• Title/Summary/Keyword: joint stability

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Investigation of soldered low-resistance joints for coated conductors

  • Balashov, N.N.;Degtyarenko, P.N.;Ivanov, S.S.
    • Progress in Superconductivity and Cryogenics
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    • v.17 no.1
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    • pp.25-27
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    • 2015
  • The experimental investigation of resistance and thermal impacts stability of coated conductor joints has been carried out. We measured resistances of solder layers with the thicknesses ca. 10, 20, 30 and $40{\mu}m$ and additionally studied their stability against thermal impacts. The obtained results show a high quality of this joints and their applicability, e.g., for design of current leads in various superconductive energy applications.

Structural Design on Joint Component of Composite Wing of WIG Craft

  • Lee, Younggyu;Park, Hyunbum
    • International Journal of Aerospace System Engineering
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    • v.8 no.2
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    • pp.1-3
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    • 2021
  • This study proposed a specific preliminary structural design procedure of the main wing for a small scale WIG vehicle to meet the target weight of the system requirement. The high stiffness and strength Carbon-Epoxy material was used for lightness, and the foam sandwich type structure at the upper skin and the spar webs was adopted for improvement of structural stability. After structural design, wing joint part was designed. Through investigation on structural design result, design modification was performed. After design modification, even thought the designed wing weight was a little bit heavier than the target wing weight, the structural safety and stability of the final design feature was confirmed.

A Comparison of Barton-Bandis Joint Model and Mohr-Coulomb Joint Model for Tunnel Stability Analysis with DEM (개별요소법을 이용한 터널 안정성 해석에 있어 Barton-Bandis 절리 모델과 Mohr-Coulomb절리 모델의 비교)

  • 이성규;김치환
    • Tunnel and Underground Space
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    • v.11 no.2
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    • pp.167-173
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    • 2001
  • The joint model has influence on the results of discontinuum analysis. In this study the results of discontinuum analysis with Barton-Bandis joint model(BB model) and with Mohr-Coulomb joint model(MC model) are compared. The results of continuum analysis under the same condition are compared with the results of discontinuum analysis to investigate the behavior of rockmass around tunnel. The result of continuum analysis and that of discontinuum analysis with BB model show similar distribution of displacement and stress. On the other hand, the discontinuum analysis with MC model shows different displacement distribution and stress distribution. Moreover, the displacement and minor principal stress of the discontinuum analysis with MC model are smaller than those of continuum analysis, although the joints are explicitly considered in the discontinuum analysis. These results are originated from the limitation of MC model in simulating joint deformation behavior, especially the assumption of constant dilation jingle independent of it)int 7hear displacement.

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Effects of Floss Bands on Ankle Joint Range of Motion and Balance Ability

  • Moon, Byoung-Hyoun;Kim, Ji-Won
    • Physical Therapy Korea
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    • v.29 no.4
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    • pp.274-281
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    • 2022
  • Background: The range of motion (ROM) and balance ability of the ankle joint affect the stability of the ankle and prevent injuries or hurts from falling. In the clinical tests conducted recently, the floss band is widely used to enhance the range of joint motion and exercise performance, and there are many studies that have applied it to ankle joint increasing dorsi flexion (DF) angle. Objects: This study compared the effects on the range of ankle motion and static/dynamic balance ability of the ankle through three conditions (before floss band intervention, after floss band intervention, and after active exercise intervention) for adults. Methods: One intervention between floss band and active exercise was applied randomly and another intervention was applied the next day. After each intervention, the ROM of the ankle joints and the static balance was checked by measuring conducting one leg test. And the dynamic balance was checked by conducting a Y-balance test. Results: In the case of DF, the range of joint motion showed a significant increase after floss band intervention compared to before floss band intervention (p < 0.05). Static balance ability showed a significant increase after the intervention of floss band and active exercise compared to before the intervention of floss band (p < 0.05). The dynamic balance ability showed a significant increase after the intervention of the floss band compared to before intervention of the floss band and after active exercise intervention (p < 0.05). Conclusion: Based on these results, it was confirmed that the application of floss band to the ankle joint increases DF and improves the static and dynamic balance ability. Based on this fact, we propose the application of a floss band as an intervention method to improve the ROM of the ankle joint and improve the stability of the ankle in clinical field.

The Effect of the Discontinuity Spacing/Length Ratio on Step-Path Failure of Jointed Rock Slopes (절리 암반 사면의 계단 경로 파괴에 미치는 불연속면 간격/길이 비의 영향)

  • Woon Sang Yoon
    • The Journal of Engineering Geology
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    • v.34 no.2
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    • pp.317-327
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    • 2024
  • When a non-persistent joint system is formed in a large-scale rock slope, slope failure may occur due to presence of a the stepped sliding surface. Such a surface can be divided into joint-to-joint sliding surfaces or joint-to-rock bridge sliding surfaces. In the latter case, the rock bridge provides shear resistance parallel to the joint and tensile resistance perpendicular to the joint. The load of the sliding rock can lead to failure of the rock bridge, thereby connecting the two joints at each ends of the bridge and resulting in step-path failure of the slope. If each rock bridge on a slope has the same length, the tensile strength is lower than the shear strength, resulting in the rock bridges oriented perpendicular to the joint being more prone to failure. In addition, the smaller the ratio of discontinuity spacing to length, the greater the likelihood of step-path failure. To assess the risk of stepped sliding on a rock slope with non-persistent joints, stability analysis can be performed using limit equilibrium analysis or numerical analysis. This involves constructing a step-path failure surface through a systematic discontinuity survey and analysis.

Effect of hydraulic distribution on the stability of a plane slide rock slope under the nonlinear Barton-Bandis failure criterion

  • Zhao, Lian-Heng;Cao, Jingyuan;Zhang, Yingbin;Luo, Qiang
    • Geomechanics and Engineering
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    • v.8 no.3
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    • pp.391-414
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    • 2015
  • In this paper, stabilities of a plane slide rock slope under different hydraulic distributions were studied based on the nonlinear Barton-Bandis (B-B) failure criterion. The influence of various parameters on the stability of rock slopes was analyzed. Parametric analysis indicated that studying the factor of safety (FS) of planar slide rock slopes using the B-B failure criterion is both simple and effective and that the effects of the basic friction angle of the joint (${\varphi}_b$), the joint roughness coefficient (JRC), and the joint compressive strength (JCS) on the FS of a planar slide rock slope are significant. Qualitatively, the influence of the JCS on the FS of a slope is small, whereas the influences of the ${\varphi}_b$ and the JRC are significant. The FS of the rock slope decreases as the water in a tension crack becomes deeper. This trend is more significant when the flow outlet is blocked, a situation that is particularly prevalent in regions with permafrost or seasonal frozen soil. Finally, the work is extended to study the reliability of the slope against plane failure according to the uncertainty from physical and mechanics parameters.

The Studies on the Foot Stability and Kinesiology by Direction of Carry a Load during Gait (보행 시 부하의 위치에 따른 발의 안정성 및 운동학적 분석에 관한 연구)

  • Lee, Sang-Yeol;Bae, Sung-Soo
    • The Journal of Korean Physical Therapy
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    • v.21 no.2
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    • pp.97-101
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    • 2009
  • Purpose: This study examined how the direction of carrying a load affects the foot stability and kinesiology while walking. Methods: The heel rotation, Hallux stiffness, foot balance, metatarsal load, toe out angle, subtalar joint flexibility were measured in 40 adults (men and women) who carried a load back and forth, walking on a 2-meter-long board. The measurement was carried out three times and the mean of the measurements was used to compare the difference between the front, back and the condition without a load. Results: While walking, heel rotation and hallux stiffness occurred most when a front load was applied compared to a back load or no load condition (p<0.05). A metatarsal load also appeared to be the highest with the frond load, but there was no significant difference in the balance of the whole foot. Both the toe out angle and subtalar joint flexibility appeared to increase significantly (p<0.05). Conclusion: Applying the front load causes subtalar joint instability and increases the plantar foot pressure imbalance during walking.

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The Effects of Lower Limb Training Using Sliding Rehabilitation Machine on the Foot Motion and Stability in Stroke Patients

  • Lee, Kwan-Sub;Kim, Kyoung;Lee, Na-Kyung
    • The Journal of Korean Physical Therapy
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    • v.27 no.1
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    • pp.24-29
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    • 2015
  • Purpose: The purpose of this study was to investigate the effect of lower limb training using a sliding rehabilitation machine on the foot motion and stability in stroke patients. Methods: Thirty participants were allocated to two groups: Training group (n=15) and Control group (n=15). Subjects in the control group received physical therapy for 30 minutes, five times per week, and those in the training group received lower limb training using a sliding rehabilitation machine for 30 minutes, five times per week, with physical therapy for 30 minutes, five times per week, during a period of six weeks. Heel rotation, hallux stiffness, foot balance, metatarsal load, toe out angle, and subtalar joint flexibility were measured by RS-scan. Results: Significant improvement of the foot motion (hallux stiffness, meta load) and the foot stability (toe out angle, subtalar joint flexibility) was observed in the training group. Conclusion: This study demonstrated that lower limb training using a sliding rehabilitation machine is an effective intervention to improve the foot motion and stability.

Stability and Deformation Analysis Considering Discontinuities in Rock Mass (불연속면을 고려한 암반의 안정변형해석)

  • Hwang, Jae-Yun
    • Tunnel and Underground Space
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    • v.25 no.1
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    • pp.68-75
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    • 2015
  • Rock mass includes such discontinuities as fault, joint, bedding, crack, schistosity, cleavage. The rock mass behavior, therefore, is influenced by the discontinuity behavior. In this study, a stability and deformation analysis method considering discontinuities in rock mass is proposed, and then applied to the rock collapse disaster site. As the method, the stability analysis by the stereographic projection method was carried out in an actual site, the deformation analysis program by the finite element method including the joint element was developed, and performed. To demonstrate the applicability of this developed stability and deformation analysis method considering discontinuities in rock mass, the analysis results are examined and compared with the failure behavior at the rock mass.

Evaluation of Dynamic Behavior of Rail Joints on Personal Rapid Transit Track (소형무인경전철(PRT)궤도 레일이음매의 동적거동 분석)

  • Choi, Jung-Youl;Kim, Jun-Hyung
    • Journal of the Korean Society of Safety
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    • v.31 no.5
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    • pp.89-94
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    • 2016
  • The objective of this study was to estimate the dynamic behavior of a personal rapid transit(PRT) track system using a rail of rectangular tube section and a rail joint of sliding type, and to compare the results with the normal rail and rail joint of a PRT track system by performing field measurements using actual vehicles running along the service lines. The measured vertical displacement of rail and sleeper, and vertical acceleration of rail for the normal rail and rail joint section were found to be similar, and the rail joint of sliding type satisfied the design specifications of the track impact factor for a conventional railway track. The experimental results showed that the overall dynamic response of the rail joint were found to be similar to or less than that of the normal rail, therefore the rail joint of sliding type for PRT track system was sufficient to ensure a stability and safety of PRT track system.