• Title/Summary/Keyword: Radius Ratio

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A Study on the Flexible Disk Deburring Process Arc Zone Parameter Prediction Using Neural Network (신경망을 이용한 유연디스크 디버링가공 아크형상구간 인자예측에 관한 연구)

  • Yoo, Song-Min
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.6
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    • pp.681-689
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    • 2009
  • Disk grinding was often applied to deburring process in order to enhance the final product quality. Inherent chamfering capability of the flexible disk grinding process in the early stage was analyzed with respect to various process parameters including workpiece length, wheel speed, depth of cut and feed. Initial chamfered edge defined as arc zone was characterized with local radius of curvature. Averaged radius and arc zone ratio was well evaluated using neural network system. Additional neural network analysis adding workpiece length showed enhance performance in predicting arc zone ratio and curvature radius with reduced error rate. A process condition design parameter was estimated using remaining input and output parameters with the prediction error rate lower than 2.0% depending on the relevant input parameter combination and neural network structure composition.

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Application of Kelvin's theory for structural assessment of FG rotating cylindrical shell: Vibration control

  • Khadimallah, Mohamed A.;Hussain, Muzamal;Harbaoui, Imene
    • Advances in concrete construction
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    • v.10 no.6
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    • pp.499-507
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    • 2020
  • In current study, utilizing the Kelvin's theory with polynomial, exponential and trigonometric volume fraction laws for functionally graded cylindrical shell vibrations. Effects of different parameters for ratios of length- and height-to-radius and angular speed versus fundamental natural frequencies been determined for two categories of cylindrical shells with clamped-free edge condition. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing length-to-radius ratio. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases. The frequencies are same when the cylinder is stationary. The frequencies increases and decreases on changing the constituent materials. The frequency results are verified with the earlier literature for the applicability of present model.

Numerical analysis of oscillating square cylinder with corner radius

  • Tong, J.F.;Sohn, C.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03a
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    • pp.316-320
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    • 2008
  • In this paper, the near wake of stationary and transversely oscillating square section cylinders with different corner radii are studied by numerical method to investigate the influence of corner radius. Six models R/D=0,0.1,0.2,0.3,0.4,0.5 (R is the corner radius and D is the characteristic dimension of the body) were studied. It was found that the corner radius of square cylinder significantly influences the flow features around the body both in stationary and oscillating conditions. Results indicate that, as R/D ratio increases, the Strouhal number increases and the separation point decrease for the stationary and oscillating cases.

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Numerical analysis of oscillating square cylinder with corner radius

  • Tong, J.F.;Sohn, C.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.10a
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    • pp.316-320
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    • 2008
  • In this paper, the near wake of stationary and transversely oscillating square section cylinders with different corner radii are studied by numerical method to investigate the influence of corner radius. Six models R/D=0,0.1,0.2,0.3,0.4,0.5 (R is the corner radius and D is the characteristic dimension of the body) were studied. It was found that the corner radius of square cylinder significantly influences the flow features around the body both in stationary and oscillating conditions. Results indicate that, as R/D ratio increases, the Strouhal number increases and the separation point decrease for the stationary and oscillating cases.

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Simulating vibration of single-walled carbon nanotube using Rayleigh-Ritz's method

  • Hussain, Muzamal;Naeem, Muhammad Nawaz;Taj, Muhammad;Tounsi, Abdelouahed
    • Advances in nano research
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    • v.8 no.3
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    • pp.215-228
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    • 2020
  • In this paper, a new method based on the Sander theory is developed for SWCNTs to predict the vibrational behavior of length and ratio of thickness-to-radius according to various end conditions. The motion equation for this system is developed using Rayleigh-Ritz's method. The proposed model shows the vibration frequencies of armchair (5, 5), (7, 7), (9, 9), zigzag (12, 0), (14, 0), (19, 0) and chiral (8, 3), (10, 2), (14, 5) under different support conditions namely; SS-SS, C-F, C-C, and C-SS. The solutions of frequency equations have been given for different boundary condition, which have been given in several graphs. Several parameters of nanotubes with characteristic frequencies are given and vary continuously in length and ratio of thickness-to-radius. It has been illustrated that an enhancing the length of SWCNTs results in decreasing of the frequency range. It was demonstrated by increasing of the height-to-radius ratio of CNTs, the fundamental natural frequency would increase. Moreover, effects of length and ratio of height-to-radius with different boundary conditions have been investigated in detail. It was found that the fundamental frequencies of C-F are always lower than that of other conditions, respectively. In addition, the existence of boundary conditions has a significant impact on the vibration of SWCNTs. To generate the fundamental natural frequencies of SWCNTs, computer software MATLAB engaged. The numerical results are validated with existing open text. Since the percentage of error is negligible, the model has been concluded as valid.

Numerical Analysis on Effects of Radius Ratio in a Concentric Annulus with a Rotating Inner Cylinder (내부회전실린더를 가진 동심환형관에서 반경비의 영향에 관한 수치해석적 연구)

  • Bae, Kang-Youl;Kim, Hyoung-Bum;Lee, Sang-Hyuk
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.327-330
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    • 2006
  • This paper represents the numerical analysis on effects of radius ratio in a concentric annulus with a rotating inner cylinder. The numerical model consisted of two cylinder which inner cylinder is rotating and outer cylinder is fix, and the axial direction is used the cyclic condition because of the length for axial direction is assumed infinite. The diameter of inner cylinder is assumed 86.8mm, the numerical parameters are angular velocity and radius ratio. Also, the whole walls of numerical model have no-slip and the working fluid is used water at $20^{\circ}C$. The numerical analysis is assumed the transient state to observe the flow variations by time and the 3-D cylindrical coordinate system. The calculation grid adopted a non-constant grid for dense arrangement near the wall side of cylinder, the standard $k-{\omega}$ high Reynolds number model to consider the effect of turbulence flow and wall, the fully implicit method for time term and the quick scheme for momentum equation. The numerical method is compared with the experimental results by Wereley and Lueptow, and the results are very good agreement. As the results, TVF isn't appeared when Re is small because of the initial flow instability is disappear by effect of the centrifugal force and viscosity. The vortex size is from 0.8 to 1.1 for TVF at various $\eta$, and the traveling distance for wavy vortex have the critical traveling distance for each case.

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Seismic behaviors of ring beams joints of steel tube-reinforced concrete column structure

  • Zhang, Yingying;Pei, Jianing;Huang, Yuan;Lei, Ke;Song, Jie;Zhang, Qilin
    • Steel and Composite Structures
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    • v.27 no.4
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    • pp.417-426
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    • 2018
  • This paper presents the seismic behaviors and restoring force model of ring beam joints of steel tube-reinforced concrete column structure under cyclic loading. First, the main failure mode, ultimate bearing capacity, stiffness degradation and energy dissipation capacity are studied. Then, the effects of concrete grade, steel grade, reinforcement ratio and radius-to-width ratios are discussed. Finally, the restoring force model is proposed. Results show that the ring beam joints of steel tube-reinforced concrete column structure performs good seismic performances. With concrete grade increasing, the ultimate bearing capacity and energy dissipation capacity increase, while the stiffness degradation rates increases slightly. When the radius-width ratio is 2, with reinforcement ratio increasing, the ultimate bearing capacity decreases. However, when the radius-to-width ratios are 3, with reinforcement ratio increasing, the ultimate bearing capacity increases. With radius-to-width ratios increasing, the ultimate bearing capacity decreases slightly and the stiffness degradation rate increases, but the energy dissipation capacity increases slightly.

Numerical and analytical investigation of cyclic behavior of D-Shape yielding damper

  • Kambiz Cheraghi;Mehrzad TahamouliRoudsari;Sasan Kiasat;Kaveh Cheraghi
    • Structural Engineering and Mechanics
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    • v.89 no.4
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    • pp.411-420
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    • 2024
  • The purpose of this research was to investigate the cyclic behavior of the D-shaped dampers (DSD). Similarly, at first, the numerical model was calibrated using the experimental sample. Then, parametric studies were conducted in order to investigate the effect of the radius and thickness of the damper on energy dissipation, effective and elastic stiffness, ultimate strength, and equivalent viscous damping ratio (EVDR). An analytical equation for the elastic stiffness of the DSD was also proposed, which showed good agreement with experimental results. Additionally, approximate equations were introduced to calculate the elastic and effective stiffness, ultimate strength, and energy dissipation. These equations were presented according to the curve fitting technique and based on numerical results. The results indicated that reducing the radius and increasing the thickness led to increased energy dissipation, effective stiffness, and ultimate strength of the damper. On the other hand, increasing the radius and thickness resulted in an increase in EVDR. Moreover, the ratio of effective stiffness to elastic stiffness also played a crucial role in increasing the EVDR. The thickness and radius of the damper were evaluated as the most effective dimensions for reducing energy dissipation and EVDR.

Sectional Flow-rate Control of Boom Sprayer According to the Steering Radius along Winding Rows (붐방제기의 곡선행로 조향반경에 따른 붐의 구간별 유량제어)

  • Kim E.S.;Kim Y.J.;Rhee J.Y.
    • Journal of Biosystems Engineering
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    • v.31 no.3 s.116
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    • pp.146-152
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    • 2006
  • Most upland in Korea have irregular field shapes. Boom sprayers working alone winding row will show considerable differences of spraying amount per unit area between left and right booms. If flow rates of both booms are equal. This phenomenon becomes significant as steering radius of sprayer decreases. This study was performed to seek a method which reduce the difference of the spray amount between left, right and center booms while spraying along curvy rows. A flow rate control method for keeping application rate of each boom section constant was proposed and experimentally proved using a boom sprayer attached to a cultivating tractor. The flow rate control device was composed of 3 ball valves and a rotary angle sensor. The rotary angle sensor showed a symmetric voltage output with respect to steering radius. The spray overlapping was happened in a boom nearby the steering center when steering radius of the sprayer was less than 5.2 m. Flow rates for left, right and center booms were regulated using ball valves based on the steering radius and spraying areas ration of right/left boom. The Maximum spraying area ratio ($S_{LR}$) of left to right boom section was 1:3.6 at the steering radius of 5.2 m. However, The Maximum achieved right and left spraying flow ratio was 1:2.7.

Lubrication Performance Analyses of Spiral Groove Dry Gas Seals - Part II: Detailed Performance Evaluation of Groove Design Parameters (스파이럴 그루브 드라이 가스 시일의 윤활 성능해석 - Part II: 그루브 설계 파라미터의 상세 성능평가)

  • Lee An Sung;Yang Jae-Hun;Choi Dong-Hoon
    • Tribology and Lubricants
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    • v.20 no.2
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    • pp.68-76
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    • 2004
  • Applying a general Galerkin FE lubrication analysis method to spiral groove dry gas seals, this study intends to analyze in detail the effects of groove design parameters, such as a spiral angle, groove width ratio, groove radius ratio, groove depth ratio, and groove taper ratio, on the lubrication performances of an opening force, leakage, axial stiffness and damping, and angular stiffness and damping at low and high rotating speeds: 3,600 and 15,000 nm. Results show that, for the primary design consideration performances such as the opening force and axial and angular stiffnesses, a spiral angle of $25^{\circ}$, a groove width ratio of 0.46, a groove radius ratio of 1.1, a groove depth ratio of 1.0, and a groove taper ratio of 0.0 are preferred. Where the recommended relatively low values of groove depth and taper ratios are to keep the axial and angular dampings positive or higher than 0 particularly at the high rotating speed.