• Fibers and Polymers
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• v.7 no.1
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• pp.79-84
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• 2006

This paper deals with the grey fabric deformation during relaxation. It investigates the effect of twist direction and twist liveliness on the 2/2 twill weave woven fabric distortion, during relaxation This experimental work shows that twist liveliness increases the natural tendency of the twill weave woven fabric to skew. In addition when the twist direction of the warp and weft is opposite to each other the bias curling occurs too.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.7-14
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• 2011

The numerical analyses were performed to investigate the curling behavior of the post-tensioned prestressed concrete approach slab (PTAS) under environmental loads. A technique to include properly the boundary conditions of one end of PTAS that was connected to the bridge abutment using hinges was proposed for the numerical model. The applicability of a simplified model not having hunches was also investigated. By using the developed models, the curling behavior of PTAS was analyzed when the foundation settlement occurred. The analysis results showed that the maximum tensile stress obtained from the simplified model involving a simplified hinge connection was very closed to that obtained from a rigorous model. When the slab curled up, the maximum tensile stress occurred in the model including no foundation settlement, but when the slab curled down, the maximum stress occurred in the model including partial settlement of the foundation. Therefore, the design of PTAS should be performed considering those maximum tensile stresses.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.209-220
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• 2008

This paper presents the differences in the analysis results according to the underlying layer modeling methods when analyzing the curling behaviors of the concrete slabs on grade under environmental loads. The models of the slab on grade system considered in this study included a three-dimensional(3D) model, a model composed of 3D slab and springs for underlying layers, and a model composed of 2D slab and springs for underlying layers. First, when the underlying layer consisted of one layer, the curling behaviors according to the different models were compared. Then, the underlying layers that consisted of two different materials and thicknesses were considered. The results of this study showed that the tensionless spring model for the underlying layer gave very accurate results when the underlying layer consisted of one layer. However, when the underlying layers consisted of two layers, the spring model for the underlying layers could overestimate the displacements and underestimate the maximum stress with a large elastic modulus of upper underlying layer, a small elastic modulus of under underlying layer, and thick underlying layers.

• Journal of Korean Society of Steel Construction
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• v.23 no.1
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• pp.29-39
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• 2011

With regard to steel construction, many studies have been performed to examine the structural behavior of the bolted connections domestically and in other countries. Especially, a domestic study was conducted on the block shear fracture and shear lag effect on the single-bolted angle connection in carbon steel. In this study, specimens were prepared with the end distance parallel to the loading direction and bolt arrangement ($1{\times}1$, $1{\times}2$), as the main variables. Then the fracture mode and the curling effect on the bolted angle connection in austenitic stainless steel were investigated. Moreover, the fracture mode and ultimate strength were compared, and the strength reduction by curling was estimated.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.49-56
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• 2017

Curling sweeping is one of important motion to control the position of the curling stone, and sweeping speed and applied force to the broom pad are major research subjects. In this study, a device was developed to measure the force applied to the curling broom pad in curling sweeping motion, and two load cells were mounted between the broom pad and pad holder. Analog signals generated from the load cells were sampled about 300 times per second using a micro controller, and then converted to 10-bit digital signals. Calibration of the load cell and set up of regression equations to convert the measured electrical signals into mass (force) was done by three M1 class weights, and the developed system was designed as wearable device to minimize increasing of total weight of the broom. Same force was applied to the developed system and a force plate that was using as a reference force measurement system in field of sports, and the difference between the measured values were showed about $0.909{\pm}1.375N$(mean and standard deviation). The developed system could be applied other kinds of study which required force measurement function similar to sweeping motion.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.275-290
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• 2019

The present study aimed to develop a sports psychological skill training program and to test its applicability to improve the performance of national wheelchair curling players. A total of 4 participants completed the study. Subjects have been to 12 sessions of 6 different psychological skills training programs (routine training, attentional focus training, writing practice training in diary, relation training, self-control training, and positive self-talk training). The effectiveness of psychological skills training has been evaluated with 6 questionnaires and EEG measurement. The result was that psychological skills training had improved coping with adversity, peaking under pressure, and concentration, self-management and reduced anxiety of Korean national wheelchair curling player. The result was that the EEG inter-hemispheric asymmetry index showed negative emotional states before psychological skill training but positive emotional states after. The result implies that psychological skill training plays an important mediating role in bringing about positive effects in the psychological elements and competitiveness in national wheelchair curling players.

• 한국도로학회:학술대회논문집
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• 2006.10a
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• pp.149-152
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• 2006

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.431-434
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.891-894
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• 2001

In this work, an effort is made to investigate the behavior of a chip, from its initial flow to its final breaking stage. The expression for chip flow in grooved tools is verified analytically using FEM. Cutting parameters like velocity and depth of cut have a profound influence on chip flow behavior. Chip curling increases and, for a given tool geometry, effectiveness of the groove increases with increasing depth of cut. The feasibility of tool design using FEM simulations is also demonstrated. Optimization of tool geometry results in better chip control.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.790-796
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• 2012

Chip curling occurred during cutting process for difficult-to-cut material detracts product qualities and productivity. Among of method preventing the phenomenon, high pressure injecting cutting oil is an alterative. In this study, the optimal nozzle was designed by CFD method and it was conducted to analyse on the effect of high pressure injection on chip shape generated during cutting process and wear of insert by experimental method. As the result, it could be confirmed that high pressure injection is favorable for preventing chip curling and insert from wearing.