• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1897-1900
• /
• 2005

The purpose of this study is to investigate the bending process for manufacturing of sound pipe by 3 dimension bending machine. The arbitrarily-bended pipe is widely used in a heat exchanger system. The pipe should be formed precisely for assembling of heat changer. And, spring back effect and variation of the pipe thickness should be controlled effectively. We described the change of spring back amount and thickness variation of the pipe according to the change of bending radius and bending angle by FEM analysis. The analysis is adopted the elasic-plastic analysis and contact analysis on MARC software.

• Transactions of Materials Processing
• /
• v.18 no.7
• /
• pp.531-537
• /
• 2009

The effect of blank holding force on thickness variation in simultaneous sheet forming with rectangular shape and circular has been demonstrated. Because has investigated an effect on formability of magnesium sheet, in this paper, the effect of punch radius on formability have been thinning, various crack phenomena and forming velocity. By simultaneously forming process with circular and rectangular shape, the data of simultaneously forming process with circular and rectangular shape will used to a part development such as notebook computer case, cell phone and bipolar plate of fuel cell.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.4
• /
• pp.50-56
• /
• 2011

Injection molding process is one of the popular manufacturing methods to produce plastic parts with high efficiency and low cost. Ball seat for automobile suspension is made by an injection molding process as a part to support pivot function of ball joint consisted of ball stud and housing. It is necessary for a ball seat to have a dimensional stability in the three dimensional inner area to be contacted with ball stud. In this paper, the dimensional stability of inner surface is indirectly analyzed by checking the difference of inner diameter around the circumferential direction and the thickness variation at the top part of ball seat. Measurement was performed by using the coordinate measuring machine and the fixture to hold ball seat. Optimization of injection molding processes such as injection time, cooling time and temperatures of cylinder barrel was derived to reduce the difference of inner diameter and the thickness variation at the top part of ball seat based on the Taguchi method.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.10 no.2
• /
• pp.100-106
• /
• 2010

The impact of surface quantization on device parameters of a Si metal oxide semiconductor (MOS) capacitor has been analyzed in the present work. Variation of conduction band bending, position of discrete energy states, variation of surface potential, and the variation of inversion carrier concentration at charge centroid have been analyzed for different gate voltages, substrate doping concentrations and oxide thicknesses. Oxide thickness calculated from the experimental C-V data of a MOS capacitor is different from the actual oxide thickness, since such data include the effect of surface quantization. A correction factor has been developed considering the effect of charge centroid in presence of surface quantization at strong inversion and it has been observed that the correction due to surface quantization is crucial for highly doped substrate with thinner gate oxide.

• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.11
• /
• pp.323-326
• /
• 1996

Dental implant is increasingly used to recover the mastication function of tooth. Several types of implant were designed to give an optimal stress distribution in surrounding bony regions. In this study, six types of implant were investigated using finite element method and it was studied i) how the variation of cortical bone thickness affects the stress distribution in surrounding bony regions depending upon implant types, ii) which type gives the best characteristics in the sence of stress distribution and stability. The hybrid-type implant with cylinder and screw gave the optimum properties in view of stability and response to the variation of cortical bone thickness.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.3667-3671
• /
• 2015

Through experiment that does not cause wrinkles in the forming process for the primary purpose for install PCB(Printed circuit board) the thickness variation of the material was investigated. Experimental results was showed that the forming height of the first process had Influence Material thickness variation in the second process, in the first process, the Entrance corner of the die must have round of the product height of 50%, and The height of forming should be as high as the thickness of the material than the original forming. Also as do implement the forming shape in the first process, the thickness of the material is thinned to 85%, Restriking in the second process was that The thickness of the material is thinned to 80%. Therefore, In order to implement a precise shape, Thinking that the material thinning, The die was maintain the shape of the original product, and It was obtain the effect of the compression that the punch is to be longer, as the sum of more than 20% of the material thickness in the depth of the original product.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.4
• /
• pp.58-71
• /
• 1989

This study aims to develop a computerized program for analysis of the ground-supported cylindrical shell structure with step varied section and to find out its mechanical characteri- stics through application of the developed program to the analysis of a ensiled farm silo as a model structure. The thickness of wall and bottom-plate of farm silo is assumed to be step-varied and its detailed structural dimensions are presented in Tab. 1 and 2. Several numerical case studies show that sectional stresses of the sample structures are largely reduced by adopting "varied section" design technique. And, other major results ob- tained from this study are summarize4 as follows ; 1. The variation of wall-thickness has a great influence on bending stresses of wall. Ho- wever, the larger the relative thickness of bottom-plate is, the smaller the influence is. 2. The magnitude of thickness of projecting toe of bottom-plate has negligible effect on sectional stresses 3. The conventional design methodology, which assumes the bottom edge of wall as clam- ped on ground, is proved to be discarded through the numerical analysis. 4. It is found that the "varied section" design technique should get similar effects as in the case of thick bott6m-plate having uniform thickness. 5. The variation of wall-thickness has a considerable effect on the bending stresses of bo- ttom-plate. Especially, this phenomenon is very remarkable in its projecting toe. In some cases. the negative bending moment may be acted on.

• Journal of the Korean Society of Physical Medicine
• /
• v.8 no.2
• /
• pp.231-238
• /
• 2013

PURPOSE: The purpose of this study is to find out the thickness variation of the superficial and deep abdominal muscles by measuring the thickness of the abdominal muscles. METHODS: 35 young, healthy adults(24 mens and 11 womens) participated in this study. The first, when only bridge exercise we had measured the thickness of their abdominal muscles by the ultrasound. The second, when the abdominal drawing-in during maintaining the bridge exercise we had measured the thickness of their abdominal muscles by the ultrasound. A pared t-test was used to determine a statistical significance for the thickness variation of the superficial and deep abdominal muscles. RESULTS: Results of before and after comparative analysis. The surperficial muscles(rectus abdominis, external obilique) statistically significantly reduced in the thickness and the deep muscle(transeverse abdominis) statistically significantly increased in the thickness. CONCLUSION: We have shown that the abdominal drawing-in exercise during maintaining the bridge exercise was effective to increase in strengthening abdominal deep muscle selectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.735-738
• /
• 2005

Electro-Active Paper (EAPap) is attractive as an EAP actuator material due to its merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and low power consumption. This paper presents the performance of EAPap actuators with thickness variation. The EAPap is made with cellulose paper, and is shown to bend in response to an external electric field. Up to the present, we have tested displacement, current and force of EAPap with 20 $\mu$m thickness. The thickness of EAPap is important factor that affects the performance of the actuator. Therefere, three different thickness of EAPap, 20, 30, and 40 $\mu$m are investigated that inference the tip displacement, blocked force, the resonance and the actuator efficiency. There is an optimum thickness of EAPap, which is resulted from the stiffness and the mass. The performance of EAPap with thickness is discussed.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.8
• /
• pp.188-195
• /
• 2004

In this paper we analyzed the mechanical behavior with respect to the thickness variation of elastic foundation(fatty tissue) in end-to-end anastomosis. This study considered the preliminary deformed shape induced by suturing in the anastomosis of coronary artery and PTFE with different diameters using simplified suturing model and the fatty tissue surrounding heart and coronary artery for more accurate result using finite element method. Area compliance(CA) was used to analyze the final deformed shape of the anastomotic part with respect to the thickness variation of fatty tissue under mean blood pressure, 100mmHg(13.3㎪). And Equivalent and circumferential stresses in the anastomosis were also analyzed with respect to the change of initial diameter ratio( $R_1$) and fatty tissue thickness( $T_{F}$). The results obtained were as follows : 1 When the elastic foundation, assumed to be incompressive material, surrounded the grafts in anastomosis, the compliance mismatch of artery and PTFE was reduced by 47 -72%. 2. As the initial diameter ratio( $R_1$) became larger, the higher difference of compliance was induced in spite of elastic foundation surrounding grafts. 3. The maximum nondimensional circumferential stress is twice or three times as high as the maximum nondimensional equivalent stress in the anastomotic part.t.