• Journal of computational fluids engineering
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• v.16 no.1
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• pp.7-13
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• 2011

The fluid-structure interaction of a towed body is simulated using a developed code, which is based on the flux-difference splitting scheme on the hybrid Cartesian/immersed boundary method. To improve the stability in the coupling between the fluid and structure domains, a scheme is used, in which the effects of structure deformation are treated implicitly. The developed code is validated for the fluid-structure interaction problem through comparisons with other results on the vortex-induced vibration of elastically mounted cylinders. To simulate behavior of a towed body, an asymmetric tension modelling for a towing cable is suggested. In the suggested model, the tension is proportional to the elongation of the cable, but the cable has no effect on the body motion whenever the distance between the endpoints of the cable is smaller than the original length of the cable. The fluid-structure interactions of a towed body are simulated on the basis of different parameters of the towing cables. It is observed that the suggested tension model predicts the snapping for a shorter towing cable, which is in accordance with the reported results.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.2
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• pp.61-68
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• 2014

Constructing structures is the basic process requiring establishment of grounds. However, cracks due to sinking and distorting ground influence directly on the safety of structural health. Vibrating wire sensor measures the crack of structure by detecting the differences of wire tensions in analogue manner. In the previous production process, the tension is adjusted manually measuring the frequency of vibrating wire. Therefore, the accuracy of a sensor was depends on the skill level of labor. In this study, the automatic tension control and fixing devise is developed to enhance both accuracy and productivity. To evaluate the performance of the vibrating wire sensor, the nonlinearity of sensor is measured. The automatic tension control and fixing devise enhances the nonlinearity of the sensor from 0.398 to 0.056%. Therefore, the accuracy of the newly proposed method is successful.

• Computers and Concrete
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• v.17 no.1
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• pp.29-51
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• 2016

Tension-stiffening is the contribution of concrete between the cracks to carry tensile stresses after cracking in Reinforced Concrete (RC) members. In this paper, a tension-stiffening model has been proposed for computationally efficient nonlinear analysis of RC flexural members subjected to service load. The proposed model has been embedded in a typical cracked span length beam element. The element is visualized to consist of at the most five zones (cracked or uncracked). Closed form expressions for flexibility and stiffness coefficients and end displacements have been obtained for the cracked span length beam element. Further, for use in everyday design, a hybrid analytical-numerical procedure has been developed for nonlinear analysis of RC flexural members using the proposed tension-stiffening model. The procedure yields deflections as well as redistributed bending moments. The proposed model (and developed procedure) has been validated by the comparison with experimental results reported elsewhere and also by comparison with the Finite Element Method (FEM) results. The procedure would lead to drastic reduction in computational time in case of large RC structures.

• Structural Engineering and Mechanics
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• v.68 no.3
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• pp.345-358
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• 2018

Heterogeneous structure and, particularly, low resistance to tension stresses leads to different mechanical properties of the concrete in different loading situations. To solve this problem, the tension zone of concrete elements is reinforced. Development of the cracks, however, becomes even more complicated in the presence of bar reinforcement. Direct tension test is the common layout for analyzing mechanical properties of reinforced concrete. This study investigates scatter of the test results related with arrangement of bar reinforcement. It employs results of six elements with square $60{\times}60mm$ cross-section reinforced with one or four 5 mm bars. Differently to the common research practice (limited to the average deformation response), this study presents recordings of numerous strain gauges, which allows to monitor/assess evolution of the deformations during the test. A simple procedure for variation assessment of elasticity modulus of the concrete is proposed. The variation analysis reveals different deformation behavior of the concrete in the prisms with different distribution of the reinforcement bars. Application of finite element approach to carefully collected experimental data has revealed the effects, which were neglected during the test results interpretation stage.

• Journal of the Korean Society of Safety
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• v.24 no.5
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• pp.1-5
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• 2009

NiTiCu alloys can produce a large force per unit volume and operate with a simple mechanism. For this reasons, it has been widely studied for application as a micro actuator. So in this study, one-way and two way shape memory effects of Ti-42.5at%Ni-2.0at%Cu alloys are studied. In the case of one-way shape memory effects, shape memory recoverable stress and strain of this alloys were measured by means of tension and compression tests under constant temperature. The strains by tension and compression stress were perfectly recovered by heating at any testing conditions also shape memory recoverable stress increased to 116 MPa in tension tests and to 260 MPa in compression tests. In the case of two-way shape memory effects, transformation temperatures from thermal cycling under constant uniaxial applied tension and compression loads linearly increased by increasing external loads and their maximum recoverable strain is 3.8% at 100MPa tensile condition and 2.2% at 125 MPa compression condition.

• Journal of ILASS-Korea
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• v.6 no.4
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• pp.22-30
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• 2001

The objective of this study is to develop the new equations for the calculation of higher heating values(HHVs) of reformed diesel fuels by ultrasonic treatment. Therefore, higher heating values of reformed diesel fuels by ultrasonic treatment are determined experimentally and calculated from their viscosity and surface tension measurements. The HHVs of the fuels are supposed to be a function of viscosity(Pa s) and surface tension(N/cm). The equations developed for the samples represent the correlation obtained by means of regression analysis. The HHVs calculated by developing new equations using viscosities showes the differences from the measured values ranging from -0.66 to 1.19 % and the correlation coefficient was -0.9411. The HHVs calculated by developing new equations using surface tensions showed the differences from the measured values ranging from -0.70 to 1.51 % and the correlation coefficient was 0.9999. The viscosity and the surface tension are characteristic properties of ultrasonic reformed diesel fuels for developing new formulae.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.171-178
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• 2008

This paper is concerned with the development of a measurement system using field measuring device which will give the membrane stress of the membrane structures. Up to this point, several techniques on measurement of membrane stresses has been proposed and some have been used in the fields, but accuracy of the measured stresses to be far from reliable one. Such situation has not been changed until recent days, we do not have the measurement device on which we can depend. On top of that, due to the different properties in cross directions for material of the membrane, the stress in the warp direction is different from that in the fill one. A new method is proposed to measured membrane stresses in two different direction separately, where instead of membrane stresses directly, an external force perpendicular to the membrane to be applied. A portable device can measure the applied force and the displacement. A special testing bed to be fabricated to accommodate $50cm{\times}50$ manbrane specimen which can apply 5 ton load in two orthogonal direction. A special device using push-pull gage was developed. To measure the membrane stresses in warp and fill direction separately, a different length of the tips are used. The measuring device which can called tension meter, can be calibrated on the testing bed, and optimized the length and shape of tip.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.788-795
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• 2005

In this study, the progressive failure and creep of the traditional ground anchor structure were decreased and a new ground anchor that can attain the required pull-out resistance even in soft sandy soils with low confining pressure was developed. Ground anchors are classified depending on the kind of stress the grout is subjected. If the grout material is subjected to tension then it is classified as tension anchor while when the grout material is subjected to compression it is classified as compression anchor. The ground anchor that possesses both the tension and compression mechanism mentioned above is known as composition anchor. It is the objective of this study to develope this type of composition anchor. The structure of the newly developed ground anchor was presented. Pull-out test in different types of soil and the behaviour during Pull-out test was also presented.

• Journal of Korean Association for Spatial Structures
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• v.9 no.2
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• pp.91-97
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• 2009

This study presents geometric nonlinear and material analysis of under-tension structure using Total Lagrangian and Updated Lagrangian method. In the regard, the under-tension system enables the load of upper part to carry to the end of beam by pre-tensional force in cable. The under-tension system on lower part of the structure is applied in order to reduce the deflection and size of member. This study is performed with conforming of the effect by pretension value in the cable and applying loading. Dead and Live loads are supposed to apply nodal on the top member. The member force and deflection of the structure are with MIDAS and ADINA.

• Herbal Formula Science
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• v.21 no.1
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• pp.206-212
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• 2013

Objectives : The purpose of this study is to report the clinical effects of Dangkisoo-san and acupuncture on a patient with Tension Type headache. Methods : We have given Dangkisoo-san and acupuncture treatment to a patient with Tension Type headache for 8days, and checked changes of symptoms. Main symptoms were numbness and pains in a head and a neck. Results : After treatment, the numbness and pains in a head and a neck were improved considerably. Conclusions : This study shows that Dangkisoo-san and acupuncture are significantly effective in treatment of Tension Type headache.