• Title/Summary/Keyword: K-Joint

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Numerical simulation and experimental investigation of the shear mechanical behaviors of non-persistent joint in new shear test condition

  • Wang, Dandan;Zhang, Guang;Sarfarazi, Vahab;Haeri, Hadi;Naderi, A.A.
    • Computers and Concrete
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    • v.26 no.3
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    • pp.239-255
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    • 2020
  • Experimental and discrete element method were used to investigate the effects of joint number and its angularities on the shear behaviour of joint's bridge area. A new shear test condition was used to model the gypsum cracks under shear loading. Gypsum samples with dimension of 120 mm×100 mm×50 mm were prepared. the length of joints was 2cm. in experimental tests, the joint number is 1, 2 and 3 and its angularities change from 0° to 90° with increment of 45°. Assuming a plane strain condition, special rectangular models are prepared with dimension of 120 mm×100 mm. similar to joints configuration in experimental test, 9 models with different joint number and joint angularities were prepared. This testing show that the failure process is mostly governed by the joint number and joint angularities. The shear strengths of the specimens are related to the fracture pattern and failure mechanism of the discontinuities. The shear behaviour of discontinuities is related to the number of induced tensile cracks which are increased by increasing the rock bridge length. The strength of samples decreases by increasing the joint number and joint angularities. Failure pattern and failure strength are similar in both of the experimental test and numerical simulation.

A Study of Joint Therapy (II) (관절치료에 관한 연구 (II))

  • Bae, Sung-soo;Lee, Myung-hee;Lee, Sang-yeul;Kim, Sang-soo
    • PNF and Movement
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    • v.7 no.4
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    • pp.17-23
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    • 2009
  • Purpose : The objective of this study was conducted to find out treatment of weight bearing joint problems. Method : This is a literature study with books, seminar note and international PNF course books. Result : In joint therapy have to consider that what kind joint mechanics during movement, what kind relation between rotatory component of the force and translatory component of the force, what kind muscles are in the global mobilizer(GM) and local stabilizer(LS). One joint has muscle imbalance between GM and LS. It will make joint surface degenerative change which will make joint pain. Conclusion : Joint therapy is not only joint mobilization but also biomechanics of joint and GM's and LS's role. Total knee of hip joint replacement is not perfect. Before surgery have to be find out problem solving method within the physical medicine.

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Effect of Kinesiotaping and Joint Mobilization on The Metatarsophalangeal Joint Angle and Pain in Hallux Valgus Patients

  • Choi, Jung Hyun;Kim, Nyeon Jun;An, Ho Jung
    • Journal of International Academy of Physical Therapy Research
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    • v.8 no.2
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    • pp.1152-1157
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    • 2017
  • The aim of this study was to observe the effects of kinesiotaping and joint mobilization on the metatarsophalangeal joint angle and pain in hallux valgus patients Twenty-one female hallux valgus patients in their 20s were divided into two groups, a Kinesiotaping group (KT, n=10) and another group with the addition of joint mobilization (KTJM, n=11). After undergoing 6 weeks of intervention, the change in the metatarsophalangeal joint and pain were measured. Metatarsophalangeal joint angle was significantly increased both the KT and the KTMJ group after intervention. In the change of pain, both the KT and KTJM groups on an individual basis also experienced a significant decrease in pain, though comparison between the two groups failed to represent a significant difference. These findings suggest that Kinesiotatping and joint mobilization increased the joint angle and reduced pain.

Interaction of internal forces of interior beam-column joints of reinforced concrete frames under seismic action

  • Zhou, Hua;Zhang, Jiangli
    • Structural Engineering and Mechanics
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    • v.52 no.2
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    • pp.427-443
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    • 2014
  • This paper presents detailed analysis of the internal forces of interior beam-column joints of reinforced concrete (RC) frames under seismic action, identifies critical joint sections, proposes consistent definitions of average joint shear stress and average joint shear strain, derives formulas for calculating average joint shear and joint torque, and reports simplified analysis of the effects of joint shear and torque on the flexural strengths of critical joint sections. Numerical results of internal joint forces and flexural strengths of critical joint sections are presented for a pair of concentric and eccentric interior connections extracted from a seismically designed RC frame. The results indicate that effects of joint shear and torque may reduce the column-to-beam flexural strength ratios to below unity and lead to "joint-yielding mechanism" for seismically designed interior connections. The information presented in this paper aims to provide some new insight into the seismic behavior of interior beam-column joints and form a preliminary basis for analyzing the complicated interaction of internal joint forces.

Effect of Joint Kinetics and Coordination on the Within-Individual Differences in Maximum Vertical Jump (관절 역학과 협응이 최대 수직 점프의 개인내 수행차에 미치는 영향)

  • Kim, Yong-Woon;Seo, Jung-Suk;Han, Dong-Wook
    • Korean Journal of Applied Biomechanics
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    • v.22 no.3
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    • pp.305-314
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    • 2012
  • The purpose of this study was to investigate the effects of joint kinetics and coordination on within-individual differences in maximum vertical jump. 10 male subjects aged 20 to 30 performed six trials in maximum vertical jump and with based on jump height the good(GP) and bad(BP) performances for each subject were compared on joint kinetics of lower extremity and coordination parameters such as joint reverse and relative phase. The results showed that maximum moment, power, and work done of hip joint and maximum moment of ankle joint in GP were significantly higher than that in the BP but no significant differences for the knee joint. We could observe a significant difference in joint reverse timing between both conditions. And also the relative phase on ankle-knee and ankle-hip in GP were significantly lower than that in the BP, which means that in GP joint movements were more in-phase synchronized mode. In conclusion, mechanical outputs of hip and ankle joints had an effect on within-individual differences in vertical jump and the inter-joint coordination and coordination including sequence and timing of joint motion also might be high influential factors on the performances within individual.

Structural Performance Evaluation of Bolt Connection for Half-sphere Joint between PHC Pile and Steel Column (강재기둥-PHC 파일 간 반구형 접합부(HAT Joint)의 볼트 연결에 대한 구조성능평가)

  • Oh, Jintak;Kim, Sang-Bong;Kim, Young-Sik;Ju, Young K.
    • Journal of Korean Association for Spatial Structures
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    • v.15 no.4
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    • pp.65-72
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    • 2015
  • To overcome the weakness of spread foundation in large space structure, the research of precast pile for replace spread foundation have been conducted. The new type of joint between PHC pile and steel column is named HAT Joint(Hollow hAlf-sphere cast-sTeel Joint). It connected PHC Pile by bolt that verification of bolt connection should be accomplished. In this paper, pull-out test and flexural performance for HAT Joint to verifying the bolt connection is explained. As a result, the pull-out and flexural capacities of bolt were checked to use in real structure. Furthermore, the equation of pull-out strength was proposed.