• Journal of Biomedical Engineering Research
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• v.36 no.2
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• pp.37-42
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• 2015

In this paper, we propose a wrist rehabilitation training device using pneumatic inflation and deflation of air cells. By alternating inflation and deflation of upper and lower air cells, the device makes the flexional and extensional movement for wrist rehabilitation. With the angular displacement sensor, it measures the flexion-extension angle of the wrist during the training and the bending angle is used for the automatic control of the device. Using the sensor output, the regression equation was obtained to measure the bending angle of the wrist from a wrist rehabilitation training device. The measurement error of the device was evaluated by comparing the measurement output with the angle from the photograph. The measurement error of wrist bending angle between the sensor and photo was $3.2^{\circ}$ in average. With additional test and improvement, the pneumatic wrist rehabilitation training device might be used for rehabilitation training.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.04a
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• pp.192-198
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• 2007

• Journal of Ocean Engineering and Technology
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• v.32 no.5
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• pp.297-309
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• 2018

After an accident involving mooring link failures in an offloading buoy, verification of the fatigue safety in terms of the out-of-plane bending (OPB) and in-plane bending (IPB) moments has become a key engineering item in the design of various floating offshore units. The mooring links for an 8 MW floating offshore wind turbine were selected for this study. To identify the OPB stiffness (OPB moment versus interlink angle), a numerical simulation model, called the 3-link model, is usually composed of three successive chain links closest to the fairlead or chain hawse. This paper introduces two numerical simulation techniques for the 3-link analyses. The conventional and advanced approaches are both based on the prescribed rotation approach (PRA) and direct tension approach (DTA). Comparisons of the nominal stress distributions, OPB stiffnesses, hotspot stress curves, and stress concentration curves are presented. The multiple link analyses used to identify the tension angle versus interlink angle require the OPB stiffness data from the 3-link analyses. A convergence study was conducted to determine the minimum number of links for a multi-link analysis. It was proven that 10 links were sufficient for the multi-link analysis. The tension angle versus interlink angle relations are presented based on multi-link analyses with 10 links. It was found that the subsequent results varied significantly according to the 3-link analysis techniques.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.162-169
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• 2005

The functional external fixator system fur bone deformity near joints in legs using the worm gear was developed for curing the difference angles in fracture bone and the lengthening bar for curing the difference length in fracture bone. Both experiments and FE analysis were performed to compare the elastic stiffness in several loading modes and to improve the functional external fixator system for the bone deformity. The FE model using the compressive and bending FE analysis was applied to the FE analysis due to the angle differences. The results show that the compressive stiffness value in experiment was 175.43N/mm; the bending stiffness value in experiment was 259.74N/mm; compressive stiffness value in FEM was 188.67N/mm; bending stiffness value in FEA was 285.71N/mm. The errors between experiments and FEA were less than 10%. The maximum stress (157MPa) to the angle of clamp was lower than the yield stress (176.4MPa) of SUS316L. The stiffnesses in both axial compressive and bending of the new fixator are about 2 times higher than other products except EBI (2003).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1248-1251
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• 2004

The functional external fixator system for bone deformity near joints in legs using the worm gear was developed for curing the difference angles in fracture bone and the lengthening bar for curing the difference length in fracture bone. Both experiments and FE analysis were performed to compare the elastic stiffness in several loading modes and to improve the functional external fixator system for bone deformity near joints in legs. The FE model using the compressive and bending FE analysis was applied the FE analysis due to the angle differences. The results show that the compressive stiffness value in experiment was 175.43N/mm, the bending stiffness value in experiment was 259.74N/mm, compressive stiffness value in FEM was 188.67N/mm, bending stiffness value in FEA was 285.71N/mm. The errors between experiments and FEA were less than 10％. The maximum stress (157MPa) to the angle of clamp was lower than the yield stress (176.4MPa) of SUS316L. The stiffnesses in both axial compressive and bending of the new fixator are about 2 times higher than other products except EBI (2003).

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.2
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• pp.50-57
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• 2019

This paper investigates deformation characteristics of gas pipeline using the in-plane bending experiment and finite element analysis of a pipe bend. The effect of the bending angle and internal pressure on the deformation characteristics is analyzed. The pipe bend used in this study is API 5L X65 (out diameter: 20 inch) material with the thickness of 11.9 mm. The maximum load, displacement at maximum load, angle and local strain of 90° pipe bend are obtained from the in-plane bending experiment. Comparison between FE results and experimental data shows overall good agreements. In addition, the deformation characteristics of 22.5° and 45° pipe bend are calculated using the finite element analysis. As a result, the effect of the bend angle on the deformation characteristics is discussed.

• The Journal of Korea Robotics Society
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• v.13 no.2
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• pp.92-96
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• 2018

In this paper, a soft robotic arm which can prevent impact injury during human-robot interaction is introduced. Two degrees of freedom joint are required to realize free movement of the robotic arm. A robotic joint concept with a single degree of freedom is presented using simple inflatable elements, and then extended to form a robotic joint with two degrees of freedom joint using similar manufacturing methods. The robotic joint with a single degree of freedom has a joint angle of $0^{\circ}$ bending angle when both chamber are inflated at equal pressures and maximum bending angles of $28.4^{\circ}$ and $27.1^{\circ}$ when a single chamber if inflated. The robotic joint with two degrees of freedom also has a bending angle of $0^{\circ}$ in both direction when all three chambers are inflated at equal pressures. When either one or two chambers were pressurized, the robotic joint performed bending towards the uninflated chambers.

• Journal of the Korea Institute of Building Construction
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• v.15 no.5
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• pp.465-471
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• 2015

This study proposed V-shaped tie bar method as an alternative of internal cross-tie for reinforced concrete columns in order to enhance the constructability and confinement effectiveness of the lateral tie bars. A total of 35 pull-out specimens were prepared with the parameters of concrete compressive strength and bending angle and embedment length of the V-shaped bar to examine the bond stress-slip relationship of the V-shaped tie bar. The bond strength of the V-shaped tie bars with the bending angle not exceeding $60^{\circ}$ was higher than the predictions obtained from the equations of CEB-FIP provision. Considering the constructability and bond behavior of the V-shpaed tie bar, the bending angle and embedment length of such bar can be optimally recommended as $45^{\circ}$ and 6db, respectively, where db is the diameter of the tie bar.

• Journal of Biosystems Engineering
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• v.26 no.6
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• pp.563-570
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• 2001

To develop a stalk detaching system the effect of shape factor of red pepper affecting the performance of unfolding, arranging and cutting was analysed. The obtained results are as follows : By cutting experiment, it was found that the bending of stalk affected the cutting rate of stalk, and that the bending of body increased the amount of peppers that were expelled from the cutting guide by conveying brush. The ratios, 'bending length of a body/body length'and 'bending length of a stalk/stalk length', could be used as criteria far abnormality of body and stalk of peppers, respectively. As a result of experiment, it was concluded that mechanical treatment would be difficult for the peppers with indexes greater than 0.4 and 0.3 fur body bending and stack bending. respectively. So, these indexes were used as criteria for distinguishing abnormality from normality of peppers. In the unfolding unit, conveyance of peppers was impossible for both of normal and abnormal ones at the inclination angle of 10°, especially, at the frequency of 8.3 Hz peppers maintained stationary state. At the inclination angle of 20°, both of normal and abnormal peppers showed similar tendencies, but abnormal ones showed an accumulation trend gradually with increased feeding speed. In the arranging unit, conveyance of peppers was almost impossible for both of normal and abnormal ones at the inclination angle of 20°, showing almost no difference between the conveyances of normal and abnormal ones. In the case of the inclination angle of 30°, at the condition of the feeding speeds and frequency corresponding 0.06 m/s, 0.08 m/s and 8.3 Hz, respectively, the passing time of the abnormal peppers on the arranging plate increased rapidly.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.410-413
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• 1997

Recent general press brake has many problems in cutting high accurate products in the progress of industry. Previous hand-operated press brake needs many pre-processing works to adjust bending angle and marking-off works to calculate bending length. Also, The hand-operating work makes many geometric errors and has difficulty for variety-mass production. To solve these problems, this paper proposes Computer Numerical Control (CNC) general press brake and development of servo-control system based on database for reduction of geometric errors and pre-processing work time.