• 제목/요약/키워드: rotational deformation

검색결과 188건 처리시간 0.022초

이차 변형을 이용한 캐릭터 동작의 과장 기법 (Exaggerating Character Motions Using Quadratic Deformation)

  • 권지용;이인권
    • 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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    • 제16권5호
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    • pp.611-615
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    • 2010
  • 본 논문은 이차 변형을 이용하여 캐릭터 동작을 만화적으로 과장하는 방법을 소개한다. 기존의 캐릭터 동작 과장 기법이 각 관절의 회전각 운동 곡선을 독립적으로 과장한 것과 달리, 우리는 캐릭터의 전체적인 포즈를 이차 변형으로 모델링하고 이를 과장함으로써 캐릭터 전체의 움직임이 과장되는 효과를 낼 수 있었다. 제시한 방법은 실시간에 빠르게 계산될 수 있으며 관절이 불안정한 방향으로 꺾이는 등의 부작용이 상대적으로 적다.

커넥팅 로드 베어링의 EHL에 관한 수치해석 (A Numerical Analysis of the Elastohydrodynamic Lubrication of Connecting Rod Bearings)

  • 김병직;김경웅
    • Tribology and Lubricants
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    • 제12권3호
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    • pp.63-71
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    • 1996
  • The connecting rod bearing, which is subjected to periodical dynamic loading, is an impoRant component of the reciprocating engine. In the operation of this bearing, significant parameters are the oil film thickness and the film pressure. Peak film pressures of 20-30 MPa are not uncommon. So the elastic deformation of the bearing housing can have a significant effect on the bearing performance. In this study, a numerical analysis of connecting rod bearing is investigated. Elastic deformation of the bearing housing is considered in the analysis. Separate hydrodynamic and structural analysis are coupled through a direct iterative process. It is shown that as the result of the elastic deformation of the bearing housing, the eccentricity ratio is increased, and the minimum value of the minimum film thickness and the maximum value of the maximum film pressure are decreased. The variations of rotational speed and cylinder pressure affect the minimum film thickness and the maximum film pressure variations of the connecting rod bearing.

탄성스프링으로 지지된 곡선형 Timoshenko 보의 면내 자유진동 (In-Plane Vibrations of Curved Timoshenko Beams with Elastic Springs at Both Ends)

  • 오상진;모정만;강희종
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
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    • pp.105-110
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    • 2007
  • The differential equations governing free, in-plane vibrations of circular curved beams with elastic springs at beth ends, including the effects of axial deformation, rotatory inertia and shear defamation. are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies are calculated over a wide range of non-dimensional system parameters, the radial, tangential and rotational spring parameters, the subtended angle, the slenderness ratio and the shear parameter.

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공구 중량조건에 의한 주축변위 특성연구 (A Study on the Main Spindle Deformatin characteristics by the Tool Weight Condition)

  • 김종관
    • 한국생산제조학회지
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    • 제5권4호
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    • pp.121-128
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    • 1996
  • In order to examine spindle deformation characteristics that affects the performance of dynmic cutting acuracy due to tool weight variation in a experimental spindle. thermal deformation value of operrative spindle by the axial displacement and the radial run out was measured according to the rise of spindle temperature through the laps of operation time and the change of rotational speed under the tool weight variation. A qualitative summary is as follows ; 1) The results show that the tool weight affcets the spindle temperature variation in a experimental spindle. 2) Radial run out and axial displacement was measured according to the rise of the spindle temperature and the performance of dynamic cutting accuracy was affected by the tool weight variation. 3) Axial displacement is 1.3 times larger than the radial run out in a experimental spindle conditions. 4) Axial displacement is continuously elongated when the tool weight is repeatly exchanged since the spindle themal deformaion, however, when the same tool weight is used. the displacement is still constant.

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Free vibration of symmetric angle-ply layered conical shell frusta of variable thickness under shear deformation theory

  • Viswanathan, K.K.;Javed, Saira;Aziz, Zainal Abdul
    • Structural Engineering and Mechanics
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    • 제45권2호
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    • pp.259-275
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    • 2013
  • Free vibration of symmetric angle-ply layered conical shell frusta of variable thickness is analyzed under shear deformation theory with different boundary conditions by applying collocation with spline approximation. Linear and exponential variation in thickness of layers are assumed in axial direction. Displacements and rotational functions are approximated by Bickley-type splines of order three and obtained a generalized eigenvalue problem. This problem is solved numerically for an eigenfrequency parameter and an associated eigenvector of spline coefficients. The vibration of three and five-layered conical shells, made up of two different type of materials are considered. Parametric studies are made for analysing the frequencies of the shell with respect to the coefficients of thickness variations, length-to-radius ratio, length-to-thickness ratio and ply angles with different combination of the materials. The results are compared with the available data and new results are presented in terms of tables and graphs.

BLDC 모터의 고무 자석 형상 변형으로 인한 자계 변형 및 불평형 자기력 해석 (Distortion of Magnetic Field and Magnetic Force of a Brushless DC Motor due to Deformed Rubber Magnet)

  • 이창진;장건희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 추계학술대회논문집
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    • pp.834-839
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    • 2007
  • This paper investigates the distortion of magnetic field of a brushless DC (BLDC) motor due to deformed rubber magnet. Global or local deformation of rubber magnet in the BLDC motor is mathematically modeled by using the Fourier series. Distorted magnetic field is calculated by using the finite element method, and unbalanced magnetic force are calculated by using the Maxwell stress tensor. The first harmonic deformation in the global deformation of rubber magnet generates the first harmonic driving frequency of the unbalanced magnetic force, and the rest harmonic deformations of rubber magnet except the harmonic deformation with multiple of common divisor of pole and slot introduces the driving frequencies with multiple of slot number ${\pm}1$ to the unbalanced magnetic force. However, the harmonic deformation with multiple of common divisor of pole and slot does not generate unbalanced magnetic force due to the rotational symmetry. When the rubber magnet is locally deformed, the unbalanced magnetic force has the first harmonic driving frequency and the driving frequencies with multiples of slot number ${\pm}1$.

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Innovative displacement-based beam-column element with shear deformation and imperfection

  • Tang, Yi-Qun;Ding, Yue-Yang;Liu, Yao-Peng;Chan, Siu-Lai;Du, Er-Feng
    • Steel and Composite Structures
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    • 제42권1호
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    • pp.75-90
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    • 2022
  • The pointwise equilibrium polynomial (PEP) element considering local second-order effect has been widely used in direct analysis of many practical engineering structures. However, it was derived according to Euler-Bernoulli beam theory and therefore it cannot consider shear deformation, which may lead to inaccurate prediction for deep beams. In this paper, a novel beam-column element based on Timoshenko beam theory is proposed to overcome the drawback of PEP element. A fifth-order polynomial is adopted for the lateral deflection of the proposed element, while a quadric shear strain field based on equilibrium equation is assumed for transverse shear deformation. Further, an additional quadric function is adopted in this new element to account for member initial geometrical imperfection. In conjunction with a reliable and effective three-dimensional (3D) co-rotational technique, the proposed element can consider both member initial imperfection and transverse shear deformation for second-order direct analysis of frame structures. Some benchmark problems are provided to demonstrate the accuracy and high performance of the proposed element. The significant adverse influence on structural behaviors due to shear deformation and initial imperfection is also discussed.

Free vibration of cross-ply laminated plates based on higher-order shear deformation theory

  • Javed, Saira;Viswanathan, K.K.;Izyan, M.D. Nurul;Aziz, Z.A.;Lee, J.H.
    • Steel and Composite Structures
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    • 제26권4호
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    • pp.473-484
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    • 2018
  • Free vibration of cross-ply laminated plates using a higher-order shear deformation theory is studied. The arbitrary number of layers is oriented in symmetric and anti-symmetric manners. The plate kinematics are based on higher-order shear deformation theory (HSDT) and the vibrational behaviour of multi-layered plates are analysed under simply supported boundary conditions. The differential equations are obtained in terms of displacement and rotational functions by substituting the stress-strain relations and strain-displacement relations in the governing equations and separable method is adopted for these functions to get a set of ordinary differential equations in term of single variable, which are coupled. These displacement and rotational functions are approximated using cubic and quantic splines which results in to the system of algebraic equations with unknown spline coefficients. Incurring the boundary conditions with the algebraic equations, a generalized eigen value problem is obtained. This eigen value problem is solved numerically to find the eigen frequency parameter and associated eigenvectors which are the spline coefficients.The material properties of Kevlar-49/epoxy, Graphite/Epoxy and E-glass epoxy are used to show the parametric effects of the plates aspect ratio, side-to-thickness ratio, stacking sequence, number of lamina and ply orientations on the frequency parameter of the plate. The current results are verified with those results obtained in the previous work and the new results are presented in tables and graphs.

Cell 구조물의 변형특성에 미치는 셀 벽면 마찰의 영향 (The Effect of Wall Friction on Deformation Characteristics of the Cellular Bulkhead)

  • 손대산;장정욱;김경열;김현국;정연인
    • 한국해안·해양공학회논문집
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    • 제22권4호
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    • pp.230-234
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    • 2010
  • 본 연구에서는 기존의 근입비와 재하높이에 따른 모형실험의 결과를 바탕으로 셀 내벽의 마찰을 인위적으로 증감시켜 셀 구조물의 변형특성에 미치는 벽면 마찰의 영향을 알아보고자 하였다. 그 결과는 다음과 같다. 1. 재하높이가 낮아질수록 그리고 근입비가 증가할수록 셀 구조물의 변형특성에 미치는 벽면마찰의 영향은 적게 나타났다. 또한 벽면 마찰이 감소함에 따라 항복하중도 작은 값을 나타내었다. 2. 재하높이가 낮아질수록 그리고 근입비가 커질수록 셀 구조물의 수평이동 변위에 대한 회전성분 변위의 비가 작게 나타났다. 따라서 벽면 마찰의 영향은 회전성분 변위와 밀접한 관련이 있음을 알 수 있었다.

추가변형을 고려한 환원판 결합 원통셸의 자유진동해석 (Free Vibration Analysis of Combined Cylindrical Shells with an Annular Plate Considering Additional Deformations)

  • 정강;김영완
    • 대한기계학회논문집A
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    • 제29권3호
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    • pp.439-446
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    • 2005
  • The theoretical method is developed to investigate the vibration characteristics of the combined cylindrical shells with an annular plate joined to the shell at any arbitrary axial position. The structural rotational coupling between shell and plate is simulated using the rotational artificial spring. For the translational coupling, the continuity conditions for the displacements of shell and plate are used. For the uncoupled annular plate, the transverse motion is considered and the in-plane motions are not. And the additional transverse and in-plane motions of the coupled annular plate by shell deformation are considered in analysis. Theoretical formulations are based on Love's thin shell theory. The frequency equation of the combined shell with an annular plate is derived using the Rayleigh-Ritz approach. The effect of inner-to-outer radius ratio, axial position and thickness of annular plate on vibration characteristics of combined cylindrical shells is studied. To demonstrate the validity of present theoretical method, the finite element analysis is performed.