• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.647-648
• /
• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.1025-1026
• /
• 2013

• Journal of the Korean Society of Safety
• /
• v.5 no.2
• /
• pp.24-31
• /
• 1990

In this study, the bending and twisting stiffnesses of corrugated plate were analyzed by applying equivalent idea, and the optimum shape of corrugated plate was determinated in the stiffnesses.

• Journal of the Korean Society of Safety
• /
• v.8 no.4
• /
• pp.21-26
• /
• 1993

This paper presents a method of stress analysis of golf club. We define the sweet spot of golf club by the magnitude of torsional moment. Transfer matrix method was used for optimal design on sweet spot of golf club.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.2
• /
• pp.349-356
• /
• 2011

Objective: The purpose of this study was to analyze the risk factors of the musculoskeletal workload of mid-old-age female caregivers by identifying work postures and subjective symptoms. Method: This study was carried out on a total of 206 subjects 206 mid-old-age caregivers(45~65 years old) from November 2009 to April 2010: 206 mid-old-age caregivers (45~65 years old) at the long-term hospital. A questionnaires survey on general factors and subjective symptoms of subjects was conducted. The risk factors of the musculoskeletal workload evaluation method is based on OWAS, RULA, REBA according to occupation properties. Results: The analysis of the rates of the subjective symptoms showed that 78.6% subjects experience low back pain. The analysis of the work type showed that transfer is the highest rate(36.3%) and position change is the second(18.2%). The analysis of the work postures showed that the thrusted back with twisting position over $20^{\circ}$ is highest rate(37.4%), the bended back forward with twisting position is the second(27.5%). Conclusion: This study suggested that the need of preventive education for caregivers and workload improve. It is hoped that subsequent study on the difference of subjective symptoms between educated caregivers and non educated caregivers will be conducted.

• Steel and Composite Structures
• /
• v.3 no.4
• /
• pp.261-275
• /
• 2003

Truss members built-up with double angles back-to-back have monosymmetric cross-section and twisting always accompanies flexion upon the onset of buckling about the axis of symmetry. Approximate formulae for calculating the buckling capacity are presented in this paper for routine design purpose. For a member susceptible only to flexural buckling, its optimal cross-section should consist of slender plate elements so as to get larger radius of gyration. But, occurrence of twisting changes the situation owing to the weakness of thin plates in resisting torsion. Criteria for limiting the leg slenderness are discussed herein. Truss web members in compression are usually considered as hinged at both ends for out-of-plane buckling. In case one (or both) end of member is not supported laterally by bracing member, its adjoining members have to provide an elastic support of adequate stiffness in order not to underdesign the member. The stiffness provided by either compression or tension chords in different cases is analyzed, and the effect of initial crookedness of compression chord is taken into account. Formulae are presented to compute the required stiffness of chord member and to determine the effective length factor for inadequately constrained compressive diagonals.

• Transactions of Materials Processing
• /
• v.14 no.5 s.77
• /
• pp.444-451
• /
• 2005

A new extrusion process of the circular section product with helical fins could be developed by rotating extrusion die. The twisting of extruded product is caused by the twisted conical die surface connecting the die entrance section and the die exit section linearly. But, until now, because the process has used fixed extrusion die, it needs high pressure in order to twist billet and form fin shape on the surface of billet. So, during extruding billet, in order not to twist billet, the extrusion die is needed to rotate itself instead of twisting of billet. It is known that it is possible to reduce extrusion load of product with helical fins by analysis and experiments using rotating die. And it is known that, through the extrusion load analysis by $DEFORM^{TM}-3D$ software, optimal rotational velocity of rotating die can be obtained according to reduction ratio of area and twisted angle of die. And experiments and analysis using rotating extrusion die show that the twisted angle of product can be controlled by twisted angle of extrusion helical die and the rotational velocity of extrusion helical die.

• Computational Structural Engineering
• /
• v.9 no.4
• /
• pp.135-140
• /
• 1996

Single angle or channel with thin-walled open section can be used as compression member for example as web member in truss. In this case the inevitable eccentricity due to fabrication is commonly neglected in structural design. However eccentricity effect should be considered in the member design, especially in case of compression member. The critical loads of compression members that buckle by twisting or by a combination of bending and twisting are to be determined by solving governing differential equations. In this paper, the investigations are limited to the rolled channels([), equal-leg angles(L), lipped channels(C) and the applied loads are assumed to have some eccentricities.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.11
• /
• pp.1871-1884
• /
• 1997

This paper describes the design process of a 3-component load cell with a multiple parallel plate structure which may be used to measure transverse forces and twisting moment simultaneously. Also we have derived equations to predict the bending strains on the surface of the beams in the multiple parallel plate structure under transverse force or twisting moment. It reveals that the bending strains calculated from the derived equations are in good agreement with the results from finite element analysis and experiment. Also we have evaluated the rated output and interference error of each component, which can be efficiently used to design a 3-component load cell with a multiple parallel plate structure.

• Textile Coloration and Finishing
• /
• v.31 no.4
• /
• pp.332-340
• /
• 2019

Due to the change in lifestyle, new sensible materials for sportswear and outdoor are needed. This study is conducted in order to obtain the data for sensible materials through nylon twist process. 1-step nylon twisting machine was used to set the optimum twist process. DSC measurements of twisted nylon yarn showed crystallization temperatures around 170℃ and melting temperatures around 220℃. Nylon 40D/13F DTY and Nylon 50D/48F DTY showed optimal results at 160℃, 1,500 T/M(Turns per meter), and Nylon 70D/68F DTY at 160℃, 1,200 T/M(Turns per meter) after 1-step twist process. Also, Nylon 40D/13F DTY was confirmed to have inter-layer property deviation of ±5 percent.