• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.563-570
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• 2006

Distributed control architecture is based on sharing control and data between multiple nodes on a network Communication and task sharing can be distributed between multiple control computers. Although many communication protocols exist, such as TCP/IP and UDP, they do not have the determinism that realtime control demands. Fiber-optic reflective shared memory creates the opportunity for realtime distributed control. This architecture allows control and computational tasks to be divided between multiple systems and operate in a deterministic realtime environment. One such shared memory architecture is based on Curtiss-Wright ScramNET family of fiber-optic reflective memory. MTS has built seismic and structural control software and hardware capable of utilizing ScramNET shared memory, opening up infinite possibilities in research and new capabilities in Hybrid and Model-In-The-Loop control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.814-821
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• 2015

The purpose of this study is to estimate crack reduction properties of covering concrete with fibers in basement. Air contents, slump, compressive strength, tensile strength and plastic shrinkage has been tested to conduct the optimum addition ratio and type of fiber. The results is a following. For the properties of air contents, all of the specimens added fibers shown the higher than plain concrete. For the flowability, slump decreased about 40-80% when all of the specimens added fibers. For the strength properties, the specimens added nylon fiber shown higher compressive and tensile strength about 5-15% comparing with other concrete. For the plastic shrinkage, cracking decreased when the fiber added comparing with plain concrete. Especially, when nylon fiber added in the concrete, the plastic shrinkage did not occurred. For the overall consideration, when the addition ratio of nylon fiber is 0.6%, the press concrete is identified as showed optimum properties.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.255-261
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• 2019

The purpose of this study is to investigate effects of types of synthetic fibers on mechanical properties of alkali-activated slag composite. Materials and mixture proportion for matrix are determined, and the compressive strength, tensile performance, and cracking patterns of three composites reinforced by polypropylene, polyvinyl-alcohol, and polyethylene fibers. From the test results, it was observed that polyvinyl-alcohol fiber-reinforced composite and polyethylene fiber-reinforced composite had similar tensile performance. On the other hand, polypropylene fiber-reinforced composite showed low tensile performance. And it was exhibited that other factors except tensile strength and aspect ratio of fiber influence significantly tensile behavior of composite.

• Steel and Composite Structures
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• v.10 no.2
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• pp.187-205
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• 2010

The existing CFT columns present the deterioration in confining effect after the yield of steel tube, local buckling and the deterioration in load capacity. If lateral load such as earthquake load is applied to CFT columns, strong shearing force and moment are generated at the lower part of the columns and local buckling appears at the column. In this study, axial compression test and beam-column test were conducted for existing CFT square column specimens and those reinforced with carbon fiber sheets (CFS). The variables for axial compression test were width-thickness ratio and the number of CFS layers and those for beamcolumn test were concrete strength and the number of CFS layers. The results of the compression test showed that local buckling was delayed and maximum load capacity improved slightly as the number of layers increased. The specimens' ductility capacity improved due to the additional confinement by carbon fiber sheets which delayed local buckling. In the beam-column test, maximum load capacity improved slightly as the number of CFS layers increased. However, ductility capacity improved greatly as the increased number of CFS layers delayed the local buckling at the lower part of the columns. It was observed that the CFT structure reinforced with carbon fiber sheets controlled the local buckling at columns and thus improved seismic performance. Consequently, it was deduced that the confinement of CFT columns by carbon fiber sheets suggested in this study would be widely used for reinforcing CFT columns.

• Food Science of Animal Resources
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• v.42 no.5
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• pp.874-888
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• 2022

This study aimed to compare the similarities, physicochemical properties, and muscle fiber characteristics of porcine skeletal muscles. Fourteen types of muscles were collected from nine pig carcasses at 24 h post-mortem and classified by muscle architecture into two main groups, namely parallel and pennate. The muscles were further differentiated into three subtypes per group. These included fan-shaped, fusiform, and strap for the parallel group, and unipennate, bipennate, and multipennate for the pennate group. Parallel-fibered muscles, which were composed of larger I, IIA, IIX, and IIXB fibers and a lower density of IIA fibers, showed higher redness and yellowness values than pennate-fibered muscles (p<0.05). However, the relative fiber area was not significantly different between the parallel and pennate groups (p>0.05). In the subtypes of parallel architecture, the strap group showed lower moisture content and higher redness values than the other subtypes and had considerably higher amounts of oxidative fibers (I and IIA; 72.3%) than the fan-shaped and fusiform groups (p<0.05). In the pennate group, unipennate showed comparatively lower moisture content and higher lightness than other pennate subtypes and was composed of smaller I, IIA, and IIX fibers than the bipennate and multipennate groups (p<0.05). Finally, a different trend of muscle clustering by hierarchical cluster analysis was found between physicochemical properties and muscle fiber characteristics. These results suggest that the physicochemical properties and muscle fiber characteristics of porcine skeletal muscles are not significantly dependent on morphological properties but are rather related to the intrinsic properties of the individual muscles.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.759-766
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• 2004

The addition of steel fiber with concrete significantly improves the engineering properties of structural members, notably shear strength. The purpose of this study is to determine the steel fiber shape, aspect ratio and volume fraction ratio in a point of practical usage as structural members. Steel fiber factor and volume fraction are also considered to verify the strengthening effect in member level. From the reviewing of previous researches and analyzing of consecutive material test results, the optimum shape and length of steel fiber, which can have a good strengthening effects were defined as a hooked end type and larger than 1.5 times of maximum gravel size. Analyzing the test results of strength and deformation capacity, aspect ratio 75 and volume fraction $1.5\%$ can be having a maximum strengthening effect of steel fiber. Also steel fiber factor, tensile splitting strength, and flexural strength are found as key parameter in shear strengthening effect in member level.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.143-152
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• 2015

In the present study, the fiber and matrix failure of composite laminates under arbitrary biaxial stresses were evaluated based on separate mode criteria such as Hasnin and Puck theories. There is a limitation to predict the fiber-dominant and/or matrix-dominant failures under arbitrary stress states using limit criteria (maximum stress and maximum strain theories) and interactive criteria (Tsai-Hill and Tsai-Wu theories). There is little literature for failure analysis of ships and offshore composite structures considering advanced failure theories such as Hashin and Puck theories. Furthermore, there is not enough practical commercial finite element analysis (FEA) code which is basically adopted the separate mode criteria. Hence, in the present study, the user-defined subroutine of commercial FEA code ABAQUS for evaluation of fiber and matrix failures of composite structures was developed based on Hashin and Puck failure criteria. And then, the proposed subroutine was validated by comparing with a series of experimental results of carbon- and glass-implemented composite laminates to guarantee the reliability and usefulness of the developed method.

• Journal of the Korea Concrete Institute
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• v.27 no.3
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• pp.229-236
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• 2015

This paper describes the effect of aggregate size on compressive behavior of high-strength steel fiber reinforced concrete. The Specified compression strength is 60 MPa and the range of fiber volume fraction is 0~2%. The main variable is the aggregate size, which was used for the aggregate size of 8 and 20 mm. So, ten concrete mixtures were prepared and tested to evaluate the fresh and hardened properties of SFRC at curing ages (7, 14, 28, 56 and 91 days), respectively. Items estimated in this study are the fresh properties (air contents, slump), hardened properties (compressive strength, modulus of elasticity, post-peak response and compressive toughness). As a result, the aggregate size has little effect on the compressive strength and modulus of elasticity. On the other hand, the ductile behavior was shown after post peak and the compressive toughness was increasing as decreasing the aggregate size. These effects are clearly represented in the fiber volume fraction 2%, which are the point appeared fiber ball. It is considered that the decreasing the aggregate size has effect on the fiber dispersibility.

• Coupled systems mechanics
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• v.10 no.6
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• pp.545-560
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• 2021

An in situ experiment imaged via X-ray computed tomography was performed on a continuous glass fiber mat reinforced epoxy resin composite. The investigated dogbone specimen was subjected to uniaxial cyclic tension. The reconstructed scans (i.e., gray level volumes) were registered via Digital Volume Correlation. The calculated maximum principal strain fields and correlation residual maps exhibited strain localization areas within the material bulk, thus indicating damage inception and growth toward the specimen surface. Strained bands and areas of elevated correlation residuals were mainly concentrated in the narrowest gauge section of the investigated specimen, as well as on the specimen ligament edges. Gray level residuals were laid over the corresponding mesostructure to highlight and characterize damage development within the material bulk.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.293-298
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• 2006

The reinforced concrete(RC) structures strengthened with fiber reinforced plastic(FRP) has been accepted by the construction engineering community for rehabilitation. FRP composites can present many advantages like a corrosion resistance, strength-weight ratio, relatively short application time, and cost effectiveness. The beams under design load, however, are cracked and result in degrading the strength. It is difficult to recognize cracks and deflections on the surface of the concrete members retrofitted with FRP through the life cycle. For these reasons, if they result in the effects, which were below the expected strength, we must monitor the state of concrete structures all the time in order to take an appropriate measure. Fiber Bragg Grating(FBG) sensor excel as monitoring of investigating the stress state of the retrofitted beams with FRP. The main objective of this study is to measure strain by experiment and analyze the behavior of RC beams retrofitted with FRP using FBG sensor. The kinds of FRP which were used in research are carbon, glass and improved hybrid FRP(IFRP) that has capacity than any other FRP. Other variables are the length of FRP, the number of sheet.