• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.102-108
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• 2008

This study investigates the fatigue life and the damage possibility of cam shaft by the fatigue tool of Ansys. Among nonconstant fatigue loads, the case of 'SAE Bracket History' which is severest at the variation of load tends to be most unstable. The maximum relative damage in case of 'SAE Bracket History' is occurred near the average stress '0' and this case can be shown to have the possibility to take more damage than other cases. The case of 'Sample History' which becomes a little slow at the variation of load tends to be most stable. But there is most damaged possibility of 5% as 7 times at the range of mean stress from 0Pa to -104MPa and amplitude stress from 0MPa to 104MPa than the case of 'SAE Bracket History' or 'SAE Transmission'.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.2 s.146
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• pp.206-212
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• 2006

Structural reliability of electrical panels installed in naval vessels is of critical importance from structural performance viewpoint. The electrical panels may be exposed to vibration and fatigue loadings from internal and external sources as well as wave loadings which result into a crack and fracture due to the decrease of fatigue strength. It is also well known that welded joints including brackets within steel structures .such as vessels and bridges are vulnerable against such repeated loadings. This study introduces a preliminary result of the optimized shape of frame bracket consisting of electrical panels in navel vessels against fatigue loading and their fatigue life at brackets of electrical panels by means of hot spot stress and structural stress methods.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.625-642
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• 2000

The purpose of this study is to evaluate the effects of mechanical and thermal fatigue stress on the shear, tensile and shear-tensile combined bond strengths(SBS, TBS, CBS) in various orthodontic brackets bonded to human premolars with chemically cured adhesive(Ortho-one, Bisco, USA). Five types of commercially available metal brackets with various bracket base configurations of Photoetched base(Tomy, Japan), Non-Etched Foil Mesh base(Dentaurum, Germany), Micro-Etched Foil Mesh base(Ortho Organizers, USA), Chessboard base(Daesung, Korea), and Integral base(3M Unitek, USA) were used. Samples were divided into 3 groups, the first group was acted with shear-tensile combined loads($45^{\circ}$) of 200g for 4 weeks(mechanical fatigue stress), the second group was subjected to the 5,000 thermocycles of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ baths(thermal fatigue stress), and the third group was the control. Bond strengths were measured at the crosshead speed of 0.5mm/min. The cross-section of bracket base/adhesive interface and the fracture surface were examined with the stereoscope and the scanning electron microscope. The resin remnant on bracket base surface was assessed by ART(Adhesive Remnant Index). The obtained results were summarized as follows, 1. In static bond strength, Photoetched base bracket showed the maximum bond strength and Integral base bracket showed the minimum bond strength(p<0.05). In all brackets, shear bond strength(SBS) was in the greatest value and shear-tensile combined strength(CBS) was in the least value(p<0.05). 2. After mechanical fatigue test, Photoetched base bracket showed the maximum bond strength and Integral base bracket showed the minimum bond strength(p<0.05). In Photoetched base bracket and Micro-Etched Foil Mesh base bracket, shear bond strength(SBS), tensile bond strength(TBS) and shear-tensile combined strength(CBS) were decreased after mechanical fatigue test(p

• Journal of Acupuncture Research
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• v.18 no.2
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• pp.227-236
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• 2001

Objectives : This study was performed to evaluate the clinical results of the thoracolumbar fracture patients treated with oriental medical methods. Methods : We reviewed 40 patients of thoracolumbar fracture, who were hospitalized at WonKwang University KwangJu Oriental Medical Hospital and treated by oriental medical methods. We classified thoracolumbar fracture according to three column theory and then analyzed the cause of injury, sex-age distribution, treatment, and etc.. Results : 1. The distribution showed female predominance(72.5%) in sex and 70age-bracket predominance in age. 2. In the distribution of causes, the largest group was "lifting heavy objects"(40%) and the next was "slip down"(37.5%). 3. In the duration of symptoms, the largest group was the group of "acutest" (40%). 4. The distribution of injured level was L1 body the most(20%). 5. In classification of fracture, "compression fracture" was the most(57.5%) and the next was "burst fracture", "unstable fracture" in order. 7. Therapeutic effects above "fair" were 37 cases(92.5%). 8. The higher grade of clinical symptoms is, the lower therapeutic effect is. 9. In the distribution of treatment results according to classification of fracture, both the compression fracture and the burst fracture were almost same high and the unstable fracture is relatively lower than them. Conclusions : The result to treating thoracolumbar fracture by oriental medical methods is satisfactory.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.201-206
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• 2009

This study investigates fatigue life and possibility damaged at disk brake of automobile by the simulation of fatigue analysis. Among nonconstant fatigue loads, the case of 'SAE Bracket History' which is the severest at the variation of load tends to be most unstable. The case of 'Sample History' which becomes slower at the variation of load tends to be most stable. The value of maximum relative damage in case of 'SAE Bracket History' is occurred near the average stress '0' and this case can be shown to have the possibility to affect more damage than another case. As the result of this study is applied to automobile parts with non constant loads, durability can be improved during drive by preventing any damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2865-2871
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• 2012

In this study, the fracture behaviour of DCB(double cantilever beam) specimen with aluminum foam composite materials is analyzed by simulation. By comparing the analysis results with two models of 25 mm and 40 mm, the model with thickness of 25 mm is weaker than 40 mm at fatigue life and damage. Two models are unfavorable at 'SAE Transmission' in case of nonuniform fatigue load and rainflow matrices are weakest at 'SAE Bracket history'. In damage matrices, the model with 25 mm of thickness is weaker than the model with 40 mm of thickness but the model with 40 mm of thickness relative damage possibility is higher than in case of 25 mm. As two models are safest at 'SAE Transmission', the relative damage becomes the lowest value from 1.1 to 1.8 %. The mechanical property can be investigated by applying these analyses results with the real composite structure bonded with adhesive and analyzing fracture behaviour.

• Journal of Acupuncture Research
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• v.25 no.3
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• pp.29-39
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• 2008

Methods : We investigated 28 cases of patients with thoracolumbar compression fracture. We divided patients into two groups : We treated one group with complex oriental medical treatment focusing on Bee Venom Acupuncture therapy, and did the other group with complex oriental medical treatment focusing on acupuncture therapy. To investigate the effectiveness of treatment applied for two groups, we used Visual Analog Scale(VAS) and Oswestry Low-back Pain Disability Index(ODI). We compared the VAS score and ODI score of two groups statistically. Results : 1. Female is prominent in distribution of sex, the average age bracket is 70's, and the largest group was Faccidental fall in the distribution of cause. 2. In regard to level of injury, T12 was found to be most prominent, followed in turn by L1, L2. In regard to grade of clinical symptoms, Grade III was most prominent, followed by Grade IV, Grade II. 3. As a result of evaluation by using VAS score and ODI score, treatment score at final was significantly different from that at the baseline in each group. 4. After treatment, Bee Venom acupuncture therapy group showed significant difference on VAS score and ODI score compared with acupuncture therapy group. Conclusions : Bee Venom acupuncture therapy can be available for relieving symptoms related with thoracolumbar compression fracture.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.422-430
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• 1998

This paper presents the results of a major parametric study on the collapse cause of the Sungsoo Grand Bridge, a Gerber-type continuous truss bridge, which had collapsed just at the 15th year since opening to traffic. Among the various collapse causes such as poor design, poor welding, poor maintenance, and heavy traffic loads, this study focuses on the collapse cause assessment incorporating the effects of braket and H-beam members right below the expansion joint of the suspended truss. A local FEM analysis using fine shell elements is carrided out for the more precise estimation of stress range of the vertical pin-connected hanger whose fatigue fracture triggered the collapse of the bridge. Both the conventional S-N approach and the Ang-Munse's fatigue reliability method are used for the evaluation of the fatigue life and fatigue failure probability for the assessment based on all the available results of various field and labolatory tests. From these observations, It may be affirmatively stated that the effects of bracket and H-beam members accelerated the fatigue failure, and thus should be regarded as one of major causes that triggered the bridge collapse

• Journal of Acupuncture Research
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• v.26 no.1
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• pp.81-90
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• 2009

Objectives : This Study was to investigate the tendency of inpatient with Thoracolumbar Compression Fracture. Also we investigated effectiveness of Pharmacopuncture and Warming Acupuncture on Thoracolumbar Compression Fracture. Methods : We investigated 48 cases of patients with thoracolumbar compression fracture. We distributed inpatint with age, sex, number of injured vertebra, level of injured vertebra, admission duration, grade of clinical symptom, result of treatment and applied treatments. And we calculated statistically signification with this data. Results : 1. Female is prominent in distribution of sex, the average age bracket is 70's, and the largest group was accidental fall in the distribution of causes. 2. In regard to level of injury, T12 was found to be most prominent, followed in turn by L2, L1, T12. In regard to grade of clinical symptoms, Grade III was most Prominent, followed in turn by Grade IV, Grade II. In regard to grade of result of treatment, Good was most prominent. 3. There was not statistically significantly correlation about admission duration and result of treatment with number of injured vertebra, grade of clinical symptom, applied treatments. Conclusions : Most inpatients with thoracolumbar compression fracture was cured by oriental medicine treatment.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.59-65
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• 2018

The landing gear (L/G) handle of an aircraft is an essential piece of equipment for aircraft take-off and landing. The bracket in the landing gear handle was fractured during a vibration test when developing the landing gear handle. This paper summarizes the vibration test procedures performed during landing gear handle development. A cause analysis, design improvements, and verification results of the fault in the vibration test are also provided.