• Steel and Composite Structures
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• 제50권1호
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• pp.1-13
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• 2024

The objective of this research is to study experimentally and numerically the behavior of steel beam columns with openings. Although the presence of openings in the beam columns is inevitable, finding ways to maintain strength is crucial. The studied parameters are opening shape, the ratio between opening height to specimen height, the percentage of opening location from support to beam column length, and web slenderness. Experimental tests are conducted including twelve specimens to study the effect of these parameters and record failure load, load deflection curve, and stress strain curve. Two failure modes are observed: local and flexural buckling. Interaction curves plotted from finite element model analysis are also used to expand the parametric study. Changing the location of the opening can decrease failure load by up to 7% and 60% in both normal and moment ratios respectively. Increasing the opening dimension can lead to a drop in the axial ratio by up to 29% and in the moment ratio by up to 74%. The weakest beam column behavior is noticed in specimens with rectangular openings which results from uneven and concentrated stresses around the opening. The main results of this research illustrate that the best location for opening is at 40% - 50% from beam column support. Also, it is advisable to use circular openings instead of rectangular openings in specimens having slender webs because moment ratios are raised by 85% accompanied by a rise in normal ratios by 9%.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.151-158
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• 2000

In this paper, It is presented that concrete-filled composite piers have large energy-absorption capacity and high strength and stiffness on account of mutual confinement between the steel plate and filled-in concrete. Concrete-filled composite columns were tested to failure under axial compression and cyclic lateral loading. Displacement ductility index obtained by using the load-displacement relation has been increased with the increment of filled-in concrete length, while it has been decreased according to the incrementation of width-thickness ratio, slenderness ratio and the number of loading cycles. Structural behavior and ductility index estimated for the seismic design showed that composite piers could be used as a very efficient earthquake-resistant structural member. The response modification factor could be re-evaluated for concrete-filled composite piers.

• Tribology and Lubricants
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• 제6권1호
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• pp.36-51
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• 1990

A parametric study of the thermal effects of a half-circumferential grooved journal bearings under aligned and misaligned conditions has been carried out by solving numerically the coupled Reynolds and energy equation system. Five different sets of boundary conditions for the energy equation have been used which include mixing between recirculating oil and inlet oil and a contraction ratio for the cavitation region. The effects of changes of the inlet oil temperature and pressure, the wall temperature and the L/D ratio have also been examined. For the range of parameters found in internal combustion engines, the mixing effectiveness at the groove and the resulting final mixture temperature have been found to be as important as the wall temperature and the heat transfer rate. The variability of the temperature, though, has been shown to smooth out the peaks of both pressure and friction during misaligned condition Distributions of friction and pressure in the oil are also examined which may be useful in attempts to reduce friction without reducing load. Results for an axial grooved bearing are also presentsed for comparision purpose.

• 한국지진공학회논문집
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• 제21권3호
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• pp.115-123
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• 2017

To investigate the cyclic characteristics of the retrofitted exterior joints of RC frame with haunch, 70% scaled 6 beam-column exterior joint subassemblies were designed according to design guideline according to 1988 and tested with cyclic loading up to 3.5% story drift ratio. During the experiments axial forces are applied to columns to simulate gravity load. Experimental results shows that the strength of retrofitted specimens was increased steadily until 2.5% story drift ratio and their strengths increased more than 1.7 times of the non-retrofitted in case that main bar was bent away from exterior joint. The joint strength and effective stiffness of the retrofitted specimen was increased and results in more deformation capacity compared to the non-retrofitted.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.891-896
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• 2001

The determination of compressive zone at the critical section of concrete walls under in-plane flexure is important in both assessing the ductility and designing the seismic retrofit. Recognizing this, the once-predominated code approach to determine the compressive zone was advanced by considering concrete rectangular stress block parameters varying with the extreme fiber strain in compression. It is shown that the major factors influencing the magnitude of compressive zone are axial load ratio, concrete strength, longitudinal steel ratio, yield strength and the level of strain at extreme compression fiber of wall sections. The present paper closes with the discussion for the research agenda requiring further study to investigate the behavior of reinforced concrete walls.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1203-1214
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• 2000

In this paper, a failure model for co-cured steel-composite tubular single lap joints has been proposed incorporating the nonlinear mechanical behavior of steel adherends and different failure mode s such as steel adherend failure and composite adherend failure. The characteristics of the co-cured steel-composite tubular single lap joint were investigated with respect to the test temperature, the stacking sequence of composite adherend, the thickness ratio of steel adherend to composite adherend, and the scarf ratio of steel adherend. Thus, the optimum design method for the co-cured steel-composite tubular single lap joint was suggested.

• 한국소음진동공학회논문집
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• 제21권4호
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• pp.384-391
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• 2011

This paper deals with free vibrations of the parabolic hollowed beam-columns with constant volume. The cross sections of beam-column taper are the hollowed regular polygons whose depths are varied with the parabolic functional fashion. Volumes of the objective beam-columns are always held constant regardless given geometrical conditions. Ordinary differential equation governing free vibrations of such beam-columns are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various beam-column parameters such as end constraints, side number, section ratio, thickness ratio and axial load are reported in tables and figures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.157-162
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• 2003

An experimental investigation was conducted to study the behavior of high-strength RC wide beam-column joints with slab subjected to reversed cyclic loads under constant axial load. Six half scale interior wide beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including three specimens without slab and three specimens with slab. The primary variables were compressive strength of concrete($f_ck$=285, 460kgf/$cm^2$), the ratio of the column-to-beam flexural capacity($M_r$=$\Sigma M_c / \Sigma M_b$ ; 0.77 -2.26), extended length of the column concrete($l_d$ ; 0, 12.5, 30cm), ratio of the column-to-beam width(b/H ; 1.54, 1.67). Test results are shown that (1) the behavior of specimen using high-strength concrete satisfied for required minimum ductile capacity according to increase the compressive strength, (2) the current design code and practice for interior joints(type 2) are apply to the wide beam-high strength concrete column.

• 콘크리트학회논문집
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• 제14권4호
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• pp.513-520
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• 2002

본 연구는 철근콘크리트 모멘트골조 기둥의 구조적인 성능을 평가하는 것이다. 이를 위하여 기존에 진행된 연구들의 실험결과를 모아 비교하였다. 본 연구에서 고려하는 실험변수는 소성힌지 부분에서 철근이음 유무, 종 방향 철근 비, 횡 방향 철근 비, 축력비이다. 또한, 본 연구에서는 시험체의 강도, 변위, 연성능력과 함께 소성힌지 길이를 비교하였다.

• Smart Structures and Systems
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• 제26권3호
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• pp.361-371
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• 2020

Exact solution for nonlinear behavior of clamped-clamped functionally graded (FG) buckled beams is presented. The effective material properties are considered to vary along the thickness direction according to exponential-law form. The in-plane inertia and damping are neglected, and hence the governing equations are reduced to a single nonlinear fourth-order partial-integral-differential equation. The von Kármán geometric nonlinearity has been considered in the formulation. Galerkin procedure is used to obtain a second order nonlinear ordinary equation with quadratic and cubic nonlinear terms. Based on the mode of the corresponding linear problem, which readily satisfy the boundary conditions, the frequencies for the nonlinear problem are obtained using the Jacobi elliptic functions. The effects of various parameters such as the Young's modulus ratio, the beam slenderness ratio, the vibration amplitude and the magnitude of axial load on the nonlinear behavior are examined.