량적으로 평가하는데 그 목적이 있다.

• 대한토목학회논문집
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• 제31권1A호
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• pp.1-7
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• 2011

이 연구는 일정표면적 기둥의 좌굴하중에 관한 연구이다. 기둥단면의 변화깊이의 형상함수로는 선형 변단면을 채택하였다. 이러한 기둥의 좌굴형상을 지배하는 상미분방정식을 유도하기 위하여 축방향 압축력을 받는 기둥의 동적 평형방정식을 이용하였다. 수치해석 예에서는 회전-회전, 회전-고정, 고정-고정의 지점조건을 고려하였다. 수치해석의 결과로 각종 기둥변수들이 좌굴하중에 미치는 영향을 분석하였다. 특히, 일정표면적으로부터 최대 좌굴하중을 발생시킬 수 있는 기둥의 최강단면비와 그에 대응하는 최강좌굴하중을 산정하였다. 기둥 축에 횡방향 내부지점을 설치하여 좌굴하중을 증가시킬 수 있는 무변위 위치를 찾기 위하여 기둥의 좌굴형상을 산출하였다.

• Structural Engineering and Mechanics
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• 제31권4호
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• pp.371-382
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• 2009

The concrete plates are most widely used structural elements in the hulls of floating concrete structures such as concrete barges and pontoons, bridge decks, basement floors and liquid storage tanks. The study on the behavior of high-strength fiber reinforced concrete (HSFRC) plates was carried out to evaluate the performance of plates under in-plane and transverse loads. The plates were tested in simply supported along all the four edges and subjected to in-plane and traverse loads. In this experimental program, twenty four 150 mm diameter cylinders and twelve plate elements of size $600{\times}600{\times}30$ mm were prepared and tested. Water-to-cementitious materials ratios of 0.3 and 0.4 with 10% and 15% silica fume replacements were used in the concrete mixes. The fiber volume fractions, $V_f$ = 0%, 1% and 1.5% with an aspect ratio of 80 were used in this study. The HSFRC mixes had the concrete compressive strengths in the range of 52.5 to 70 MPa, flexural strengths ranging from 6.21 to 11.08 MPa and static modulus of elasticity ranging from 29.68 to 36.79 GPa. In this study, the behavior of HSFRC plate elements subjected to combined uniaxial in-plane and transverse loads was investigated.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 봄 학술발표회 논문집
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• pp.199-208
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• 1994

One of the main objectives of the study is to propose a practical but realistic limit state model considering combined effect of axial and bending load for reliability analysis and safety assessment of cable-stayed bridge under vehicle traffic loads. This paper is intended to propose a new approach for the evaluation of reserved load carrying capacity of cable-stayed bridge under vehicle traffic loads in terms of equivalent strength, which may be defined as a bridge strength corresponding to the reliability index of the bridge. This can be derived from an inverse process based on the concept of FOSM form of reliability index. AFOSM and IST methods are used for the reliability analysis of the proposed models. The proposed reliability model and methods are applied to the safety assessment of Jindo Bridge which is one of major two cable-stayed bridges in Korea.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.733-736
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• 1999

R/C columns, one of the main structural members of reinforced concrete structures, usually sustain the axial forces of combined dead loads and live loads. When subjected to lateral loads, however, they are repeatedly subjected to bending moment, shearing forces and brittle failure such as shear failure can occur. This failure mode is not desirable and extra reinforcement is usually needed to induce a ductile failure. The design equation which is used to evaluate the maximum shear strength of a R/C column is still unsatisfactory. The objective of this study was, therefore, to evaluate the hysteretic strengthening effect and the maximum shear strength of R/C columns strengthened using carbon fibers on the seismic performance of the R/C columns under anti-symmetrical by acting moment. According to this study, it may be suggested that the shear of the strengthened R/C column were adequate to induce ductile failures.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.287-292
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• 2001

Static behaviors of railway plate girder bridges designed by the L-22, a standard load type of the railway specification in Korea, are evaluated by widely eight load cases. The load cases are three real loads, which contain three locomotive types of Saemaul PMC, diesel, and Korea Train Express(KTX), and three design loads, L-22, L-18, and HL-25 loads, in railway specification. Plate girders for analysis have the length of spans of six types：6m, 9m, 12m, 22m, 24m, and 30m. For analysis SAP2000n ,a commercial FEM tool, is used. Dominant axial load types are taken from these results that are maximum deflections, reaction forces, and absolute maximum bending moment in girders.

• 한국소음진동공학회논문집
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• 제16권10호
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• pp.1074-1081
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• 2006

This paper deals with the dynamic stability analysis of clamped-hinged columns with constant volume. Numerical methods are developed for solving natural frequencies and buckling loads of such columns, subjected to an axial compressive load. The parabolic taper with the regular polygon cross-section is considered, whose material volume and column length are always held constant. Differential equations governing both free vibrations and buckled shapes of such columns are derived. The Runge-Kutta method is used to integrate the differential equations, and the Regula-Falsi method is used to determine natural frequencies and buckling loads, respectively. The numerical methods developed herein for computing natural frequencies and buckling loads are found to be efficient and robust. From the numerical results, dynamic stability regions, dynamic optimal shapes and configurations of strongest columns are reported in figures and tables.

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.729-745
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• 2012

This study presents dynamic analysis of laminated beams traversed by moving loads using a multilayered beam element based on the first-order shear deformation theory. The present element consists of N layers with different thickness and material property, and has (3N + 7) degrees of freedom corresponding three axial, four transversal, and 3N rotational displacements. Delamination and interfacial slip are not allowed. Comparisons with analytical and/or numerical results available in literature for some illustrative examples are made. Numerical results for natural frequencies, deflections and stresses of laminated beams are given to explain the effect of load speed, lamina layup, and boundary conditions.

• Steel and Composite Structures
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• 제33권1호
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• pp.133-142
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• 2019

In the present study, microstructure-dependent static stability analysis of inhomogeneous tapered micro-columns is performed. It is considered that the micro column is made of functionally graded materials and has a variable cross-section. The material and geometrical properties of micro column vary continuously throughout the axial direction. Euler-Bernoulli beam and modified couple stress theories are used to model the nonhomogeneous micro column with variable cross section. Rayleigh-Ritz solution method is implemented to obtain the critical buckling loads for various parameters. A detailed parametric study is performed to examine the influences of taper ratio, material gradation, length scale parameter, and boundary conditions. The validity of the present results is demonstrated by comparing them with some related results available in the literature. It can be emphasized that the size-dependency on the critical buckling loads is more prominent for bigger length scale parameter-to-thickness ratio and changes in the material gradation and taper ratio affect significantly the values of critical buckling loads.