• Journal of Korean Society of Steel Construction
• /
• v.15 no.4 s.65
• /
• pp.435-445
• /
• 2003

Tension member is one of the most important elements in tension structure. An economical and reliable measurement method of a member's tensile force has yet to be developed, however. Several conventional measurement methods have some disadvantages when used for long-term, on-site measurement. A new tension-force measurement device was proposed to resolve measuring problems. Its principle was to use the bending part of the device as an elastic spring. The lateral deformation of the bending part due to tensile force can be measured to monitor the tensile force. This device was inserted in the tension member like a turn-buckle. Lateral deformation may be measured in the field at any time for the purpose of maintaining structures. Finite element analysis was used to design the shape and parametric study. Six specimens were tested within the elastic range. The test result showed that the elastic behavior or the bending part was consistent with the analysis' results.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.5
• /
• pp.9-15
• /
• 2013

Roll-to-roll printing technology has lately become a subject of special interests in the field of printed electronics. Since this technology has the advantage that continuous and mass production is possible. And for high precision register control is required in multi-layer printing to produce the electronic devices, this is one of the most important technologies in roll-to-roll printing technology. Register error could be generated by various reasons like eccentricity of roll and thermal deformation due to temperature variation in drying section. In this study, the effect of tension variation on the register was analyzed. The results of these analyses show that it is essential to consider the tension disturbance which is generated by the change of temperature in drying section, and conventional register model has limitation to estimate the register error. In order to overcome the limitation of the register model, advanced register model based on the SI process was developed. Also, the performance of the developed model was verified experimentally.

• Interaction and multiscale mechanics
• /
• v.2 no.3
• /
• pp.223-233
• /
• 2009

This paper presents a new nonlocal stress variational principle approach for the transverse free vibration of an Euler-Bernoulli cantilever nanobeam with an initial axial tension at its free end. The effects of a nanoscale at molecular level unavailable in classical mechanics are investigated and discussed. A sixth-order partial differential governing equation for transverse free vibration is derived via variational principle with nonlocal elastic stress field theory. Analytical solutions for natural frequencies and transverse vibration modes are determined by applying a numerical analysis. Examples conclude that nonlocal stress effect tends to significantly increase stiffness and natural frequencies of a nanobeam. The relationship between natural frequency and nanoscale is also presented and its significance on stiffness enhancement with respect to the classical elasticity theory is discussed in detail. The effect of an initial axial tension, which also tends to enhance the nanobeam stiffness, is also concluded. The model and approach show potential extension to studies in carbon nanotube and the new result is useful for future comparison.

• Journal of Korean Society of Forest Science
• /
• v.95 no.4
• /
• pp.495-500
• /
• 2006

Stability of cable yarding with self-propelled carriage was discussed by theoretical tension calculation and field test. To verify usefulness of theoretical stability evaluation of cable yarding operation, skyline tension and stump anchoring force were measured and compared with theoretical calculation. As results, we know that measured skyline tension was similar to theoretical calculated tension. From these results, overall stability of cable logging operation could be evaluate. The stump anchoring force correlated closely with the stump diameters. The inclination angles that the stumps show the maximum anchoring force were ranged 5-10 degrees. It was conclude that the stumps have lost the function as an anchor when the inclinations was so large that they could be observed.

• Progress in Superconductivity and Cryogenics
• /
• v.24 no.1
• /
• pp.13-17
• /
• 2022

The mechanical properties of REBCO coated conductor (CC) tapes under uniaxial tension are mainly determined by the thick layer Components like the substrate and the stabilizer. Depending on the applications of the CC tapes, it is also needed to externally reinforce thin metallic foils to one side or both sides of the CC tapes. This study investigated the effect of additional stabilizer layers or lamination on the electrical resistivity and electromechanical properties in RCE-DR processed GdBCO CC tapes with different structures. The strain/stress tolerance of I_c in differently processed 12 mm-wide REBCO CC tapes under uniaxial tension at 77 K and self-field could be determined by the loading-unloading scheme. As a result, Sn-Cu stabilized CC tape showed a significant decrease in mechanical properties due to its soft but thick stabilizing layer. However, similar electromechanical properties have been observed on both Sn-Cu and Sn-stabilized CC tapes, the I_c degradation behavior was independent of whether the CC tape has an external reinforcement or different stabilizing layers.

• Structural Monitoring and Maintenance
• /
• v.10 no.3
• /
• pp.261-281
• /
• 2023

Magnetic flux sensors are commonly used in monitoring the cable force, but the application of the sensors in large diameter non-closed Galfan cables, as those adopted in Yueqing Gymnasium which is located in Yueqing City, Zhejiang Province, China and is the largest span hybrid space structure in the world, is seldom done in engineering. Based on the construction of Yueqing Gymnasium, this paper studies the cable tension monitoring using the magnetic flux method across two stages, namely, the pre-calibration stage before the cable leaves the rigging factory and the field tension formation stage of the cable system. In the pre-calibration stage in the cable factory, a series of 1:1 full-scale comparative tests were carried out to study the feasibility and relability of this kind of monitoring method, and the influence on the monitoring results of charging and discharging voltage, sensor location, cable diameter and fitting method were also studied. Some meaningful conclusions were obtained. On this basis, the real-time cable tension monitoring system of the structure based on the magnetic flux method is established. During the construction process, the monitoring results of the cables are in good agreement with the data of the on-site pressure gauge.The work of this paper will provide a useful reference for cable force monitoring in the construction process of long-span spatial structures.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.368-375
• /
• 2009

This paper describes field installation and load test results performed for three types of micropiles in the process of developing a new micropiling method. Field tests were performed for two conventional types(i.e., micropile reinforced with steel bar and gravity grouting, micropile reinforced with steel bar and steel casing and gravity grouting) and a proposed type(i.e., micropile reinforced with hollow steel pipe wrapped with geotextile-pack and pressurized grouting). The load test results subjected to axial compression and tension and lateral loading conditions are described in this paper. The micropiles were exposed in the air in order to verify the installation quality and curing condition of grouting material via ground excavation. Axial compression and tension test results indicate that the new micropile type provide at least 40% higher bearing capacity than that of conventional types. Based on the examination of exposed piles, it is induced that the proposed method, packed micropile, provides better interlocking between grouts and surrounding soils and increases higher frictional resistance comparing to conventional types.

• Structural Engineering and Mechanics
• /
• v.83 no.4
• /
• pp.435-449
• /
• 2022

Constitutive modeling that could reasonably predict and effectively evaluate the post-peak structural behavior while eliminating the mesh-dependency in numerical simulation remains to be developed for general engineering applications. Based on the previous work, a simple one-dimensional modeling procedure is proposed to predict and evaluate the post-peak response, as characterized by the evolution of localized strain field, of a steel member to monotonically uniaxial tension. The proposed model extends the classic one-dimensional softening with localization model as introduced by (Schreyer and Chen 1986) to account for the localization length, and bifurcation and rupture points. The new findings of this research are as follows. Two types of strain-softening functions (bilinear and nonlinear) are proposed for comparison. The new failure criterion corresponding to the constitutive modeling is formulated based on the engineering strain inside the localization zone at rupture. Furthermore, a new mathematical expression is developed, based on the strain rate inside and outside the localization zone, to describe the displacement field at which bifurcation occurs. The model solutions are compared with the experimental data on four low-carbon cylindrical steel bars of different lengths. For engineering applications, the model solutions are also compared to the experimental data of a cylindrical steel bar system (three steel bars arranged in series). It is shown that the bilinear and nonlinear softening models can predict the energy dissipation in the post-peak regime with an average difference of only 4%.

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.6
• /
• pp.707-716
• /
• 1997

Recent reports revealed that the $Na^+-Ca^{2+}$ exchangers and feet structures of sarcoplasmic reticulum(SR) are located in close vicinity in the specific compartment. Therefore, we investigated the possibility that the $Na^+-Ca^{2+}$ exchanger may decrease the tension development by transporting the $Ca^{2+}$ out of the cell right after it released from SR, on the basis of this anatomical proximity. We exammined the negative force-frequency relationship of the developed tension in the electrically field stimulated left atria of postnatal developing rat(1, 3 day, 1 week and 4 week old after birth). Cyclopiazonic $acid(3{\times}10^{-5}\;M)$ treatment decreased the developed tension further according to postnatal age. $Monensin(3{\times}10^{-6}\;M)$ treatment did not increase the maximal tension in 4 week-old rat, preserving negative staircase, while the negative staircase in the younger rat were flattened. $Ca^{2+}$ depletion in the buffer elicited more suppression of the maximal tension according to the frequency in all groups except the 4 week-old group. The % decrease of the maximal developed tension of 4 week-old group at 1 Hz to that of 0.1 Hz after $Na^+$ and $Ca^{2+}$ depletion was only a half of those of the yonger groups. Taken together, it is concluded that the $Na^+-Ca^{2+}$ exchange transports more $Ca^{2+}$ released from SR out of the cell in proportion to the frequency, and this is responsible for the negative staircase effect of the rat heart.

• Journal of Korean Society of Steel Construction
• /
• v.11 no.3 s.40
• /
• pp.291-299
• /
• 1999

In this paper, an experimental study have been many studies on the propriety of block shear design code. according to limited state design criteria of steel structures recently established in Korea, by an experiment on the joint of H-Beam Flange tension members. The objects of this study were to compare with the results of other studies on block shear rupture mode and ultimate capacity, and to evaluate the propriety of the design criteria. The result is that the joint happened, two types, tension yield-shear ruptures and shear yield-tension ruptures, and the experimental rupture load was 23% higher than the capacity entered in the criteria design code In this criteria, it was found that ultimate strength of block shear of H-Beam Flange was lowly estimated. Therefore, we emphasize the need of estimates on the block shear rupture by carrying out many studies in this field.