• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.563-580
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• 2010

Composite beams using bolts to attach steel plates to the side faces of existing reinforced concrete (RC) coupling beams can enhance both their strength and deformability. The behavior of those composite beams differs substantially from the behavior of typical composite beams made up of steel beams and concrete slabs. The former are subjected to longitudinal, vertical and rotational slips, while the latter only involve longitudinal slip. In this study, a mixed analysis method was adopted to develop the fundamental equations for accurate prediction of the load-carrying capacity of steel plate strengthened RC coupling beams. Then, a rigid plastic analysis technique was used to cope with the full composite effect of the bolt group connections. Two theoretical models for the determination of the strength of medium-length plate strengthened coupling beams based on mixed analysis and rigid plastic methods are presented. The strength of the strengthened coupling beams is derived. The vertical and longitudinal slips of the steel plates and the shear strength of the anchor-bolt connection group is considered. The theoretical models are validated by the available experimental results presented in a companion paper. The strength of the specimens predicted from the mixed analysis model is found to be in good agreement with that from the experimental results.

• Biomolecules & Therapeutics
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• v.27 no.4
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• pp.342-348
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• 2019

Ossification of the posterior longitudinal ligament (OPLL) can be defined as an ectopic ossification in the tissues of spinal ligament showing a hyperostotic condition. OPLL is developed mostly in the cervical spine and clinical presentations of OPLL are majorly myelopathy and/or radiculopathy, with serious neurological pathology resulting in paralysis of extremities and disturbances of motility lowering the quality of life. OPLL is known to be an idiopathic and multifactorial disease, which genetic factors and non-genetic factors including diet, obesity, physical strain on the posterior longitudinal ligament, age, and diabetes mellitus, are involved into the pathogenesis. Up to now, surgical management by decompressing the spinal cord is regarded as standard treatment for OPLL, although there might be the risk of development of reprogression of ossification. The molecular pathogenesis and efficient therapeutic strategy, especially pharmacotherapy and/or preventive intervention, of OPLL has not been clearly elucidated and suggested. Therefore, in this review, we tried to give an overview to the present research results on OPLL, in order to shed light on the potential pharmacotherapy based on molecular pathophysiologic aspect of OPLL, especially on the genetic/genomic factors involved into the etiology of OPLL.

• Steel and Composite Structures
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• v.45 no.5
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• pp.665-682
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• 2022

In the current study, punching behavior of Reinforced concrete (RC) isolated footings was experimentally and numerically investigated. The experimental program consisted of four half-scale RC isolated footing specimens. The test matrix was proposed to show effect of footing area, reinforcement mesh ratio, adding internal longitudinal reinforcement bars and stirrups on the punching response of RC isolated footings. Footings area varied from 1200×1200 mm2 to 1500×1500 mm2 while the mesh reinforcement ratio was in the range from 0.36 to 0.45%. On the other hand, a 3D non-linear finite element model was constructed using ABAQUS/standard program and verified against the experimental program. The numerical results agreed well with the experimental records. The validated numerical model was used to study effect of concrete compressive strength; longitudinal reinforcement bars ratio and stirrups concentration along one or two directions on the ultimate load, deflection, stiffness and failure patterns of RC isolated footings. Results concluded that adding longitudinal reinforcement bars did not significantly affect the punching response of RC isolated footings even high steel ratios were used. On the contrary, as the stirrups ratio increased, the ultimate load of RC isolated footings increased. Footing with stirrups ratio of 1.5% had ultimate load equal to 1331 kN, 19.6% higher than the bare footing. Moreover, adding stirrups along two directions with lower ratio (0.5 and 0.7%) significantly enhanced the ultimate load of RC isolated footings compared to their counterparts with higher stirrups ratio (1.0 and 1.5%).

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.529-532
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• 1999

With increasing use of high-strength concrete tied columns in structural engineering, it becomes necessary to examine the applicability of related sections of the current design codes. This experimental study was conducted to investigate the behavior of eccentrically loaded high-strength concrete columns. Column specimens with concrete strength 234, 437, 703kgf/㎠ were tested under monotonically increasing eccentric compression. The test parameters included the longitudinal reinforcement ratio, eccentric distance and concrete compressive strength. The analytical results obtained from the stress-strain relationship and the ACI's equivalent rectangular stress block are compared with experimental test results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.3
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• pp.183-192
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• 1981

The present study gives an apprximate equation of circular cylindrical shell on the basis of Flugges's exact theory. The longitudinal bending moment .MU.$\_$x/ and circumferential strain .epsilon.$\_$.theta. are assumed to be small to be small and have been neglected. The governing equation of the cylindrical shell, which is generaly presented as 8th order partial differential equation, is reduced into a 4th order partial differential equation for axial coordinate. To verify the validity and accuracy of this approximate theory, the cantilever cylindrical shell subjected to a concentrated load is analyzed. The maximum errors of longitudinal stress and deflection are about 10 percent compared with the analysis by flugge's theory and are about 15 percent with experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3152-3159
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• 1996

Previous works about the cylindrical shape elastic body which is under longitudinal temperature distribution mostly show the results of free expansion, therefore exact thermo-elastic analysis is needed. The object of this work is to analyze the thermo-elastic problem of the hollow cylinder when the cylinder is under longitudinal temperature distribution. In this paper, the analytical solution is found by using Galerkin vector, and it is compared by the results of FEM. For displacements of cylinder, analytical values are almost same as the results of FEM, but free expansion is not fit for analytical solution and the results of FEM. stresses from analytical solution and the results of FEM show good agreement also. but the results are different near the end boundary, since St. Venant principle is applied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.3 s.258
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• pp.338-343
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• 2007

Thermal deformation of cast iron exhaust manifold for turbo diesel engine is investigated by finite element analysis (FEA). The FE model included the temperature dependent material properties as well as the interactions between exhaust manifold, cylinder head and fasteners. It also considers the sliding behavior of the flanges of exhaust manifold on cylinder head when either expansion or contraction of the exhaust manifold exceeds the fastener pretension. The result of analysis revealed that remarkable thermal deformation along the longitudinal direction. Compressive plastic deformation at high temperature remained tensile stress in manifold and resulted in longitudinal contraction at ambient temperature. The amount of contraction at each fastener position was predicted and compared with experimental results. Analysis results revealed that the model predicted deformation qualitatively, but more elaborated cyclic hardening behavior would be necessary to predict the deformation quantitatively.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.47-52
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• 2008

The force transducer in the acceleration plant due to dynamic fracture is calibrated by dynamically using the stress pulses from a longitudinal bar. The bar is supported by two strings attached to the ceiling. The bar velocities before and after impact are measured and a full bridge at bar and transducer is formed by the four strain gauges. A transient recorder is used to store the stress pulse signals of force transducer and bar. For the first test series, three point bend test specimens can be chosen by means of test rig design and the inspection as sample experiment in this presented paper is sufficient for proving with the numerical simulation of the specimen model.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.224-227
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• 2003

The longitudinal thermosonic bonding method is investigated in this work for its application to the soldering process for electronic packaging. The effect of the ultrasonic is analyzed through lumped modeling, and the material properties of a viscoelastic model are measured experimentally. The thermosonic bonding method is verified by inserting the Cu pin and Au bump into solder block. As the solder thickness decreases, temperature of the solder is calculated to increase rapidly because of larger strain. Localized heating due to ultrasonic vibration is observed to melt the solder near the pin, which is adequate to the high density electronic package and Pb-free solder having high melting temperature.

• Structural Engineering and Mechanics
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• v.9 no.6
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• pp.589-600
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• 2000

This paper attempts to provide a theoretical basis for the design of high-strength concrete columns in terms of the spacing of lateral reinforcement. In order to achieve this, important concepts had to be addressed such as the choice of a measure of ductile behaviour and a realistic high-strength concrete stress-strain model, as well as limiting factors such as longitudinal steel buckling and lateral steel fracture. A design method incorporating above factors are suggested in the paper. It is shown that both buckling of longitudinal steel and hoop fracture will not demand a reduction in spacing of lateral ties with increase in compressive strength of concrete.