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Examples of the aggregates analysed

Examples of the aggregates analysed

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Article
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An algorithm to re-create virtual aggregates with realistic shapes is presented in this paper. The algorithm has been implemented in the Unity 3D platform. The idea is to re-create realistically the virtual coarse and crushed aggregates that are normally used as a material for the construction of roads. This method consists of two major procedures:...

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... In previous studies, several preprocessing methods similar to scale decomposition have been used, such as spherical harmonic reconstruction [10], the marching cube method [53], and the mesh-resolution adjustment method [3]. As mentioned previously, spherical harmonic Fig. 9 Typical microscope images of lunar and terrestrial soil particles [22] Acta Geotechnica reconstruction means approaching nonstationary signals with stationary signal tools, which necessitates high computational costs to improve accuracy (see Appendix A). ...
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Particle morphology is a fundamental property of granular geomaterials such as rock and soil. A reasonable characterization of irregular particle morphology is of great significance on determining materials’ physical, mechanical and hydraulic behaviors. The purpose of this study is to establish a generic theory for the morphology characterization of irregular particles. First, the Hilbert–Huang transform (HHT) of the field of nonstationary signal processing is introduced into the morphology analysis, and then the complex morphology of irregular particles is decomposed into a series of analysis objects of different scales based on HHT. Then, for the first time, according to geometric measure theory, a comprehensive descriptor system of morphology characterization with clear physical meaning is rigorously established step by step starting from basic mathematical concepts such as set and measure, in which most existing morphology descriptors can be unified, and some new valuable descriptors are extracted. The scale decomposition and descriptor system comprise the complete and generic morphology characterization of irregular particles. At the same time, a highly efficient computation program including the scale decomposition and descriptor calculation of the characterization is provided as a free download. Particle morphology analyses of lunar soil simulants and common river sand are illustrated to validate the effectiveness of the proposed characterization. Because of their generality, except for irregular particles, the characterization and corresponding program have the potential to be applied to any irregular geometry.
... The first step to manufacture virtual particulate materials is to create virtual aggregates. To do so, the shape of particles can be recorded, which can be done by using different acquisition systems as 3D laser scanner, X-ray Computed Tomography, or image acquisition systems, as can be seen in [11] and [12] and [13] respectively. Then, we need to recreate these shapes computationally. ...
... Eleven types of coarse aggregates from different sources and different shape characteristics have been used in this study. These aggregates had been characterised in detail in reference [13], where they have been also classified based on their circularity and sphericity, using the Krumbein chart used for visual evaluation of aggregates. The particles are glass spheres (GS); crushed glass (CG); round gravel (RG); slag (S); five types of Limestone: L1, L2, L3, L4 and L5, with maximum size 20 mm, 6 mm, 10 mm, 14 mm and 20 mm respectively, and two types of granite, G1 and G2, with size 14 mm and 6 mm, respectively. ...
... 1) The median of the: area (A 50 ), perimeter (P 50 ), minor feret (MinFeret 50 ), major feret (MaxFeret 50 ), aspect ratio (AR 50 ), circularity (C 50 ), roundness (R 50 ). A deeper explanation of these concepts can be found in reference [13]. ...
Article
In this paper, an impulse-based Discrete Element numerical Method (iDEM) included in a physics toolbox, has been used to compact virtual aggregates. Firstly, geometrical properties, such as area, aspect ratio, perimeter, minor and major feret, circularity and roundness, of eleven types of coarse aggregates were measured. Then, a mass of each of these aggregates was compacted under vibration. The aggregate packings’ properties, such as aggregate segregation and orientation, porosity, pore -diameter, -tortuosity, -connectivity, -aspect ratio, -circularity, and -vertical distribution, were measured from Computed Tomography scans. Secondly, the aggregates were simulated using a Perlin noise in spherical primitives, which adjusted their geometry until they achieved realistic morphologies and gradations. iDEM detects contacts between complex shapes, including concavities, and computes the interaction between large amounts of complex objects. Results show that the properties from the packing experiments and simulations are highly comparable. This paper demonstrates the capacity of the physics toolbox to simulate granular materials effectively.
Article
This study proposes a material discovery framework for porous materials to identify design variable recipes and the corresponding material structures that can be utilized to improve the actual manufacturing process. The effectiveness of the proposed framework has been demonstrated via multi-objective genetic algorithm optimization with regard to permeability and filtration efficiency. A simulation model to generate porous material structures with two layers has been developed with design variables, such as grain diameter, grain shape, and ratio of pore former to base grain. The design variables have been optimized to maximize two objective functions, that is, permeability and filtration efficiency, which have been evaluated by machine-learning-based surrogate models with negligible computational cost as compared to the computational fluid dynamics (CFD) simulations. The surrogate models are updated once or regularly using the generated structures to improve the exploration capability according to the necessity of the optimization process. The proposed framework successfully unveiled design variable recipes and guidelines for obtaining preferable structures with high permeability and filtration efficiency in the actual manufacturing process.