• 제목/요약/키워드: Chair modeling

검색결과 16건 처리시간 0.023초

나무 성장 시뮬레이션을 이용한 의자 모델링 기법 (Tree-inspired Chair Modeling)

  • ;변혜원
    • 한국컴퓨터그래픽스학회논문지
    • /
    • 제23권5호
    • /
    • pp.29-38
    • /
    • 2017
  • 본 논문은 나뭇가지 패턴을 의자의 골격에 임의로 합성하는(Tree-Inspired Chair) 모델링 기법을 제안한다. 여러 개의 입력모델을 합성하는 기존 기법과 다르게, 제안 기법은 하나의 메쉬만 사용하여, 사용자가 원하는 부분의 contour mesh로부터 나무 성장 시뮬레이션으로 생성된 패턴을 갖는 의자 모델링이 가능하다. 우리는 나뭇가지 패턴을 생성시킬 영역 contour mesh를 효율적으로 추출하기 위하여 새로운 기법을 제안한다. 우선, 입력된 모델의 face 면적에 기반한 contour mesh를 생성하고, 그 메쉬의 앞뒷면 정보를 이용하여 연결정보가 복원된 skeleton mesh를 생성한다. 또한, 입력 모델의 형상과 유사하게 나뭇가지 패턴을 생성하기 위해 형상 표면의 tangent vector를 고려하는 3-way 나무성장 시뮬레이션 기법을 제안한다. 제안기법은 기존의 가구 모델을 이용하여 간단한 파라미터의 조작만으로 나뭇가지 형상과 가구 모델의 골격을 결합하는 새로운 형태의 가구 모델링을 보여준다. 우리는 실험을 통하여 제안 기법의 성능과 유효성을 보여주었다.

작업안전성 향상을 위한 신개념 VDT 작업용 의자의 인간공학적 설계 (Design of a New-Concept VDT Workstation Chair for Improving Work Safety)

  • 신종현;박민용;김정룡
    • 대한산업공학회지
    • /
    • 제25권4호
    • /
    • pp.459-465
    • /
    • 1999
  • A new-concept VDT workstation chair with adjustable keyboard/mouse support was proposed to minimize physical discomfort and the risk of cumulative trauma disorders (CTDs) at work sites in this study. First, a three-dimensional human modeling tool $(SAFEWORK^{(R)})$ was used to design the new chair satisfying the anthropometric specifications of Korean population. Second, based upon the result of 3-D graphical simulation, a mock-up chair was constructed with an adjustable keyboard/mouse support directly attached to the chair body. Third, muscle fatigue and subjective discomfort were measured to evaluate the newly developed chair. An experiment was conducted to compare the new workstation chair to the traditional computer chair without keyboard/mouse support. Six volunteer subjects participated in six one-hour word-processing sessions with two different chairs and three different postures. Statistical results indicate that the new-concept VDT chair generally improved subjective comfort level and reduced fatigue in finger flexor/extensor and low back muscle. In conclusion, this new VDT workstation chair is expected to reduce physical discomfort and prevent occupational CTD problems in the long run. Implications of the new design and suggestions for the further development are also addressed.

  • PDF

다채널 디스플레이에서 X3D와 모션체어를 이용한 수중운동체 시뮬레이터 (An Underwater Simulator Using X3D and a Motion Chair in a Multi-channel Display Room)

  • 허필원;양정삼;한순흥
    • 한국CDE학회논문집
    • /
    • 제13권1호
    • /
    • pp.45-57
    • /
    • 2008
  • A submarine good military weapon because of its confidentiality and intimidating power. Therefore, training warfighters how to maneuver submarine is very important. Because submarine is very expensive and has regional and temporal limitations, M&S(Modeling and Simulation) can be a good alternative. However, as the existing M&S systems of submarine generally use expensive commercial software and dedicated hardware, which cause the warfighters to take troubles to visit the secured places, and then to train themselves during limited time slots. Also, many M&S systems have only one-channel display system which reduces the sense of immersiveness. Another problem is that many heterogeneous simulators can hardly be used as an integrated system. To solve these problems, X3D, a platform-independent and open standard graphic file format, is used with the general-purpose PCs. To increase immersiveness, multi-channel display system and a motion chair are used. Finally, HLA/RTI is used to integrate individual components of the simulator. All of these are verified through experiments.

Improved version of LeMoS hybrid model for ambiguous grid densities

  • Shevchuk, I.;Kornev, N.
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • 제10권3호
    • /
    • pp.270-281
    • /
    • 2018
  • Application of the LeMoS hybrid (LH) URANS/LES method for the wake parameters prediction is considered. The wake fraction coefficient is calculated for inland ship model M1926 under shallow water conditions and compared to results of PIV measurements. It was shown that due to lack of the resolved turbulence at the interface between LES and RANS zones the artificial grid induced separations can occur. In order to overcome this drawback, a shielding function is introduced into LH model. The new version of the model is compared to the original one, RANS $k-{\omega}$ SST and SST-IDDES models. It is demonstrated that the proposed modification is robust and capable of wake prediction with satisfactory accuracy.

Biomechanical Analysis with the Force of Deltoid Muscle for Pianist

  • Shin, Dong-Ok;La, Seung-Houn
    • International Journal of Safety
    • /
    • 제4권1호
    • /
    • pp.27-31
    • /
    • 2005
  • This study presents the relationship between the height of the chair and the force of deltoid muscle for pianist. The subject simulated playing the piano on the three different heights of the chairs. Digital camera was used to determine the angle of the joint of shoulder and elbow for 2-dimensional static link segment modeling in the sagittal plane. The deltoid, biceps and triceps muscles were considered to determine the muscle load. The results, compared to the force of deltoid muscle, are that the downward position of the higher chair produces significantly large force than the other two lower chairs. It can be caused by hunched shoulder with decreasing deltoid angle. In case of the upward position caused by the lower chair, even though the smallest force of deltoid presented, it was increased the force of elbow.

Multiscale finite element method applied to detached-eddy simulation for computational wind engineering

  • Zhang, Yue;Khurram, Rooh A.;Habashi, Wagdi G.
    • Wind and Structures
    • /
    • 제17권1호
    • /
    • pp.1-19
    • /
    • 2013
  • A multiscale finite element method is applied to the Spalart-Allmaras turbulence model based detached-eddy simulation (DES). The multiscale arises from a decomposition of the scalar field into coarse (resolved) and fine (unresolved) scales. It corrects the lack of stability of the standard Galerkin formulation by modeling the scales that cannot be resolved by a given spatial discretization. The stabilization terms appear naturally and the resulting formulation provides effective stabilization in turbulent computations, where reaction-dominated effects strongly influence near-wall predictions. The multiscale DES is applied in the context of high-Reynolds flow over the Commonwealth Advisory Aeronautical Council (CAARC) standard tall building model, for both uniform and turbulent inflows. Time-averaged pressure coefficients on the exterior walls are compared with experiments and it is demonstrated that DES is able to resolve the turbulent features of the flow and accurately predict the surface pressure distributions under atmospheric boundary layer flows.

중국 명왕조 시대의 좌구(坐具, 의자)에 관한 연구 (The research on the chair of the Ming Dynasty in China)

  • 김미옥
    • 한국실내디자인학회논문집
    • /
    • 제32호
    • /
    • pp.90-96
    • /
    • 2002
  • Laying stress on the upper classes of Western Europe until from the seventeenth to the eighteenth century, the chinese mode in the fields of architecture, interior design and fashion was widely liked. It is called as ‘chinoiserie’into the French language. The chinese design with its quantity and ornamentation exerted an influence upon‘Rococo’in France and upon ‘Chippendale’ in England. The chinese mode that was made best use of the furniture design is the one of Ming dynasty. This was developed in relation to the interior design of ‘Siheyuan’ that is the architectural mode in those days. The furnitures at the times of Ming dynasty was raised to the position of the golden era in the history of chinese furnitures. The furniture has the technique laying stress on symmetrical proportion, simplicity. This technique showed as the formative modeling. also on the part of decoration ornamental designs showing the china ideology of Taoism, Buddhism and Confucianism it was used. In this formative modeling the ideological background of those days forms the groundwork. The combination of reason and sentiment and of heart and mind emphasizes that our emotion should be in control by the ration and our emotion and ration should be harmonized.

Long-term simulation of wind turbine structure for distributed loading describing long-term wind loads for preliminary design

  • Ibrahimbegovic, Adnan;Boujelben, Abir
    • Coupled systems mechanics
    • /
    • 제7권2호
    • /
    • pp.233-254
    • /
    • 2018
  • In order to reduce the dependency on fossil fuels, a policy to increase the production capacity of wind turbine is set up. This can be achieved with increasing the dimensions of offshore wind turbine blades. However, this increase in size implies serious problems of stability and durability. Considering the cost of large turbines and financial consequences of their premature failure, it is imperative to carry out numerical simulations over long periods. Here, an energy-conserving time-stepping scheme is proposed in order to ensure the satisfying computation of long-term response. The proposed scheme is implemented for three-dimensional solid based on Biot strain measures, which is used for modeling flexible blades. The simulations are performed at full spatial scale. For reliable design process, the wind loads should be represented as realistically as possible, including the fluid-structure interaction (FSI) dynamic effects on wind turbine blades. However, full-scale 3D FSI simulations for long-term wind loading remain of prohibitive computation cost. Thus, the model to quantify the wind loads proposed here is a simple, but not too simple to be representative for preliminary design studies.

Prediction of seismic cracking capacity of glazing systems

  • O'Brien, William C. Jr.;Memari, Ali M.;Eeri, M.
    • Earthquakes and Structures
    • /
    • 제8권1호
    • /
    • pp.101-132
    • /
    • 2015
  • This research formulates a closed-form equation to predict a glass panel cracking failure drift for several curtain wall and storefront systems. An evaluation of the ASCE 7-10 equation for Dclear, which is the drift corresponding to glass-to-frame contact, shows that the kinematic modeling assumed for formulation of the equation is sound. The equation proposed in this paper builds on the ASCE equation and offers a revision of that equation to predict drift corresponding to cracking failure by considering glazing characteristics such as glass type, glass panel configuration, and system type. The formulation of the proposed equation and corresponding analyses with the ASCE equation is based on compiled experimental data of twenty-two different glass systems configurations tested over the past decade. A final comparative analysis between the ASCE equation and the proposed equation shows that the latter can predict the drift corresponding to glass cracking failure more accurately.

Nonlinear rheology of linear polymer melts: Modeling chain stretch by interchain tube pressure and Rouse time

  • Wagner, Manfred H.;Rolon-Garrido, Victor H.
    • Korea-Australia Rheology Journal
    • /
    • 제21권4호
    • /
    • pp.203-211
    • /
    • 2009
  • In flows with deformation rates larger than the inverse Rouse time of the polymer chain, chains are stretched and their confining tubes become increasingly anisotropic. The pressures exerted by a polymer chain on the walls of an anisotropic confinement are anisotropic and limit chain stretch. In the Molecular Stress Function (MSF) model, chain stretch is balanced by an interchain pressure term, which is inverse proportional to the $3^{rd}$ power of the tube diameter and is characterized by a tube diameter relaxation time. We show that the tube diameter relaxation time is equal to 3 times the Rouse time in the limit of small chain stretch. At larger deformations, we argue that chain stretch is balanced by two restoring tensions with weights of 1/3 in the longitudinal direction of the tube (due to a linear spring force) and 2/3 in the lateral direction (due to the nonlinear interchain pressure), both of which are characterized by the Rouse time. This approach is shown to be in quantitative agreement with transient and steady-state elongational viscosity data of two monodisperse polystyrene melts without using any nonlinear parameter, i.e. solely based on the linear-viscoelastic characterization of the melts. The same approach is extended to model experimental data of four styrene-butadiene random copolymer melts in shear flow. Thus for monodisperse linear polymer melts, for the first time a constitutive equation is presented which allows quantitative modeling of nonlinear extension and shear rheology on the basis of linear-viscoelastic data alone.