• Title, Summary, Keyword: laboratory modelling

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Numerical modelling of soil-foundation interaction by a new non-linear macro-element

  • Khebizi, Mourad;Guenfoud, Hamza;Guenfoud, Mohamed
    • Geomechanics and Engineering
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    • v.14 no.4
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    • pp.377-386
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    • 2018
  • This paper focuses on the development of a new non-linear macro-element for the modelling of soil-foundation interaction. Material and geometrical nonlinearities (soil yielding and foundation uplift respectively) are taken into account in the present macro-element to examine the response of shallow foundations under monotonic and cyclic loads. Several applications of soil-foundation systems are studied. The results obtained from these applications are in very favourable agreement with those obtained through other numerical models in the literature.

Finite element modelling of reinforced concrete structures with laboratory verification

  • Cheng, Y.M.
    • Structural Engineering and Mechanics
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    • v.3 no.6
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    • pp.593-609
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    • 1995
  • The presence of reinforcement has a significant influence on the stress-strain behaviour of reinforced concrete structures, expecially when the failure stage of the structures is approached. In the present paper, the constrained and non-constrained zones of concrete due to the presence of reinforcement is developed and the stress-stress-strain behaviour of concrete is enhanced by a reinforcement confinement coefficient, Furthermore, a flexible method for the modelling of reinforcement with arbitrary orientation and not passing the nodes of concrete element is also proposed. Numerical examples and laboratory tests have shown that the coefficient and the modelling technique proposed by the author are satisfactory.

A modelling methodology for robotic workcells through knowledge base

  • Kim, Dae-Won;Ko, Myoung-Sam;Lee, Bum-Hee
    • 제어로봇시스템학회:학술대회논문집
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    • pp.583-588
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    • 1989
  • In this paper, a modelling methodology for a robotic workcell is proposed and compared with the conventional Petri nets model. Also, a method for managing the cell operation is described through the knowledge base. The knowledge bases for state transition and assembly job information are obtained from the state transition map(STM) and the assembly job tree(AJT), respectively. Using the knowledge base, the system structure is discussed in both managing the cell operation and evaluating the various performance. Finally, a simulation algorithm is presented with the simulation results to show the effectiveness of the proposed modelling approach.

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Numerical and laboratory investigations of electrical resistance tomography for environmental monitoring

  • Heinson Tania Dhu Graham
    • Geophysics and Geophysical Exploration
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    • v.7 no.1
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    • pp.33-40
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    • 2004
  • Numerical and laboratory studies have been conducted to test the ability of Electrical Resistance Tomography-a technique used to map the electrical resistivity of the subsurface-to delineate contaminant plumes. Two-dimensional numerical models were created to investigate survey design and resolution. Optimal survey design consisted of both downhole and surface electrode sites. Resolution models revealed that while the bulk fluid flow could be outlined, small-scale fingering effects could not be delineated. Laboratory experiments were conducted in a narrow glass tank to validate theoretical models. A visual comparison of fluid flow with ERT images also showed that, while the bulk fluid flow could be seen in most instances, fine-scale effects were indeterminate.

A practical hybrid modelling approach for the prediction of potential fouling parameters in ultrafiltration membrane water treatment plant

  • Chew, Chun Ming;Aroua, M.K.;Hussain, M.A.
    • Journal of Industrial and Engineering Chemistry
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    • v.45
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    • pp.145-155
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    • 2017
  • In this work, a novel approach combining first principle equation of Darcy's law on cake filtration and artificial neural network (ANN) predictive models were utilized to represent the dead-end ultrafiltration (UF) process. Common on-line data available in most industrial-scale UF membrane water treatment plant such as feed water turbidity, filtration time and transmembrane pressure were used as inputs parameters. An UF pilot plant was set up to carry out these experiments. This hybrid modelling approach consisting of cake filtration and ANN models have shown promising results to predict the specific cake resistance and total suspended solids of the feed water with good accuracy. These two filtration parameters are often considered as indicators for membrane fouling propensity. Sensitivity analysis has indicated strong linear correlation between feed water turbidity and specific cake resistance in the UF process. The hybrid model provides an alternative method to estimate these parameters besides the conventional laboratory analysis. This practical modelling approach will be beneficial to industrial-scale UF membrane water treatment plant operations to predict the fouling propensity of the UF process based on commonly available on-line data and simple laboratory analysis.

Numerical modelling of the pull-out response of inclined hooked steel fibres

  • Georgiadi-Stefanidi, Kyriaki;Panagouli, Olympia;Kapatsina, Alexandra
    • Advances in concrete construction
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    • v.3 no.2
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    • pp.127-143
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    • 2015
  • Steel fibre reinforced concrete (SFRC) is an anisotropic material due to the random orientation of the fibres within the cement matrix. Fibres under different inclination angles provide different strength contribution of a given crack width. For that the pull-out response of inclined fibres is of great importance to understand SFRC behaviour, particularly in the case of fibres with hooked ends, which are the most widely used. The paper focuses on the numerical modelling of the pull-out response of this kind of fibres from high-strength cementitious matrix in order to study the effects of different inclination angles of the fibres to the load-displacement pull-out curves. The pull-out of the fibres is studied by means of accurate three-dimensional finite element models, which take into account the nonlinearities that are present in the physical model, such as the nonlinear bonding between the fibre and the matrix in the early stages of the loading, the unilateral contact between the fibre and the matrix, the friction at the contact areas, the plastification of the steel fibre and the plastification and cracking of the cementitious matrix. The bonding properties of the fibre-matrix interface considered in the numerical model are based on experimental results of pull-out tests on straight fibres.

NUCLEAR ENERGY MATERIALS PREDICTION: APPLICATION OF THE MULTI-SCALE MODELLING PARADIGM

  • Samaras, Maria;Victoria, Maximo;Hoffelner, Wolfgang
    • Nuclear Engineering and Technology
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    • v.41 no.1
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    • pp.1-10
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    • 2009
  • The safe and reliable performance of fusion and fission plants depends on the choice of suitable materials and an assessment of long-term materials degradation. These materials are degraded by their exposure to extreme conditions; it is necessary, therefore, to address the issue of long-term damage evolution of materials under service exposure in advanced plants. The empirical approach to the study of structural materials and fuels is reaching its limit when used to define and extrapolate new materials, new environments, or new operating conditions due to a lack of knowledge of the basic principles and mechanisms present. Materials designed for future Gen IV systems require significant innovation for the new environments that the materials will be exposed to. Thus, it is a challenge to understand the materials more precisely and to go far beyond the current empirical design methodology. Breakthrough technology is being achieved with the incorporation in design codes of a fundamental understanding of the properties of materials. This paper discusses the multi-scale, multi-code computations and multi-dimensional modelling undertaken to understand the mechanical properties of these materials. Such an approach is envisaged to probe beyond currently possible approaches to become a predictive tool in estimating the mechanical properties and lifetimes of materials.