• Title/Summary/Keyword: Rolling Up

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Rolling from a Supine to a Prone Position (앙와위에서 복와위로 구르기)

  • Kwon Mi-Ji;Park Rae-Joon
    • The Journal of Korean Physical Therapy
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    • v.5 no.1
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    • pp.101-108
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    • 1993
  • Physical therapy for patients with Multiple sclerosis, Parkinson's disease, Spinal cord injury. Osteoporosis, CVA and Cerebral Palsy often includes the evaluating and teaching of rolling movements. Motor abilities such as rolling from a supine to a prone position, moving to sitting. getting up on all fours and ultimately standing up from a supine position. represents progression toward physical independence. Rolling is important functional abilities for need to dressing, decubit prevent. bed mobility, neck control, crawling, creeping, sitting, standing and walking. The purposes of this study were to describe motor development concept and rolling task patterns and to approach the therapeutic exercises.

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Immediate Effects of Myofascial Release Using Vibration Foam Rolling Methods on Hamstrings Range of Motion, Flexibility, Pressure Pain Thresholds and Dynamic Balance

  • Kim, Ho;Shin, Wonseob
    • Journal of International Academy of Physical Therapy Research
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    • v.11 no.2
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    • pp.2042-2051
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    • 2020
  • Background: Many trials have been conducted the methods and types of intervention of form rollers, but no research has been done yet that mixes the methods and types of intervention. Objectives: To analyze the effects of myofascial release on the improvement of range of motion (ROM), flexibility, pain pressure threshold, and balance. Design: Randomized controlled trial. Methods: All subjects measured ROM, flexibility, pressure pain threshold, and dynamic balance by pre-test. After pre-test, subjects were randomized that static-vibration foam rolling group (n=12), dynamic-vibration foam rolling group (n=12), general foam rolling group (n=12). For the intervention, 3 sets of 90 seconds were applied to each group, and rest time was set to 60 seconds between sets. In the post-test and follow-up test after 10 minutes, all three groups were measured the ROM, flexibility, pressure pain threshold, and dynamic balance. Results: The results of comparing ROM, flexibility, pressure pain thresholds, dynamic balance ability appeared higher significant difference in the pre-post-10 minutes follow up test in comparison between time in the intragroup (P<.001). As a result of comparing the change of pre-post-10 minutes follow up, static vibration foam rolling showed higher significant difference compared to control groups (P<.001). Conclusion: Through this study, when foam rolling is applied within the same intervention time, static foam rolling can be expected to have a better effect than the existing dynamic foam rolling as well as vibration foam roller can expect better effect than general foam rolling.

A Study on the Wear Characteristics of Austempered Ductile Iron (오스템퍼링한 구상흑연주철의 마모특성에 미치는 기지조직의 영향에 관한 연구)

  • Kim, Yun-Bog;Kim, Chang-Gyu;Choi, Chang-Ock
    • Journal of Korea Foundry Society
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    • v.10 no.3
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    • pp.235-246
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    • 1990
  • This study has been carried out to investigate into the rolling wear characteristics of austempered ductile iron under unlubricated dry rolling condition by Amsler type test with 9.09% sliding ratio. Wear amount is increased with increasing of ferrite and retained austenite and it has been found that the amount of rolling wear is decreased when the hardness of matrix are higher. The rolling life up to generation of abnormal condition is conspicusly increased and amount of rolling wear is increased asrolling revolutionis increased and wear of austempered ductile ironunder dry rolling condition. Matrix has been obtained to upper bainite, low bainite at heat treatment, obtained to bull`s eye structure at as cast. It has been found that the amount of rolling wear is decreased when the tensile strength of the casting are increased and then the rolling life up to generation of abnormal wear in conspicuously increased and amount of wear was intend to graphite content.

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Roll Groover Design and Roll Speed Set-up in Bar Rolling Process Design using Rigid-thermo-viscoplastic FEM (강열점소성 유한요소법을 적용한 봉형상압연 공정설계에서의 공형 설계 및 롤속도 설정)

  • 권혁철;김수영;임용택
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.08a
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    • pp.88-97
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    • 1999
  • In this study, a systematic approach for roll pass design in bar rolling was studied. To minimize the trial and errors in the process design, a roll CAD system and a FE analysis system were combined. Based on the system, a methodology for roll pass design by FEM was studied. At first, designed process was compared with the FE analysis results and process redesign based on the FEM results was performed to obtain the specified final geometry. Then, empirical formula for roll speed set-up was compared with the FE analysis results. Further study on various simulations for bar rolling will help in making up for the inaccuracy in the currently used empirical roll speed rules. In addition, verification of the accuracy of the FE analysis system must be performed using experimental data in the industry.

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Study on the Wear Characteristics of Gray Cast Iron under Dry Rolling Condition (건식조건하(乾式條件下)에서 회주철(灰鑄鐵)의 로링마모(磨耗)에 관(關)한 연구(硏究))

  • Choi, Chang-Ock;Kim, Dong-Yun
    • Journal of Korea Foundry Society
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    • v.3 no.2
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    • pp.92-99
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    • 1983
  • This study has been carried out to investigate into the difference of rolling life and rolling wear characteristics for various gray cast iron under unlubricated dry rolling condition by amsler type wear test with 9.09% sliding.The results obtained from this study are summerized as follows: 1) It has been found that the amount of rolling wear id decreased when tensile strength and hardness are low, and then the rolling life up to generation of abnormal wear is conspicuously increased. 2) At the given condition the amount of rolling wear has been found to decrease as carbon equivalent of gray cast iron increases and resistance of crack propagation is an important factor on improvement of wear characteristics. 3) The amount of rolling wear is increased with increasing rolling revolution and wear of gray cast iron under dry rolling condition is characterized by three modes; initial wear, stationary wear and abnormal wear. 4) It has been found that the amount of rolling wear is increased with increasing maximum compressive stress and extremely increased when maximum compressive stress is over 59.1kg.f/mm.

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Deformation Behavior & Rolling Effect on the Hot Rolling of High Nitrogen Stainless Steel (고질소강의 열간압연시 변형거동 및 압연효과)

  • Kim, Y.D.;Kim, D.K.;Lee, J.W.;Bae, W.B.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.329-332
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    • 2008
  • Nowadays, It is required human body-friendly, good mechanical properties, and economical efficiency material, simultaneously. The material to meet above requirement condition rear up high nitrogen stainless steel(HNS). However, HNS have a lot of problem such as poor workability, hot crack sensitivity. So, It is needed the condition of plastic working to overcome above many problem. In this study, VIM ingot with 100kg was made by pressurized vacuum induction melting. And then, The slab perform for hot rolling was prepared by open-die forging. Hot rolling process was performed by computer simulation according to change of height reduction, rolling temperature, heating numbers, rolling pass and so forth. The results of analysis were investigated between analysis and lab-scale rolling product.

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Simulation of H-beam rolling process using FEM (FEM을 이용한 H형강 압연공정 해석)

  • Park, C.S.;Kim, J.M.;Woo, K.M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.419-422
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    • 2008
  • It is most important to design the roll pass in shape rolling process. However, roll pass design has been accomplished by experience and intuition of a skilled engineer up to now. And it has being produced throughout a lot of trial and error. Thus, in this study, we tried to analysis the rolling process of H-beam by using FEM program for the quantitative evaluation of the plastic deformation. It could be predicted that rolling load, torque, shape of cross section and distribution of effective strain each pass by the analysis of rolling from break down mill(2 Hi rolling) to finishing rolling(Universal rolling) considering the heat transfer.

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Analysis of edge drop and development of numerical formula for edge drop control of cold rolled sheet (냉연판의 엣지드롭 해석 및 제어용 수식모델 개발)

  • Song, Gil-Ho;Park, Hae-Du;Jin, Cheol-Je;Sin, Seong-Gap
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.4
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    • pp.723-730
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    • 1998
  • With the introduction of edge drop control system in Tandem Cold Rolling Mill, it is necessary to develop te numerical expression for the set-up and edge drop automatic control of cold rolled sheet. As a first step we developed a simulation program which predicts profile and the amounts of edge drop at the delivery side of each stand by using roll deformation anlysis with the slit roll model. And by using the program the effect of various rolling conditions on edge drop was investigated. As a result the relations were obtained between the amounts of edge drop and rolling conditions. Based on above relations, the numerical expression was developed for the set-up and automatic control of edge drop by multi-regression of simulation results for the variation of edge drop amount with each rolling condition.

A study on rolling materials and work roll wear in the cold rolling

  • Jeon, Eon-Chan;Kim, Soon-Kyung;Kim, Moon-Kyung
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.4
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    • pp.128-134
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    • 1993
  • Work roll wear in the cold rolling of mild steel strip is strongly affected by rolling materials, rolling conditions and lubrication. The tests were performed to find the effects of rolling materials under the same lubrication conditions. The obtained results are as follfws; 1) The decrease in surface roughness of work roll is more rapid in that case of continuously cast A1-killed steel strip than ingot cast steel strip. In rolling of continuously cast A1-killed steel strip, worn powder rich in A1$\_$2/O$\_$3/sticks to the work roll surface, and so it makes the mirror surface of work roll accelerate. 2) Amount of work roll wear is small in rolling of continuously cast A1-killed strip. 3) In rolling of continously cast A1-killed steel strip, it is necessary to put up the intial surface roughness of work roll in order to prevent work roll slip.

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Effects of Varying Contact back-up Roll on the strip flatness (VCR 롤이 판평판도에 미치는 영향)

  • Chen, Xianlin;Zhang, Jie;Yang, Quan;Zhang, Quingdong
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.03a
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    • pp.144-147
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    • 1998
  • VCR is a back-up roll with a special contour which leads to the length of the contact line between back-up roll and work becones self adjustable in accordance with the width of the strip. The simulation of a finite element model and the on-line test at production mill demonstrate that the VCR roll may keep the crown of the roll gap relatively stable, and at same time, permit the rolling pressure to be adjusted over a wider range, and increase the effect of work roll bending on the roll gap. The VCR rolls have been successfully used at the first stands of two largest cold rolling mills in China, and on-line test has been done at a wide hot strip finishing train. The use of VCR roll has created favorable conditions for subsequent rolling passes and the achievement of better flatness quality.

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