• Composites Research
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• v.24 no.2
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• pp.22-29
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• 2011

To increase the performance of thick-walled cylinders recently their length is continually enlarged. For that reason it is important to reduce weight of the thick-walled cylinders. In this paper the FE models to predict and estimate effects on the composite tapes were created with MSC.Nastran/Patran v.2005. First of all a autofrettage method was applied to the 2D model of the AISI4340 cylinder reduced the thick. And then the comparison of the numerical results with analysis results showed and verified by using T300/5208, IM7/PETI5, IM7/8552 tapes. Those are predicted to the effects of the angle of the composite tapes and elastic modulus according to the composite properties.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.1
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• pp.41-48
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• 1998

An investigation made of the easing contraction ratio according to sewing conditions (eased seam angle; 0$^{\circ}$ 20$^{\circ}$ 30$^{\circ}$ 45$^{\circ}$ 60$^{\circ}$ 70$^{\circ}$ 90$^{\circ}$, stitch density; 38 stitches/3 cm(N1.0), 26 stitches/ 3 cm(N1.5), 19 stitches/3 cm(N2.0), 14 stitches/3 cm(N2.5), 12 stitches/3 cm(N3.0), thread; sp 60' s/2) by lockstitch industrial sewing machine with shirring foot. The results abstained were as follows: 1. The lower the stitch density , the higher the easing contraction ratio. 2. The easing contraction ratio at 0$^{\circ}$ and 90$^{\circ}$ were lower than bias angles (20$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$, 70$^{\circ}$). 3. As the results of visual test, the maximum easing conditions were Fl -0$^{\circ}$.20$^{\circ}$.30$^{\circ}$.45$^{\circ}$-12 stitches/3 cm(N3.0), 60$^{\circ}$. 70$^{\circ}$. 90$^{\circ}$-14 stitches/3 cm(N2.5), F2 -0$^{\circ}$. 20$^{\circ}$.30$^{\circ}$.60$^{\circ}$.70$^{\circ}$.90$^{\circ}$-19 stitches/ 3 cm(N2.0), 45$^{\circ}$ -14 stitches/3 cm(N2.5), and F3 -0$^{\circ}$.20$^{\circ}$.30$^{\circ}$.45$^{\circ}$.60$^{\circ}$.70$^{\circ}$.90$^{\circ}$-19 stitches/3 cm (N2.0). 4. Approximately easing contraction ratio was obtained as 2.0% (N1.0)~ 10.2% (N3.0) in F1, 6.7% (N1.0)~ 15.7% (N2.0) in F2, and 5.2% (N1.0)~ 12.1% (N2.0) in F3, according to different angles on the sleeve cap curve line. 5. As a resets of SPSS PC) statistics analysis, it confirmed the relations which were observed between easing contration ratio and stitch density, and easing contraction ratio was correlated with bending properties.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.3
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• pp.576-585
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• 2002

A three-dimensional Lagrangian explicit time-integration finite element code for analyzing the dynamic impact phenomena was developed. It uses four node tetrahedral elements. In order to consider the effects of strain rate hardening, strain hardening and thermal softening, which are frequently observed in high-velocity deformation phenomena, Johnson-Cook model is used as constitutive model. For more accurate and robust contact force computation, the defense node contact algorithm was adopted and implemented. In order to evaluate the performance of the newly developed three-dimensional hydrocode NET3D, numerical simulations of the oblique impact of mild steel plate by mild steel sphere were carried out. Ballistic limit about various oblique angle between 0 degree and 80 degree was estimated through a series of simulations with different initial velocities of sphere. Element eroding by equivalent plastic strain was applied to mild steel spheres and targets. Ballistic limits and fracture characteristics obtained from simulation were compared with experimental results conducted by Finnegan et al. From numerical studies, the following conclusions were reached. (1) Simulations could successfully reproduce the key features observed in experiment such as tensile failure termed "disking"at normal impacts and outwards bending of partially formed plus segments termed "hinge-mode"at oblique impacts. (2) Simulation results fur 60 degrees oblique impact at 0.70 km/s and 0.91 km/s were compared with experimental results and Eulerian hydrocode CTH simulation results. The Lagrangian code NET3D is superior to Eulerian code CTH in the computational accuracy. Agreement with the experimentally obtained final deformed cross-sections of the projectile is excellent. (3) Agreement with the experimental ballistic limit data, particularly at the high-obliquity impacts, is reasonably good. (4) The simulation result is not very sensitive to eroding condition but slightly influenced by friction coefficient.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.147-158
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• 2004

For stiffened plates composed of composite materials, many researchers have used a finite element method which connected isoparametric plate elements and beam elements. However, the finite element method is difficult to reflect local behavior of stiffener because beam elements are transferred stiffness for nodal point of plate elements, especially the application is limited in case of laminated composite structures. In this paper, for analysis of laminated composite stiffened plates, 3D shell elements for stiffener and plate are employed. Reissner-Mindlin's first order shear deformation theory is considered in this study. But when thickness will be thin, isoparamatric plate bending element based on the theory of Reissner-Mindlin is generated by transverse shear locking. To eliminate the shear locking and virtual zero energy mode, the substitute shear strain field is used. A deflection distribution is investigated for simple supported rectangular and skew stiffened laminated composite plates with arbitrary orientation stiffener as not only variation of slenderness and aspect ratio of the plate but also variation of skew angle of skew stiffened plates.

• The Journal of Korean Physical Therapy
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• v.13 no.2
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• pp.265-272
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• 2001

The object of this thesis is to study the correlation between scoliosis and foot in a theoretical and empirical method. My research process was investigated for 34 students on the forward bending test, foot printer test, feedoscope test, X-ray test and so on. The main results of this study were as follows: 1. There was statistical significance on the correlation between foot length and spine length. 2. Scoliosis angle is the smallest on the pes plannus group and the biggest on the pes cavus group without statistical significance. 3. Left lumbar curve is the smallest, and right thoracic spine curve is the biggest on the left foot pattern group with statistical significance. 4. On the foot weightbearing groups, there was statistical significance both of between left and right foot groups. 5. There was no statistical significance on the t-test analysis between left foot area and right foot area according to scoliosis typology.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.83-90
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• 2010

The purpose of this study is to validate that change of impact by the Early Extension in during a golf driver swing. 13 golf players who were diagnosed with symptoms of Early Extension participated in a proactive corrective training programs that took place 3 times a week for a 4 month period. Data was collected by recording 5 pre and 5 post training driver swings and analyzing the data to calculate the change in velocity and its effect in the shot used the TRACK MAN. After the training, the changes of early extension were -0.21 cm in backswing section E2(take away), -0.64 cm in E3(halfway backswing), and -0.94 cm in E4(backswing top). The downswing section changes were -1.34 cm in event E5(halfway downswing), -1.74 cm in E6(impact). Impact force increased and thus club speed increased by 6.32 km/h, ball speed increased by 10.94 km/h, max height decreased by -6.22 m, carry increased by 10.85 m, carry side(left deviation) decreased by 4.84 m, flight time by increased by 0.4 sec, and total length increased by 17.96 m while landing angle decreased by -7.74 deg.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1207-1210
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• 2004

As many humans age, degenerative lumbar spinal stenosis (DLSS) becomes a major cause of lower limb discomfort and disability. By surgical treatment method of DLSS, the existing surgical treatment methods using internal fixation have showed degeneration changes of an adjacent vertebrae and loss of lumbar spine lordosis-kyphosis due to eliminating a motion. For solving the problems of internal fixation, a novel interspinous spacer has been developed to treat DLSS by surgical treatment method. In this study, we evaluated the biomechanical effects of the interspinous spacer on the kinematics of the porcine lumbar spine before and after insertion of the implant. For this purpose, a device that is capable of measuring 3-D motions were built based on direct linear transformation (DLT) algorithm written with MATLAB program. Results showed that in extension, a change of the mean angle between the intact and the implanted specimens at L4-L5 was 1.87 degree difference and the implant reduced the extension range of motion of the L4-L5 (p＆lt;0.05). But the range of motion in flexion, axial rotation and lateral bending at the adjacent segments was not statistically affected by the implant. In conclusion, we thought that interspinous spacer may have remedical value for DLSS by flexing human lumbar spine.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.1
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• pp.50-66
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• 2010

This Shanghai region study is a sample survey of female college students in their early 20s. This study collected and analyzed the information of shapes through a direct contact survey to understand the breast figures and the measurements of bodies to provide basic information to improve brassiere production for adult females in China. Data was analyzed through a SAS 9.0. The characteristic of the final brassiere pattern that had been corrected and complemented from the results of the $l^{st},\;2^{nd},\;3^{rd}$, and $4^{th}$ fitting tests is defined as a brassiere inserted with a round wire that has the 3/4cup to wrap the bust area by about 3/4. It consists of an upper and lower nonwoven fabric cup that has a flat-shaped wing of a circular dart. The drawing method of the pattern of this brassiere is applied with the conditions to cover the body naturally under the diverse and organic relations of the material factor of stretch material and wire, functional factor, and sewing factor. The final pattern is created as a bigger angle of wing pattern and a short inner side diameter because there are more Chinese women with a back of bending figure compared to Korean women.

• Journal of Korean Society of Steel Construction
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• v.29 no.2
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• pp.135-145
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• 2017

This study is a secondary study that is a cyclic seismic test of High depth hybrid composite beam and column connection after the primary bending strength test of a high depth Hybrid composite beam. Total of 3 seismic test specimens were prepared to cyclic test. The bracket and beam web spliced by high strength bolt and the bracket and beam upper flange was spliced by welding. Test results showed that the seismic strength was higher than the plastic moment($M_p$) in the positive negative moment section, the requirement of composite intermediate moment frame wes satisfied. Therefore, the requirement of intermediate moment frame can be secured by applying the details of connection of this study results.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.534-538
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• 2015

Objective : To correct apical vertebral rotation for adolescent idiopathic scoliosis (AIS), direct vertebral derotation (DVD) or simple rod rotation (SRR) might be considered. The aim of the present study is to introduce the surgical experiences of AIS by a Korean neurosurgeon and to evaluate the effectiveness of SRR for apical vertebral rotation. Methods : A total of 9 patients (1 male and 8 females) underwent scoliosis surgery by a neurosurgeon of our hospital. The Lenke classifications of the patients were 1 of 1B, 2 of 1C, 1 of 2A, 1 of 2C, 3 of 5C and 1 of 6C. Surgery was done by manner of simple rod rotation on the concave side and in situ coronal bending. Coronal Cobb's angles, vertebral rotation angles and SRS-22 were measured on a plain standing X-ray and CT before and after surgery. Results : The mean follow up period was 25.7 months (range : 5-52). The mean number of screw positioning level was nine (6-12). The mean age was 16.4 years (range : 13-25) at surgery. The mean Risser grade was $3.7{\pm}0.9$. The apical vertebral rotation measured from the CT scans was $25.8{\pm}8.5^{\circ}$ vs. $9.3{\pm}6.7^{\circ}$ (p<0.001) and the Coronal Cobb's angle was $53.7{\pm}10.4^{\circ}$ vs. $15.4{\pm}6.5^{\circ}$ (p<0.001) preoperatively and postoperative, respectively. The SRS-22 improved from 71.9 preoperatively to 90.3 postoperatively. There were no complications related with the operations. Conclusion : SRR with pedicle screw instrumentation could be corrected successfully by axial rotation without complications. SRR might serve as a good option to correct AIS deformed curves of AIS.