• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.869-871
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• 1998

The extensive use of composite insulators for transmission lines can ultimately be justified only on long-term qualification tests. The actual load working on the insulator in the field is not static load but cyclic load. So in this paper, we discussed an examination of aging degradation by mechanical performance of composite insulators under static tension load and cyclic tension load. and also described useful approaches for analyzing their long term performance so as to develop reliable composite insulators. The static and cyclic tension load-time test data were examined by Weibull distribution for their capability of presuming long term performance. It was found that cyclic tension loads were more severe than static tension loads. The results also indicate that it may be relevant for an user to select composite insulators on basis of their performance under cyclic tension loads than static tension loads.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.737-742
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• 1998

The tension stiffening effect is defined as the increase in stiffness in reinforced concrete member due to the stiffness provided by concrete between cracks. If this is disregarded in analysis of reinforced concrete members, especially at the level of service loads, member stiffnesses may be underestimated considerably. This paper presents on the failure behavior and tension stiffening of RC tension test with main variables such as concrete strength, rebar diameter and strength. The tension stiffening was analyzed from the load-displacement relationship by ACI code and the proposed by Collins & Mitchell. In summary, the effect of tension stiffening decrease rapidly as the rebar diameter increase, rebar strength increase, and concrete strength increase. The effect of tension stiffening on RC member is the biggest near the behavior of concrete cracking and decrease as the load close to the breaking point. Thus, the tension stiffening should be considered for the precise analysis near the load of concrete cracking.

• Transactions of Materials Processing
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• v.10 no.1
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• pp.53-58
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• 2001

Set-up reference values, used in determining the optimum downcoiling tension, we experimentally verified in this study. During the actual downcoiling, the strip suffers both tension and bending force through the rotation of mandrel. Therefore, simulative test which can measure both tension and bending resistance of strip was performed to estimate set-up reference value for strip tension during downcoiling operations. The values obtained from the simulative test were correlated with the yield stress which has conventionally been used as reference values for downcoiling tension. The correlative analysis showed that the yield stress of strip can be a good reference value for downcoiling tension. Furthermore, the bending load also shows strong correlation with simulated values due to the close relationship between yield stress and bending load.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1126-1130
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• 1999

This paper persents an algorithm compensating for the change of tension acting on a belt which is used as a force transfer media of the induction motor that drives a washing machine. The induction motor adopted in a washing machine is operated not only for the power-transmission device, but also for the detection of clothes load. The load of clothes is determined by the duration of inertial rotation which is occurred by the induction motor during a specific time. The tension of belt also affects the determination of clothes load as another load and this change of the tension is a significant disturbance for accurate determination. This paper mentions the algorithm compensating for the amount of change in tension and the application of the algotithm proved to be effectively increasing the washing performance and reducing the noise and the vibration.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.503-509
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• 1999

This paper proposes a new speed and tension control algorithm for multi-span continuous strip processing line. In this algorithm the speed reference of each roll is adjusted to make the output force follow the load balance reference using an outer loop controller in cascade. Using the information of the output force of the adjacent roll, it is shown that the strip tension between two rolls can be controlled as the desired value without tension sensor. An experimental set-up which consists of 4 driven and 3 measuring rolls is designed and built for the multi-span speed and tension control. The experimental result reveals conspicuous improvement of tension control performance by the proposed algorithm comparing to the conventional tension feedback controller.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.42-48
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• 2012

Peel-tension fatigue experiments were conducted for investigating on fatigue strength of mechanical press joints of SPCC steel sheet used in the field of the automobile industry. In addition, finite element method analysis on the peel-tension specimen was conducted using HyperMesh and ABAQUS softwares. The cold rolled mild steel was used to join the T-shaped peel-tension specimen with a button diameter of 5.4 mm and a punch diameter of 8.3 mm. The fatigue limit load amplitude was found to be 112.4 N at the number of cycles 106, indicating that the ratio of fatigue limit load to static peel-tension strength was about 8%. This value suggests that the mechanical press joint is highly vulnerable to peel-tension load rather than to tensile-shear load, considering that the ratio of fatigue limit load to static tensile-shear strength was about 43%. Fatigue failure mode was found to be interface-failure mode.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.4
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• pp.120-129
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• 1998

The tension stiffening in reinforced concrete member means increase of stiffness caused by the effective tensile stress between cracks and the tension softening behavior of concrete. This paper presents on the tensile behavior and tension stiffening of RC tension members. Direct tension tests were performed with a main experimental variables such as concrete strength, rebar diameter and strength. The tension stiffening was analyzed from the load-displacement relationship and was compared with ACI code, CEB model and the proposed by Collins ＆ Mitchell. The results are as follows : The tension behaviors of RC members were quite different from those of bare bar and were characterized by loading and concrete cracking steps. The effect of tension stiffening decreased rapidly as the rebar diameter and strength increased, and the concrete strength increased. The proposed by Collins ＆ Mitchell described well the experimental results, regardless of rebar types and concrete. But, ACI code and CEB model described a little differently, depending on the types. The effect of tension stiffening in RC member was the biggest near at concrete cracking step and decreased gradually to the bare bar's behavior as loading closed to the breaking point. Thus, tension stiffening in RC members should be taken into account when the load-deflection characteristics of a member are required or a precise analysis near the load of concrete clacking is needed.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.301-308
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• 2015

In this paper, we propose an LTBC (Low Tension and Load Balance Control) scheme to improve a coiling shape control by reduction the tension fluctuation by the torque disturbance in the down coiler process of hot strip mills. The proposed controller is a combination of an LTC to control the overload at load-on in the mandrel and an LBC to regulate the load balance of the upper and bottom pinch roll. A tension calculation model is suggested with the concept of the tension deviation. The effectiveness of the proposed control scheme is verified from simulation under a disturbance of the pinch roll torque. Using a field test, we show that the performance of the shape and tension control is improved by the LTBC control.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.297-302
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• 2015

To prevent cargo accidents by repeated loads, a continuous monitoring for securing rope or additional safety measures are needed, but most of prevention measures have been conducted only by operator's own experience not a quantitative assessment. Hence, the Load-Displacement curve and approximation formula of securing rope were drawn in this research for a quantitative assessment and simplified measurement on a tension of securing rope using a tensiometer. Moreover, a com parison was conducted between m easuring tension and calculated tension on securing rope with portable tensiometer, 'Load-Displacement' approximation formula. The calculated tension of securing rope is obtained 153.3kfg using the formula and that result has not much difference with initial tension 150.0kgf. Lastly, an analysis of the characteristics of various ropes was suggested to enhance the reliability about quantitative assessment of securing rope's tension through further research.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3415-3423
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• 1996

The compact tension specimen geometry has been widely used for measuring fatigue crack growth rates at elevated temperature when the fatigue load is under tension/tension condition. However, most of the elevated temperature components which have significant crack growth life experience fatigue load under tension/compression conditions. Thus test techniques are required since the compact tension specimen cannot be used for tension/compression loading. In this paper, a simplified test procedure for measureing fatigue crack growth rates is proposed, which employs a round bar specimen with a small surface crack. Fatigue crack growth rates under tension/ tension loading conditions at elevated temperature were measured according to the proposed procedure and compared with those previously measured by C/(T) specimens. Since both the measured crack growth rates were comparable, the fatigue crack growth rates under tension/ compression load can be reliably measured by the proposed procedure. For monitoring crack depth. DC electric potential method is employed and an optimal probe location and current input conditions were proposed.