Wyniki wyszukiwania - BazTech

1

The development of multi-scale data management for CityGML-based 3D buildings

Karim Hairi, Rahman Alias Abdul, Azri Suhaibah, Halim Zurairah

Geomatics and Environmental Engineering

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2022

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Vol. 16, no. 1

71--94

EN

The CityGML model is now the norm for smart city or digital twin city development for better planning, management, risk-related modelling and other applications. CityGML comes with five levels of detail (LoD), mainly constructed from point cloud measurements and images of several systems, resulting in a variety of accuracies and detailed models. The LoDs, also known as pre-defined multi-scale models, require large storage-memory-graphic consumption compared to single scale models. Furthermore, these multi-scales have redundancy in geometries, attributes, are costly in terms of time and workload in updating tasks, and are difficult to view in a single viewer. It is essential for data owners to engage with a suitable multi-scale spatial management solution in minimizes the drawbacks of the current implementation. The proper construction, control and management of multi-scale models are needed to encourage and expedite data sharing among data owners, agencies, stakeholders and public users for efficient information retrieval and analyses. This paper discusses the construction of the CityGML model with different LoDs using several datasets. A scale unique ID is introduced to connect all respective LoDs for cross-LoD information queries within a single viewer. The paper also highlights the benefits of intermediate outputs and limitations of the proposed solution, as well as suggestions for the future.

2

Impact of lift-off in 3MA-NDT harmonic analysis signal-via numerical methods and experiment

Amrane Cylia, Mimoune Souri Mohamed, Khene Mohamed Lotfi, Gabi Yasmine, Mohellebi Hassane, Alloui Lotfi, Straß Benjamin, Wolter Bernd

Przegląd Elektrotechniczny

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2021

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R. 97, nr 12

45--50

EN

In this paper, the impact of lift-off on the 3MA minaturized probe head via harmonic analysis method is discussed. The electromagnetic signals are examined using two numerical computational methods; the finite element method (FEM) and the finite volume method (FVM) by taking into account the hysteretic and eddy current behavior of ferromagnetic parts. The investigation is run on bilayer specimen and the result demonstrates the ability and accuracy of both FVM and FEM to reprocduce the experimental signals. Beside this, simulations are carried out for various lift-off in order to evaluate the skin depth and limit of the magnetic NDT technique.

PL

W artykule omówiono wpływ oderwania na głowicę sondy zminaturyzowanej 3MA metodą analizy harmonicznej. Sygnały elektromagnetyczne są badane za pomocą dwóch numerycznych metod obliczeniowych; metoda elementów skończonych (MES) i metoda objętości skończonych (FVM) z uwzględnieniem histerezy i zachowania prądów wirowych elementów ferromagnetycznych. Badanie prowadzone jest na próbce dwuwarstwowej, a wynik wykazuje zdolność i dokładność zarówno FVM, jak i MES do odtworzenia sygnałów doświadczalnych. Oprócz tego przeprowadzane są symulacje dla różnych podniesień w celu oceny głębokości skóry i granic magnetycznej techniki NDT.

3

FEM x DEM modelling of cohesive granular materials: numerical homogenization and multi-scale simulations

Nguyen T. K., Combe G., Caillerie D., Desrues J.

Acta Geophysica

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2014

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Vol. 62, no. 5

1109--1126

EN

The article presents a multi-scale modelling approach of cohesive granular materials, its numerical implementation and its results. At micro-scopic level, Discrete Element Method (DEM) is used to model dense grain spacking. At the macroscopic level, the numerical solution is obtained by a Finite Element Method (FEM). In order to bridge the micro- and macro-scales, the concept of Representative Elementary Volume (REV) is applied, in which the average REV stress and the consistent tangent operators are obtained in each macroscopic integration point as the results of DEM’s simulation. In this way, the numerical constitutive law is determined through the detailed modelling of the microstructure, taking into account the nature of granular materials. We first elaborate the principle of the computation homogenisation (FEMDEM), then demonstrate the features of our multi-scale computation in terms of a biaxial compression test. Macroscopic strain location is observed and discussed.

4

Effective thermal conductivity of porous materials and composites as a function of fundamental structural parameters

Asakuma Y., Yamamoto T.

Computer Assisted Methods in Engineering and Science

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2013

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Vol. 20, no. 2

89--98

EN

We conducted thermal conductivity investigations by homogenization. This method can effectively model structural features such as pores within dispersed particle architectures via a finite element mesh. We investigated the factors that determine the effective thermal conductivity of porous structures and composites, such as the volume ratio of the continuous and dispersed phases, conductivity ratio, Biot number and particle packing model.