• Title/Summary/Keyword: new model

Search Result 20,004, Processing Time 0.043 seconds

Capillary Hysteresis Model in Unsaturated Flow : State of the Art

  • Park, Chan-Kun;Sonu, Jun-Ho
    • Korean Journal of Hydrosciences
    • /
    • v.4
    • /
    • pp.33-49
    • /
    • 1993
  • The Purpose of this study is to classify existing hysteresis models and to discuss a possibility of a new type of the hysteresis model. The existing hysteresis models are classified into three types: the interpolation model, the scaling model and the domain model, of which only domain model is to simulate hysteresis curves based on the theoretical approach, It is useful to develop a hysteresis model that requires only one branch of hysteresis curves for the model calibration because obtaining hysteresis curves by experiments is expensive and time-concept by many investigators, however their models are not successful to accurately simulate real data of Rubicon Sandy Loam and Dune Sand. There is a possibility that a new model is based on the dependent domain concept considering the weighting factor, $P_a$($\theta$), which accounts for the pore blockage effect against air entry. Conclusively, a new model where the weighting factor $P_a$($\theta$) in Model III-1 (Mualem, 1984) reduces to a known variable through an appropriate method is an alternative model which required only one branch of main curves for the model calibration.

  • PDF

New Free Wake Method Development for Unsteady Aerodynamic Load on HAWT Blade and Experimental Analysis (풍력블레이드 비정상 공력하중 해석을 위한 자유후류기법 개발 및 실험적 연구)

  • Shin Hyungki;Park Jiwoong;Kim Hogeon;Lee Soogab
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.33-36
    • /
    • 2005
  • A critical issue in the field of the rotor aerodynamics is the treatment of the wake. The wake is of primary importance in determining overall aerodynamic behavior, especially, a wind turbine blade includes the unsteady air loads problem. In this study, the wake generated by blades are depicted by a free wake model to analyse unsteady loading on blade and a new free wake model named Finite Vortex Element(FVE hereafter) is devised in order to include a wake-tower interact ion. In this new free wake model, blade-wake-tower interaction is described by cutting a vortex filament when the filament collides with a tower. This FVE model is compared with a conventional free wake model and verified by a comparison with NREL and SNU wind tunnel model. A comparison with NREL and SNU data shows validity and effectiveness of devised FVE free wake model and an efficient.

  • PDF

정면 밀링의 절삭력 해석을 위한 평균 비절삭저항 모델의 개발

  • 이병철;황정철;김희술
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1992.10a
    • /
    • pp.28-33
    • /
    • 1992
  • The paper describes a new mean specific cutting pressure model in order to improve the accuracy of prediction of cutting force for face milling. The new mean specific cutting pressure model produces a mean specific cutting pressure and coefficients applied to existing cutting model not by traditional method but by considering intermittence and variation of chip width according to insert cutting position to take into cutter geometry machining condition and width of workpiece, and considering a mean measure force according to spindle eccentricity and mean measure force according to spindle eccentricity and insert initial position errors.. The simulated forces in X, Y, Z directions resulted from the simulated cutting model and the new cutting model are compared with measured forces in the time end frequency domains. The simulated forces in the time and frequency domains. The simulated forces resulted from the new cutting model have a good degreement with measured forces in comparison with these resulted from the existing cutting model

The high-rate brittle microplane concrete model: Part I: bounding curves and quasi-static fit to material property data

  • Adley, Mark D.;Frank, Andreas O.;Danielson, Kent T.
    • Computers and Concrete
    • /
    • v.9 no.4
    • /
    • pp.293-310
    • /
    • 2012
  • This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.

Experimental Model for Determining Drawbead Forces (드로우비드력 결정을 위한 실험모델)

  • Moon, S.J.;Lee, M.G.;Keum, Y.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.217-219
    • /
    • 2008
  • A new experimental model for determining drawbead forces, which modifies the dieface of Nine's experimental model, is introduced and the better validity of the drawbead opening and restraining forces of new model than those of Nine's is demonstrated. While Nine's model considers a blank holding force as one of forming variables, new model excludes it by removing blank holder in the dieface. The comparison of the strains found by FEM simulation of automotive fender draw forming process with those measured in a formed panel recommends the new model for accurate drawbead forces.

  • PDF

과학기술정책을 위한 국가학습조직모형

  • 오형식;신상문
    • Journal of Technology Innovation
    • /
    • v.5 no.2
    • /
    • pp.22-47
    • /
    • 1997
  • This paper suggests a model of Living & Learning Nation as a new ploicy framework. It is a combination of Living Nation and Learning Nation. Living Nation model takes the nation as a living entity composed of spirit, resource, and communication : it grows but healthy and balanced growth is needed, its organs are closely connected, it has a circulation system, the 'spirit' factor plays the central role, etc.. Learning Nation model is a national level version of learning organization concept. The model defines new perspectives on the objectives, span of means, and the role of government in S&T policy. Therefore, the model can be used to give new insights to policymakers of developing countries facing the knowledge-based economy.

  • PDF

A Configurational Model of Intonation (억양 배형 곡선 모형)

  • Lee Yeong-kil
    • MALSORI
    • /
    • no.11_14
    • /
    • pp.73-89
    • /
    • 1987
  • This paper is an attempt to propose a new model of intonation called 'Configurational Contour Model'. For our purpose two previous models are discussed : one is the system of tonetic-stress marks and the other is the theory of pitch levels. To overcome shortcomings which these approaches display, the new model is based on two fundamental characteristics of intonation: (1) that intonation is a suprasyllabic phenomenon; and (2) that intonation is basically a matter of configurations, i.e., of rising, falling and level. Accordingly, the new model can be relatable to relevant aspects of the phonetic representation of utterances and also can express all the tonal oppositions in a given language.

  • PDF

Development of A New Truss Model for RC Beams without Web Reinforcement (전단보강철근이 없는 RC보의 트러스 해석기법 연구)

  • Kim, Jee-Hoon;Jeong, Jae-Pyong;Kim, Woo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2001.11a
    • /
    • pp.1109-1114
    • /
    • 2001
  • This paper describes an attempt to develop a new truss model for reinforced concrete beams failing in shear based on a rational behavioral model. The key idea incorporated with truss model is the internal force state factor which is able to express global state of internal force flow in cracked reinforced concrete beams subjected to shear and bending. A new truss model using internal force state factor may provide a comprehensive result of shear strength in reinforced concrete beams without web reinforcement.

  • PDF

Existence Condition for the Stationary Ergodic New Laplace Autoregressive Model of order p-NLAR(p)

  • Kim, Won-Kyung;Lynne Billard
    • Journal of the Korean Statistical Society
    • /
    • v.26 no.4
    • /
    • pp.521-530
    • /
    • 1997
  • The new Laplace autoregressive model of order 2-NLAR92) studied by Dewald and Lewis (1985) is extended to the p-th order model-NLAR(p). A necessary and sufficient condition for the existence of an innovation sequence and a stationary ergodic NLAR(p) model is obtained. It is shown that the distribution of the innovation sequence is given by the probabilistic mixture of independent Laplace distributions and a degenrate distribution.

  • PDF

Estimation of ultimate bearing capacity of shallow foundations resting on cohesionless soils using a new hybrid M5'-GP model

  • Khorrami, Rouhollah;Derakhshani, Ali
    • Geomechanics and Engineering
    • /
    • v.19 no.2
    • /
    • pp.127-139
    • /
    • 2019
  • Available methods to determine the ultimate bearing capacity of shallow foundations may not be accurate enough owing to the complicated failure mechanism and diversity of the underlying soils. Accordingly, applying new methods of artificial intelligence can improve the prediction of the ultimate bearing capacity. The M5' model tree and the genetic programming are two robust artificial intelligence methods used for prediction purposes. The model tree is able to categorize the data and present linear models while genetic programming can give nonlinear models. In this study, a combination of these methods, called the M5'-GP approach, is employed to predict the ultimate bearing capacity of the shallow foundations, so that the advantages of both methods are exploited, simultaneously. Factors governing the bearing capacity of the shallow foundations, including width of the foundation (B), embedment depth of the foundation (D), length of the foundation (L), effective unit weight of the soil (${\gamma}$) and internal friction angle of the soil (${\varphi}$) are considered for modeling. To develop the new model, experimental data of large and small-scale tests were collected from the literature. Evaluation of the new model by statistical indices reveals its better performance in contrast to both traditional and recent approaches. Moreover, sensitivity analysis of the proposed model indicates the significance of various predictors. Additionally, it is inferred that the new model compares favorably with different models presented by various researchers based on a comprehensive ranking system.