• Title/Summary/Keyword: Joint condition

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The Waveform Control and Blowhole Generation in the Wave Pulse MIG Welding for Galvanized Steel Sheets (아연도금강판에 대한 중첩펄스 MIG 용접에서의 파형제어와 기공 발생 특성)

  • Cho Sang-Myung;Kim Ki-Jung;Lee Byung-Woo
    • Journal of Welding and Joining
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    • v.23 no.1
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    • pp.69-76
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    • 2005
  • Recently, application of arc welding to galvanized carbon steel sheet is on the increasing Ould in the fields of automobile and construction industries. In arc welding process, zinc is evaporated in weld pool, even under the appropriate welding condition and produce blowhole and/or pit. Zinc gas cause instability of arc and increase spatter and fume. This research is purposed to minimize the heat-input and the formation of porosities in the welded joint of the galvanized carbon steel sheet using variable polarity AC wave pulse MIG welding system. An appropriate welding condition which showed low spatter and good bead appearance was acquired by applying the AC pulse MIG welding machine to DC duplicated MIG welding with the solid wire. When oxygen gas was added to shield gas of MIG welding for galvanized steel sheet, arc length was increased and arc stability was improved. In the AC duplicated welding, the loss of galvanized layer was decreased as the amount of heat-input was decreased when the EN ratio was increased under the condition that average welding current was evenly set.

A Study on the Housing Condition and the Residents' Preferences of the Suburban Housing Complexes (단지형 도시근교주거의 현황 및 선호 조사)

  • Song, Bin-Na;Ju, Seo-Ryeung
    • Journal of the Korean housing association
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    • v.18 no.6
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    • pp.83-91
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    • 2007
  • The purpose of this study is to understand the present housing condition of the suburban housing complex, and the residents' preferences to make their living condition better in Yong-in and Yang-pyeong, Pocheon, Kwang-ju and Kimpo in Kyung-Ki province, Korea. Questionnaire survey has been carried out to figure out the current status and residents' preferences of the Suburban housing complexes (hereafter SHC). The study showed the present status and the demands of people for their houses as a result like the below. First, currently the SHCs are managed by a joint control type, and the preferences of the residents' showed the similar way. Because of this status, the SHC planning is supposed to have the self-governing management and community space to support the activity of their community. Second, most SHCs doesn't have many public facility, in contrast, each house has various exteriors. This result shows the residents want more to develop their own houses' exterior than that of the SHC's public facility. Prior to plan the SHC, a program should be considered to give better understanding to residens what is the complexed life and make them choose what they really want to have. Third, the studied SHCs' renovation activities are commonly focussed on the exteriors. This shows the residents' life style is focussed more on the out-door life. The planning for the future SHC is supposed to have the points that could follow up the out-door friendly situations.

Consideration of Failure Type on the Ground Excavation (지하굴착에 따른 붕괴유형에 대한 고찰)

  • Lee, Jung-Jae;Jung, Kyung-Sik;Lee, Chang-No
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.660-670
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    • 2009
  • Neighboring construction becomes mainstream of Ground excavation in downtown area. This causes the displacement, deformation, stress condition, etc of the ground surroundings. Therefore Neighboring construction have an effect on Neighboring structure. All these years a lot of Neighboring construction carried out, and the accumulation of technology also get accomplished. But earth retaining structure collapse happens yet. Types of earth retaining structure collapse are 12. 1. Failure of anchor or strut system, 2. Insufficiency of penetration, 3. H-pile Failure on excessive bending moment, 4. Slope sliding failure, 5. Excessive settlement of the back, 6. Deflection of H-pile, 7. Joint failure of coupled H-pile, 8. Rock failure when H-pile penetration is rock mass, 9. Plane arrangement of support systems are mechanically weak, 10. Boiling, 11. Heaving, 12. Over excavation. But field collapses are difficult for classification according to the type, because collapse process are complex with various types. When we consider the 12 collapse field, insufficient recognition of ground condition is 4 case. Thorough construction management prevents from fault construction. For limitations of soil survey, It is difficult to estimate ground condition exactly. Therefore, it should estimate the safety of earth retaining system, plan for necessary reinforcement, according to measurement and observation continuously.

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Evaluation of Behavior of Jointed Concrete Pavement Considering Temperature Condition in a Tunnel by Finite Element Method (구조해석을 통한 터널내 줄눈 콘크리트 포장의 거동분석)

  • Ryu, Sung Woo;Park, JunYoung;Kim, HyungBae;Lee, Jaehoon;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.18 no.2
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    • pp.19-27
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    • 2016
  • PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

A Study on Mechanical Shearing Process for Tailored Blank Welding (테일러드블랭크 용접을 위한 전단 공정 연구)

  • 유병길;이경돈
    • Journal of Welding and Joining
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    • v.17 no.2
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    • pp.66-75
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    • 1999
  • Weld bead quality in tailored blank(TB) is critically affected by edge preparation of sheets. The edge quality of prepared sheets for TB can be classified into straightness and the cross section quality of sheared plane such as a ratio of shear face, shear plane angle, etc. In order to have a good edg quality for butt-welding sheets, precision shearing will be recommended. In this paper, the feasibility of a conventional mechanical shearing as the edge preparation for tailored blanks is studyied. It reveals that fine shearing may not be the unique solution as it is generally accepted. To obtain the good shearing condition with a conventional mechanical shearing, experiments were carried out using Tahuchi method. The major parameters affecting a sheared contour are the clearance between upper blade and lower blade, and shear angle. The optimal shearing condition yields a very good straightness along the entire length of the cut, which gives a butt joint gap less than 10% of the base material thickness. The good cross section of sheared plane is also achieved in the optimal shearing condition such as a ratio of the shear face above 65%, a cross section's shear plane angle above 85%, little burr, which is providing finally good weld beads.

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The Kinematical Analysis of Straddle Jump to Push up Motion on Sports Aerobics (스포츠 에어로빅스 Straddle Jump to Push up 동작의 운동학적 분석)

  • Kim, Cha-Nam
    • Korean Journal of Applied Biomechanics
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    • v.12 no.2
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    • pp.77-90
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    • 2002
  • This study serves the purpose of understanding about correct jump and landing motion through Kinematical Analysis of Straddle Jump to Push up Motion at target by four elite sports aerobics athletes have more than four years career. And further more that make good assistance for coaches effective guidance through an offer basic data and correct diagnosis, evaluate of motions. It was picture-taked by two-video camera for Straddle Jump to Push up Motions. Camera speeds are 60 frame/sec. There are Kinematical Variation elements for analysis, the displacement of COG, each angle displacement left/right of shoulder-joint, each angle displacement left/right of knee-joint and each speed left/right of tip of the toes. Every each person accomplished severaly 3 times and we have acquired this conclusion. The conclusions were as follows; 1. Each situation for displacement of COG showed low height of COG by phase 1, 4, 5(79.05${\pm}9.07,\;46.41{\pm}3.65,\;18.66{\pm}0.54cm$) and It showed high height of COG by phase 2, 3($120.80{\pm}6.13,\;148.12{\pm}9.19cm$). 2. Each displacement left, right of shoulder-joint flexion by phase 1($91.07{\pm}8.30,\;90.77{\pm}5.72$deg/sec)and It showed maximal extension angles by phase 2($102.48{\pm}10.00,\;102.39{\pm}10.51$deg/sec). in part of phase 3, left of shoulder-joint angle($94.43{\pm}4.12$deg/sec) showed flexion phase 1, the other right shoulder-joint angle(88.38${\pm}$4.98deg/sec) showed more a little lower than phase 1, in last phase that showed most low by phase 4($70.58{\pm}13.72,\;54.24{\pm}11.58$deg/sec). 3. Each displacement left, right of hip joint showed maximal extent conditions by phase 2, 3($160.35{\pm}22.68,\;1534.77{\pm}5.40$deg/sec, $150.04{\pm}12.79,\;145.54{\pm}13.00$deg/sec) beside, ankle-joint showed minimal angle by phase 1, 4($93.59{\pm}18.92,\;85.37{\pm}13.23$deg/sec, $66.60{\pm}15.77,\;80.60{\pm}16.57$deg/sec). 4. Each displacement left, right of hip joint showed maximal extent conditions by phase 2($157.15{\pm}9.13,\;163.52{\pm}8.18$deg/sec), and right of hip joint showed minimal angle by phase 3($110.87{\pm}13.81,\;77.53{\pm}8.95$deg/sec) It showed alike condition of low angle by phase 1, 4($91.04{\pm}2.31,\;96.26{\pm}2.20$deg/sec). 5. Each displacement left, right of knee-joint showed maximal extent conditions by phase 1, 3, 4($173.46{\pm}2.95,\;171.51{\pm}5.44$deg/sec, $172.24{\pm}4.49,\;171.26{\pm}0.65$deg/sec, $162.78{\pm}2.13,\;164.10{\pm}5.97$deg/sec) but It showed flexion only left of knee-joint by phase 2($164.45{\pm}7.51,\;159.38{\pm}3.48$deg/sec). 6. Each speed left, right of the tip of the toes showed most fastest when someone jumped with lift up leges by phase 1, 2($321.32{\pm}67.91,\;316.90{\pm}41.97$cm/sec, $410.06{\pm}153.06,\;399.77{\pm}189.34$cm/sec), It showed more less speed than phase 1,2 by phase 3($169.74{\pm}67.17,\;150.00{\pm}63.80$cm/sec) and It showed most slow speed than phase 1,2,3 by phase 4($87.22{\pm}34.90,\;85.72{\pm}52.23$cm/sec).

Effect of joint mobilization on improvement of knee pain, isokinetic strength, muscle tone, muscle stiffness in an elite volleyball player with knee injury (무릎손상 엘리트 배구선수에 관절가동운동이 무릎통증, 등속성 근력, 근긴장도, 근경직 개선에 미치는 효과)

  • Wang, Joong-San;An, Ho-Jung;Kim, Yong-Youn
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.326-333
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    • 2016
  • This case study identified the effects of joint mobilization on knee pain, isokinetic strength, muscle tone, and muscle stiffness in an elite volleyball player with a knee injury. The subject had experienced cartilage defects of the left knee joint and underwent surgery to correct the condition. The patient complained of continuous pain in the left knee joint in daily life in addition to pain during exercise. The study was conducted from August 5 to 12, 2015 and joint mobilization was applied to the left knee joint for 15 minutes once a day for 8 days. Knee pain was measured using a visual analogue scale, and the concentric peak torque of the quadriceps and hamstring muscles was measured using an isokinetic muscular strength measurement device. The muscle tone and stiffness of the rectus femoris muscle, vastus medialis, and vastus lateralis on the injured side were measured using a myotonometer. All the measurements were conducted before and after the intervention. Joint mobilization was effective in reducing knee pain on the injured side, increasing the concentric peak torque of the quadriceps and hamstring muscles on both sides, and increasing the muscle stiffness of the quadriceps muscle on the injured side. Concentric peak torque of the quadriceps muscle on the injured side increased a great deal as the number of joint mobilizations was increased, largely diminishing the difference in concentric peak torque between the normal side and injured side. On the other hand, joint mobilization was ineffective in improving the hamstring to quadriceps strength ratio on the injured side. While this study suggests that joint mobilization can be an effective intervention to improve the knee pain, isokinetic strength, and muscle stiffness of elite volleyball players, it should be performed alongside training for an appropriate strength ratio.

Utilization of Induced Polarization and Electrical Resistivity for Identifying Rock Condition (유도분극 전하 충전성과 전기비저항을 활용한 암반 상태 파악 가능성 연구)

  • Park, Jinho;Ryu, Jinwoo;Jung, Jeehee;Lee, In-Mo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.3
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    • pp.493-502
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    • 2016
  • This study examines how rock condition affects the variation of the chargeability and electrical resistivity of the rock. In the theoretical study, the relationship correlating chargeability with the variables affecting it is derived. A parametric study utilizing the derived relationship reveals that the size of narrow pores ($r_1$) is the most influential factor on chargeability, and the salinity of pore water ($C_0$) is the second. In the laboratory experiments, small scale rock fracturing zone is modelled using sand stone. Chargeability and resistivity are measured by changing the size of the joint aperture, the location of fractured zone and the existence of clay gouge and/or clay layer which shows lower chargeability than the sand stone layer in the multi-layered ground. Test results show that chargeability is controlled not by the rock fracturing condition but by the size of narrow pore ($r_1$) where each line of current flow passes through. Also, the chargeability decreases with increase of the pore water salinity ($C_0$). In conclusion, the ground condition can be identified more efficiently by measuring the induced polarization along with the electrical resistivity; identifying the existence of sea water, the layered ground and/or the fractured rock becomes more reliable.

Long-term Follow-up Study of Sternocostoclavicular Hyperostosis (흉골늑골 쇄골간 과골증의 장기추시결과)

  • Kim, Jeung-Il;Suh, Keun-Tak
    • The Journal of the Korean bone and joint tumor society
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    • v.12 no.2
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    • pp.103-111
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    • 2006
  • Purpose: Sternocostoclavicular hyperostosis (SCCH) is a disease of unknown etiology, which is characterized by periosteal reaction and endosteal hyperossification of the sternum, clavicles and upper ribs as well as ossification of the surrounding soft tissue. SCCH is a well recognized but uncommon condition which is important differential diagnosis to consider to avoid misdiagnosis and to differentiate the condition from malignant process. But few studies have reported long-term clinical result of SCCH. We report long-term clinical result of SCCH. Materials and Methods: From 1986 to 2000, 17 cases of SCCH were followed up over two to 14 years. We evaluated the radiologic, pathologic and clinical results. Results: Four men and thirteen women were studied. The age when first symptom appeared were raged from17 to 60(average-48.7) There are no specific bacteriological, serological or histological finding. Usually a permanent increase in the erythrocyte sedimentation rate is found. The radiological examination showed the signs of proliferate destructive arthritis in most case. The majority of patients respond to NSAIDs and antibiotics. Conclusion: Sternocostoclavicular hyperostosis is uncommon benign condition, but important condition in the differential diagnosis of inflammatory or malignant process of this joint.

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Effect of Rock Discontinuities on Dynamic Shear Stress Wave (암반 불연속면이 동적 전단응력파에 미치는 영향)

  • Son, Moorak
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.12
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    • pp.25-32
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    • 2018
  • This paper investigates the effect of rock discontinuities on a shear stress wave that is induced by earthquake or blasting and provides the result of numerical parametric studies. The numerical tests of different conditions of rock and discontinuity have been carried out after confirming that the numerical approach is valid throughout a verification analysis from which the test results were compared with a theoretical solution. In-situ stress condition was considered as a rock condition and internal friction angle and cohesive value, which are the shear strength parameters, were considered as discontinuities condition. The joint inclination angle was also taken into account as a parameter. With the various conditions of different parameters, the test results showed that a shear stress wave propagating through a mass is highly influenced by the shear strength of discontinuities and the condition of joint inclination angle as well as in-situ stress. The study results indicate that when earthquake or blasting-induced dynamic loading propagates through a jointed rock mass or a stratified soil ground the effect of in-situ stress and discontinuities including a stratum boundary should be taken into account when evaluating the dynamic effect on nearby facilities and structures.