• Title/Summary/Keyword: wedge function

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Vibration Analysis of Wedge Type Bar by Ritz Method (Ritz법을 이용한 쐐기형 봉의 진동 해석)

  • Park Sok-Chu
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.8
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    • pp.877-882
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    • 2005
  • This paper discusses the lateral vibration of a bar which has its tip free. The uniform bar has a solution by summation of some simple exponential functions But if its shape is not uniform, its solution could be by Bessel's function, or mathematical solution could not be existed. Enen if the solution of Bessel's function exists. as Bessel function is a series function. we must got the solution by numerical method Hereby the author Proposes the ununiform beam solution of the matrix method by Ritz's method. and Proposes a new deflection shape function.

Study on Effect of KWOMAC of a Contact Lateral-Wedged Insole with Strapping in Patients with Varus Deformity Osteoarthritis of the Knee (내반슬 골관절염 환자에 대한 밀착형 외측 쐐기 스트랩 발받침이 한국형 WOMAC에 미치는 영향에 관한 연구)

  • Lee, Sang-Yang;Gong, Won-Tae
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.13 no.1
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    • pp.26-35
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    • 2007
  • The purpose are to demonstrate the pain, stiffness, and physical function by the Korean Western Ontario MacMaster University(KWOMAC) score of the patients with varus deformity osteoarthritis of the knee after treatment period. Twenty outpatients with knee osteoarthritis(OA) were randomized and divided into the control(n=10) and wedge(n=10) groups. The remission scores of the KWOMAC index of severity for knee OA were compared between the groups. The result of repeated two-way ANOVA's revealed that a contact lateral-wedged insole with strapping produced significantly differences in the pain and physical function score between groups after treatment period(P<0.05), but it was not significant differences in the stiffness score between groups(P>0.05). These results suggest that the pain relief and improvement in function reported by patients with osteoarthritis while using lateral-wedged insole with strapping may be achieved by a reduction in external varus moment and medial compartment load.

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Study on fracture characteristics of reinforced concrete wedge splitting tests

  • HU, Shaowei;XU, Aiqing;HU, Xin;YIN, Yangyang
    • Computers and Concrete
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    • v.18 no.3
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    • pp.337-354
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    • 2016
  • To study the influence on fracture properties of reinforced concrete wedge splitting test specimens by the addition of reinforcement, and the restriction of steel bars on crack propagation, 7 groups reinforced concrete specimens of different reinforcement position and 1 group plain concrete specimens with the same size factors were designed and constructed for the tests. Based on the double-K fracture criterion and tests, fracture toughness calculation model which was suitable for reinforced concrete wedge splitting tensile specimens has been obtained. The results show that: the value of initial craking load Pini and unstable fracture load Pun decreases gradually with the distance of reinforcement away from specimens's top. Compared with plain concrete specimens, addition of steel bar can reduce the value of initial fracture toughness KIini, but significantly increase the value of the critical effective crack length ac and unstable fracture toughness KIun. For tensional concrete member, the effect of anti-cracking by reinforcement was mainly acted after cracking, the best function of preventing fracture initiation was when the steel bar was placed in the middle of the crack, and when the reinforcement was across the crack and located away from crack tip, it plays the best role in inhibiting the extension of crack.

Early cicatricial lagophthalmos release with pentagonal wedge resection of the scar, fat redistribution, and full-thickness skin grafting

  • Chung, Chan Min;Tak, Seung Wan;Lim, Hyoseob;Cho, Sang-Hun;Lee, Jong Wook
    • Archives of Craniofacial Surgery
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    • v.21 no.1
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    • pp.49-52
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    • 2020
  • The specialized structure of the upper eyelid ensures complete closure of the eye and eyeball sealing. An upper eyelid injury can cause various symptoms associated with eyeball trauma, not just scar formation or eyelid deformity. In this report, we describe a case of lagophthalmos observed after wound repair in a patient with a crushing injury caused by a grinder. Several surgical techniques are used to treat lagophthalmos or scar contracture. In most cases, a releasing procedure is performed after 6 months of initial repair. However, if the patient has severe symptoms that are not relieved by conservative care, early revision is inevitable. We describe a case of early lagophthalmos successfully resolved with pentagonal wedge resection, fat redistribution, and full-thickness skin grafting. After the revisional surgery, we observed that the patient regained the ability to completely close the injured eyelid, with restoration of function and favorable cosmetic outcomes. Pentagonal wedge resection to release a retracted structure, fat redistribution to prevent readhesion, and full-thickness skin grafting for enough amount of skin to regain upper eyelid function is useful for scar release and lagophthalmos following crushing injuries of the upper eyelid.

Analysis of Moving Boundary Problem Using Extended Moving Least Squares Finite Difference Method (확장된 이동최소제곱 유한차분법을 이용한 이동경계문제의 해석)

  • Yoon, Young-Cheol;Kim, Do-Wan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.4
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    • pp.315-322
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    • 2009
  • This paper presents a novel numerical method based on the extended moving least squares finite difference method(MLS FDM) for solving 1-D Stefan problem. The MLS FDM is employed for easy numerical modelling of the moving boundary and Taylor polynomial is extended using wedge function for accurate capturing of interfacial singularity. Difference equations for the governing equations are constructed by implicit method which makes the numerical method stable. Numerical experiments prove that the extended MLS FDM show high accuracy and efficiency in solving semi-infinite melting, cylindrical solidification problems with moving interfacial boundary.

The Effect of Hedges and the Electrical Characteristics of the Turbo-generator Rotor of SSR Phenomena (차동기 공진현상에서 터어보 발전기 회전자의 전기적 특성과 Wedge 의 영향)

  • Lee, Eun-Hoong;Lee, Min-Myung;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • 1989.07a
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    • pp.28-30
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    • 1989
  • This paper is analyzed the electrical characteristics of the round solid rotor of turbo-generator without damper cage influence the induction generation modes and the torsional interaction modes of the SSR phenomena, and then examines the problem of representing electrical characteristics which is dependent on frequency and different wedge materials. The basic model of turbo-generator used in the field analysis is viewed as 5-regions of different permeability and conductivity characteristics. The analytical method, which is used in this paper is based on solving a boundary value problem involving 3-D fields, and the basic function consists of the 2-D Fourier series.

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A study on practical method to estimate drag of super-cavitating underwater vehicles

  • Choi, Jung-Kyu;Kim, Hyoung-Tae
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.817-832
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    • 2021
  • In this paper, a simple practical method to estimate the drag of Super-Cavitating Underwater Vehicles (SCUV) is proposed that can obtain the drag with only principal dimensions in an initial design stage. SCUV is divided into cavitator, forebody, afterbody, base, and control fin and the drag of each part is estimated. The formulas for the drag coefficient are proposed for the disk and cone type cavitators and wedges used as control fins. The formulas are a function of cavitation number, cone or wedge angle, and Reynolds number. This method can confirm the drag characteristics of SCUV that the drag hump appears according to the coverage of the body by the cavity and the cavitator drag remains only when the entire body is covered by cavity. Applying this method to SCUV of various shapes, it is confirmed that the effects of cavitating and non-cavitating conditions, cavitator and body shape, and speed could be found.

Lateral Vibration Analysis of a Nonuniform Beam by Ritz's Method (Ritz법에 의한 비균일 단면 외팔보의 횡진동 해석)

  • Park, Sok-Chu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.10
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    • pp.946-949
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    • 2007
  • This paper discusses the lateral vibration of a beam with boundary condition of one end fixed and the other end free. The uniform beam has a solution by summation of some simple exponential functions. But if its shape is not uniform, its solution could be by Bessel's function or mathematical solution could not exist. Even if the solution of Bessel's function exists, as Bessel function is a series function, we must get the solution by numerical method. Author had proposed the solution of the matrix method by Ritz's method and a new mode shape function, and had earned the good results for a wedge beam. Hereby a vibration analysis for the tapered beam with circle cross section was executed, and so good results were showed.

Heat Transfer Analysis of Bi-Material Problem with Interfacial Boundary Using Moving Least Squares Finite Difference Method (이동최소제곱 유한차분법을 이용한 계면경계를 갖는 이종재료의 열전달문제 해석)

  • Yoon, Young-Cheol;Kim, Do-Wan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.6
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    • pp.779-787
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    • 2007
  • This paper presents a highly efficient moving least squares finite difference method (MLS FDM) for a heat transfer problem of bi-material with interfacial boundary. The MLS FDM directly discretizes governing differential equations based on a node set without a grid structure. In the method, difference equations are constructed by the Taylor polynomial expanded by moving least squares method. The wedge function is designed on the concept of hyperplane function and is embedded in the derivative approximation formula on the moving least squares sense. Thus interfacial singular behavior like normal derivative jump is naturally modeled and the merit of MLS FDM in fast derivative computation is assured. Numerical experiments for heat transfer problem of bi-material with different heat conductivities show that the developed method achieves high efficiency as well as good accuracy in interface problems.

Numerical Analysis of a Weak Shock Wave Propagating in a Medium Using Lattice Boltzmann Method (LBM)

  • Kang, Ho-Keun;Michihisa Tsutahara;Ro, Ki-Deok;Lee, Young-Ho
    • Journal of Mechanical Science and Technology
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    • v.17 no.12
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    • pp.2034-2041
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    • 2003
  • This study introduced a lattice Boltzmann computational scheme capable of modeling thermo hydrodynamic flows with simpler equilibrium particle distribution function compared with other models. The equilibrium particle distribution function is the local Maxwelian equilibrium function in this model, with all the constants uniquely determined. The characteristics of the proposed model is verified by calculation of the sound speeds, and the shock tube problem. In the lattice Boltzmann method, a thermal fluid or compressible fluid model simulates the reflection of a weak shock wave colliding with a sharp wedge having various angles $\theta$$\sub$w/. Theoretical results using LBM are satisfactory compared with the experimental result or the TVD.