Journal articles on the topic 'Hybrid Particle-Element Approach'
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Fahrenthold, E. P., and J. C. Koo. "Hybrid Particle-Element Bond Graphs for Impact Dynamics Simulation." Journal of Dynamic Systems, Measurement, and Control 122, no. 2 (August 10, 1995): 306–13. http://dx.doi.org/10.1115/1.482456.
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Particle methods offer an efficient modeling approach to number of impact dynamics problems not well suited to conventional Eulerian finite difference or Lagrangian finite element methods. Unfortunately, the most popular of these particle methods (smooth particle hydrodynamics) exhibits important deficiencies, in part related to its treatment of boundaries and interparticle tension, and suffers from a rather ad hoc model formulation approach. A hybrid particle-element kinematic scheme and an energy-based, bond graph modeling approach have been combined to produce a new impact dynamics simulation method, free of many problems which have hindered the effective application of various particle and continuum methods. [S0022-0434(00)00602-X]
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Johnson, G. R., S. R. Beissel, and C. A. Gerlach. "Another approach to a hybrid particle-finite element algorithm for high-velocity impact." International Journal of Impact Engineering 38, no. 5 (May 2011): 397–405. http://dx.doi.org/10.1016/j.ijimpeng.2011.01.002.
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Zhang, Ri, Hyeong-Joo Kim, and Peter Rey Dinoy. "Particle Flow Simulation Based on Hybrid IMB-DEM-LBM Approach with New Solid Fraction Calculation Scheme." Applied Sciences 11, no. 8 (April 12, 2021): 3436. http://dx.doi.org/10.3390/app11083436.
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A new coupling method, immersed moving boundary–discrete element method–lattice Boltzmann method (IMB-DEM-LBM), is proposed to simulate particle flow for application in soil mechanics or coastal engineering. In this study, LBM fluid is simulated on the regular Eulerian grid and Lagrangian particle motion is governed by DEM while IMB couples the two algorithms. The new method is promising and robust as it resolves numerical instability near the particle boundary caused by mesh distortion in the conventional grid method. In IMB, the interface lattice solid fraction determines the distribution function ratio of non-equilibrium bounce back and Bhatnagar-Gross-Krook (BGK) collision. The non-equilibrium bounce back at moving boundary results in the fluid momentum change and contributes to the hydrodynamic force on particle. For numerical stability, this paper introduces the hydrodynamic force calculation concept from IB (immersed boundary method) to IMB, and at the same time, proposes a new solid fraction calculation method for sphere that divides the intersection into simple sector and triangle, as well as calculates the intersection area by vector. With this method, approximate inaccuracy is overcome while complicated integration is avoided.
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Hebal, Sara, Djamila Mechta, Saad Harous, and Mohammed Dhriyyef. "Hybrid Energy Routing Approach for Energy Internet." Energies 14, no. 9 (April 30, 2021): 2579. http://dx.doi.org/10.3390/en14092579.
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The Energy Internet (EI) has been proposed as an evolution of the power system in order to improve its efficiency in terms of energy generation, transmission and consumption. It aims to make the use of renewable energy effective. Herein, the energy router has been considered the crucial element that builds the net structure between the different EI components by connecting and controlling the bidirectional power and data flow. The increased use of renewable energy sources in EI has contributed to the creation of a new competitive energy trading market known as peer-to-peer energy trading, which enables each component to be part of the trading process. As a consequence, the concept of energy routing is increasingly relevant. In fact, there are three issues that need to be taken into account during the energy routing process: the subscriber matching, the energy-efficient path and the transmission scheduling. In this work, we first proposed a peer-to-peer energy trading scheme to ensure a controllable and reliable EI. Then, we introduced a new energy routing approach to address the three routing issues. A subscriber matching mechanism is designed to determine which producer/producers should be assigned for each consumer by optimizing the energy cost and transmission losses. This mechanism provides a solution for both mono and multi-source consumers. An improved ant colony optimization-based energy routing protocol was developed to determine a non-congestion minimum loss path. For the multi-source consumer case, an energy particle swarm optimization algorithm was proposed to choose a set of producers and to decide the amount of energy that should be collected from each producer to satisfy the consumer request. Finally, the performance of the proposed protocol, in terms of power losses, cost and computation time was compared to the best existing algorithms in the literature. Simulation results show the effectiveness of the proposed approach.
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Radvilaitė, Urtė. "THE APPLICATION OF SPHERICAL HARMONICS FOR DESCRIBING A CUBE-SHAPE PARTICLE / SFERINIŲ HARMONINIŲ FUNKCIJŲ TAIKYMAS KUBO FORMOS DALELEI APRAŠYTI." Mokslas – Lietuvos ateitis 6, no. 6 (March 5, 2015): 682–85. http://dx.doi.org/10.3846/mla.2014.776.
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The paper disccusses various models for discrete element methods of modelling particle shapes. The multi-sphere method is most frequently used, though a polyhedral approach and a hybrid sphero-polyhedral model can also be introduced. All above mentioned methods precisely approximate particle shapes, and difficulties in modelling contact between particles arise. Thus, there is a need to have an universal method that gives the analytical expression of the shape. For this purpose, spherical harmonics have been introduced. The article presents the concept of the spherical harmonics model and experimental results describing the cube-shape particle. Šiame straipsnyje aptariami įvairūs diskrečiųjų elementų metodo modeliai, taikomi dalelių formoms modeliuoti. Dažniausiai taikomas kelių sferų modelis, bet yra pristatyti ir daugiasienis modelis bei mišrus sferos daugiasienis modelis. Nors aptariami metodai neblogai apkroksimuoja dalelių formą, atsiranda sunkumų skaičiuojant dalelių kontaktą. Todėl reikalingas universalus metodas, leidžiantis gauti analitinę dalelės formos išraišką. Būtent tokiam tikslui naudojamos sferinės harmoninės funkcijos. Straipsnyje pristatomas sferinių funkcijų modelis bei pateikiami eksperimento rezultatai kubo formos dalelei aprašyti.
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Bohdal, Łukasz, Agnieszka Kułakowska, Radoslaw Patyk, and Marcin Kulakowski. "Numerical Investigations of the Effect of Process Parameters on Residual Stresses, Strains and Quality of Final Product in Blanking Using SPH Method." Materials Science Forum 862 (August 2016): 238–45. http://dx.doi.org/10.4028/www.scientific.net/msf.862.238.
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The shearing process such as the blanking of sheet metals has been used often to prepare workpieces for subsequent forming operations. This process consists in separating a blank from a sheet by means of a high-localized shear deformation due to the action of a punch. Blanking modelling is becoming an increasingly important tool in gaining understanding and improving this process. At the moment a fundamental problem in numerical modelling of blanking processes is an excessive element distortion in a finite-element simulation. In this study, we present a hybrid modelling approach, SPH (smoothed particle hydrodynamics) coupled FEM method to simulate the blanking process. This new approach involves several advantages compared to the traditional finite element method for example: neglect mesh tangling and distortion problems, does not need to use material separation criterion. The physical, mathematical and computer model of the process is elaborated. The application in ANSYS/LS-DYNA program is developed. The examination and analysis of influence of process technological parameters for example: the clearance, tool geometry, blanking velocity on residual stresses, strains and quality of final product using the SPH method is analyzed. The results of computer simulations can be used to forecasting quality of the parts optimization.
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Patnaik, Amar, Ritesh Kaundal, Alok Satapathy, Sandhyarani Biswas, and Pradeep Kumar. "Solid Particle Erosion of Particulate Filled Short Glass Fiber Reinforced Polyester Resin Composites." Advanced Materials Research 123-125 (August 2010): 213–16. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.213.
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Fiber reinforced composite materials have been used in main parts of structures; an accurate evaluation of their erosion behavior becomes very important. In this study, short glass fibre reinforced polyester based isotropic polymer composites are fabricated with five different fibre weight-fractions. The effect of various operational variables, material parameters and their interactive influences on erosive wear behavior of these composites has been studied systematically. After systematic analysis of solid particle erosion for all the five composites, 30wt% short glass fiber reinforced polyester based composite shows better erosion resistance. In order to improve the erosion resistance further ceramic silicon carbide particle is reinforced with the 30wt% glass-polyester based hybrid composites. A finite element (FE) model (LS-DYNA) of erosive wear is established for damage assessment and validated by a well designed set of experiments. For this, the design of experiments approach using Taguchi’s orthogonal arrays design is used. It is recognized that there is a good agreement between the computational and experimental results, and that the proposed simulation method is very useful for the evaluation of damage mechanisms.
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Saha, Abir, Santosh Kumar, Divya Zindani, and Sumit Bhowmik. "Micro-mechanical analysis of the pineapple-reinforced polymeric composite by the inclusion of pineapple leaf particulates." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 235, no. 5 (February 1, 2021): 1112–27. http://dx.doi.org/10.1177/1464420721990851.
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The present study is focused on investigating the effect of the micro-mechanical properties of the natural fiber- (pineapple leaf fiber) reinforced polymeric composites by the addition of pineapple leaf micro-particulates. For the investigation, a two-step approach has been used. In the first step, finite element method-based analysis has been used to characterize the tensile and shear properties of the pineapple leaf fiber-reinforced polymeric composites (FRP) and pineapple paticulate-reinforced polymeric composites (PRC), and the adopted finite element method-based analysis has been validated through the experimental approach. In the second step, the validated finite element method-based analysis has been used to characterize the micro-mechanical properties of the hybrid fiber-reinforced polymeric composites (HFRP) fabricated using the pineapple leaf micro-particle embedded epoxy as a matrix material and the pineapple leaf fiber has been used as reinforcing material. It has been observed through the analysis that the micro-mechanical properties of HFRP were superior to that of FRP. There has been a 10.16% increment in Young’s modulus in the longitudinal direction and a 26.36% increment in Young’s modulus in the transverse direction for HFRP over FRP. Further, a 9.91% increment for in-plane shear modulus and 26.17% increment in outer-plane shear modulus have been observed for HFRP in comparison to FRP. These results suggest that pineapple leaf particulates are good reinforcing materials to enhance the transverse direction and outer plane micro-mechanical properties of the fiber-reinforced composite.
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Kulkarni, S. G., Achchhe Lal, and J. V. Menghani. "Effect of reinforcement type and porosity on strength of metal matrix composite." International Journal of Computational Materials Science and Engineering 05, no. 01 (March 2016): 1650006. http://dx.doi.org/10.1142/s2047684116500068.
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In the present work, experimental investigation and the numerical analysis are carried out for strength analysis of A356 alloy matrix composites reinforced with alumina, fly ash and hybrid particle composites. The combined strengthening effect of load bearing, Hall–Petch, Orowan, coefficient of thermal expansion mismatch and elastic modulus mismatch is studied for predicting accurate uniaxial stress–strain behavior of A356 based alloy matrix composite. The unit cell micromechanical approach and nine noded isoparametric finite element analysis (FEA) is used to investigate the yield failure load by considering material defect of porosity as fabrication errors in particulate composite. The Ramberg–Osgood approach is considered for the linear and nonlinear relationship between stress and strain of A356 based metal matrix composites containing different amounts of fly ash and alumina reinforcing particles. A numerical analysis of material porosity on the stress strain behavior of the composite is performed. The literature and experimental results exhibit the validity of this model and confirm the importance of the fly ash as the cheapest and low density reinforcement obtained as a waste by product in thermal power plants.
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Shankar, K., and N. Jinesh. "Damage identification using combined acceleration and voltage matching with one-dimensional PZT patch model." Multidiscipline Modeling in Materials and Structures 14, no. 1 (March 5, 2018): 40–64. http://dx.doi.org/10.1108/mmms-05-2017-0030.
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Purpose The purpose of this paper is to provide an effective and simple technique for structural parameter identification, particularly to identify multiple cracks in a structure using simultaneous measurement of acceleration responses and voltage signals from PZT patches which is a multidisciplinary approach. A hybrid element constituted of one-dimensional beam element and a PZT sensor is used with reduced material properties which is very convenient for beams and is a novel application for inverse problems. Design/methodology/approach Multi-objective formulation is used whereby structural parameters are identified by minimizing the deviation between the predicted and measured values from the PZT patch and acceleration responses, when subjected to excitation. In the proposed method, a patch is attached to either end of the fixed beam. Using particle swarm optimization algorithm, normalized fitness functions are defined for both voltage and acceleration components with weighted aggregation multi-objective optimization technique. The signals are polluted with 5 percent Gaussian noise to simulate experimental noise. The effects of various weighting factors for the combined objective function are studied. The scheme is also experimentally validated by identification of cracks in a fixed-fixed beam. Findings The numerical and experimental results shows that significant improvement in accuracy of damage detection is achieved by the combined multidisciplinary method, when compared with only voltage or only acceleration-matching method as well as with other methods. Originality/value The proposed multidisciplinary crack identification approach, which is based on one-dimensional PZT patch model as well as conventional acceleration method, is not reported in the literature.
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Fan, Ming, James McClure, Yanhui Han, Nino Ripepi, Erik Westman, Ming Gu, and Cheng Chen. "Using an Experiment/Simulation-Integrated Approach To Investigate Fracture-Conductivity Evolution and Non-Darcy Flow in a Proppant-Supported Hydraulic Fracture." SPE Journal 24, no. 04 (May 14, 2019): 1912–28. http://dx.doi.org/10.2118/195588-pa.
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Summary Optimizing proppant-pack conductivity in a hydraulic fracture is of critical importance to sustaining effective and economical production of petroleum hydrocarbons. In this study, a hybrid, experiment/simulation-integrated workflow, which combines the discrete element method (DEM) and the lattice Boltzmann (LB) method with laboratory-measured load-embedment correlations, was developed to advance the understanding of fracture-conductivity evolution from partial-monolayer to multilayer concentrations. The influence of compressive stress and proppant-diameter heterogeneity on non-Darcy flow behaviors was also investigated. The DEM method was used to simulate effective-stress increase and the resultant proppant-particle compaction and rearrangement. Proppant-embedment distance was then determined using an empirical correlation obtained by fitting experimental data. The final pore structure of the proppant pack was imported into the LB simulator as interior boundary conditions of fluid-flow modeling in the calculation of time-dependent permeability of the proppant pack. To validate the integrated workflow, proppant-pack conductivity as a function of increasing proppant concentration was simulated and then compared with laboratory data. Good agreement was observed between the workflow-derived and laboratory-measured fracture-conductivity vs. proppant-concentration curves. Furthermore, the role of proppant size, size heterogeneity, and closure pressure on the optimal partial-monolayer proppant concentration was investigated. The optimal partial-monolayer proppant concentration has important engineering implications, because one can achieve a considerable fracture conductivity using a partial-monolayer proppant structure, which has much lower material costs compared with the conventional multilayer proppant structures. To investigate the effect of non-Darcy flow on fracture conductivity, three proppant packs with the same average diameter but different diameter distributions were generated. Specifically, the coefficient of variation (COV) of diameter, defined as the ratio of standard deviation of diameter to mean diameter, was used to characterize the heterogeneity of particle size. The results of this research provide fundamental insights into the multiphysics processes regulating the conductivity evolution of a proppant-supported hydraulic fracture, as well as the role of compressive stress and proppant-size heterogeneity in non-Darcy flows.
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Wang, Jinge, Shun Wang, Aijun Su, Wei Xiang, Chengren Xiong, and Philipp Blum. "Simulating landslide-induced tsunamis in the Yangtze River at the Three Gorges in China." Acta Geotechnica 16, no. 8 (January 23, 2021): 2487–503. http://dx.doi.org/10.1007/s11440-020-01131-3.
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AbstractLandslide-induced tsunamis may cause fatalities, damages and financial losses. In the Three Gorges Reservoir Area of China, several large landslides are still unstable and persistently creeping toward the Yangtze River. In this paper, we investigate the impacts of landslide-induced tsunamis in the Three Gorges Reservoir by using a hybrid numerical approach. One of the largest unstable mass in this area, the Huangtupo landslide, is chosen as the study object. First, the landslide deformation and initiating velocities are obtained by using the finite-discrete element method. The landslide-induced tsunamis and their impacts on shipping on the Yangtze River are then investigated through smooth particle hydrodynamics modelling. Our results reveal that an approximately 80% reduction in shear strength of the tip in the landslide will lead to catastrophic failure of the landslide, with sliding velocities of up to 8 m/s. Subsequently, such a collapse may initiate a river tsunami, propagating up to 9 m on the nearby reservoir banks within 3 km. The impacts on surrounding floating objects, such as surges and sways, heaves and rolls, are up to 110 m, 8 m and 6°, respectively. The simulations indicate that although the likelihood of a catastrophic failure of the whole landslide is low, the partial sliding still poses severe threat to the nearby reservoir banks and shipping on the Yangtze River. Thus, we recommend continuous monitoring as well as landslide early warning systems at this and also other hazardous sites in this area.
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Moayedi, Hossein, Dieu Tien Bui, Mesut Gör, Biswajeet Pradhan, and Abolfazl Jaafari. "The Feasibility of Three Prediction Techniques of the Artificial Neural Network, Adaptive Neuro-Fuzzy Inference System, and Hybrid Particle Swarm Optimization for Assessing the Safety Factor of Cohesive Slopes." ISPRS International Journal of Geo-Information 8, no. 9 (September 4, 2019): 391. http://dx.doi.org/10.3390/ijgi8090391.
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In this paper, a neuro particle-based optimization of the artificial neural network (ANN) is investigated for slope stability calculation. The results are also compared to another artificial intelligence technique of a conventional ANN and adaptive neuro-fuzzy inference system (ANFIS) training solutions. The database used with 504 training datasets (e.g., a range of 80%) and testing dataset consists of 126 items (e.g., 20% of the whole dataset). Moreover, variables of the ANN method (for example, nodes number for each hidden layer) and the algorithm of PSO-like swarm size and inertia weight are improved by utilizing a total of 28 (i.e., for the PSO-ANN) trial and error approaches. The key properties were fed as input, which were utilized via the analysis of OptumG2 finite element modelling (FEM), containing undrained cohesion stability of the baseline soil (Cu), angle of the original slope (β), and setback distance ratio (b/B) where the target is selected factor of safety. The estimated data for datasets of ANN, ANFIS, and PSO-ANN models were examined based on three determined statistical indexes. Namely, root mean square error (RMSE) and the coefficient of determination (R2). After accomplishing the analysis of sensitivity, considering 72 trials and errors of the neurons number, the optimized architecture of 4 × 6 × 1 was determined to the structure of the ANN model. As an outcome, the employed methods presented excellent efficiency, but based on the ranking method, the PSO-ANN approach might have slightly better efficiency in comparison to the algorithms of ANN and ANFIS. According to statistics, for the proper structure of PSO-ANN, the indexes of R2 and RMSE values of 0.9996, and 0.0123, as well as 0.9994 and 0.0157, were calculated for the training and testing networks. Nevertheless, having the ANN model with six neurons for each hidden layer was formulized for further practical use. This study demonstrates the efficiency of the proposed neuro model of PSO-ANN in estimating the factor of safety compared to other conventional techniques.
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Agaguseynova, Minirа M., and Mehriban R. Mikailova. "FORMATION OF Ru NANO-COMPOSITES." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 3 (February 27, 2018): 45. http://dx.doi.org/10.6060/tcct.20186103.5639.
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Researches of polymer immobilized nanoparticles of ruthenium have been carried out by frontal polymerization (FP) of ruthenium acrylonitrile (AN) complex in the presence of inorganic carrier. Assessment of their catalytic properties in the hydrogenation reaction of unsaturated compounds has been done. Effective and selective organo-inorganic catalyst has been synthesized on the basis of akrylonitril complex and its reactivity in the hydrogenation reaction of cyclohexen has been investigated. Synthesis of akrylonitril complex of ruthenium on the surface of mineral carrier SiO2 silica, its further polymerization and reduction leads to the formation of polymer-inorganic composite including nano-size particle of Ru stabilized by polymer matrix and inorganic carrier. The offered method is a new approach in the catalyst preparing. Synthesized samples of Ru- nano composetes have been studied by methods of element analysis, IR-spectroscopy and X-ray analysis. There are wide diffraction peaks at 300-800 °C range in the X-rays patterns of the obtained samples wich correspond to crystallic ruthenium. Broadening diffraction maximums testifies ultradisperse state of particles. Microporous structure with pore sizes to 20 nm and their uniform size distribution are typical for obtained nano composites. It has been determined that specific surface of carriers decreases after polymerization of RuAN on the surface, though it is bigger than S spec. of the polymerization product in SiO2 absence. Obtained hybride nano composites have developed surface and porous structure which provide accessibility of active centers of catalyst for reagents and their high activity in the researched catalytic reaction. Formation conditions of Ru nanoparticles influence on catalytic properties of the studied composites, for example, the use of various regimes of frontal polymerization in inert medium. With the increase of the reduction treatment temperature of nano-composites the hydrogenation rate of cyclohexene reduces, the reason of which is the integration of Ru particles in the obtaining of nano composites at high temperatures. It should be mentioned that after hydrogenation the main ruthenium mass in poly-RuAN (90%) will have zero valency. The polymer matrix reduces. It is also subjected to changes and it confirms by spectrum broadening. Thus, the synthesized hybridization of polymer-immobilized Ru-nanoparticles display high activity in the reaction of cyclohexene hydrogenation and keep their activity during repeated cycles of reactions. Catalytic properties of nano-composites depend on the conditions of their obtaining which influence apparently on the size of forming Ruthenium nanoparticles.Forcitation:Agaguseynova M.M., Mikailova M.R. Formation of Ru nano-composites. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 45-50
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Uma, B., R. Radhakrishnan, D. M. Eckmann, and P. S. Ayyaswamy. "A Hybrid Approach for the Simulation of the Thermal Motion of a Nearly Neutrally Buoyant Nanoparticle in an Incompressible Newtonian Fluid Medium." Journal of Heat Transfer 135, no. 1 (December 6, 2012). http://dx.doi.org/10.1115/1.4007668.
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A hybrid approach consisting of a Markovian fluctuating hydrodynamics of the fluid and a non-Markovian Langevin dynamics with the Ornstein–Uhlenbeck noise perturbing the translational and rotational equations of motion of a nanoparticle is employed to study the thermal motion of a nearly neutrally buoyant nanoparticle in an incompressible Newtonian fluid medium. A direct numerical simulation adopting an arbitrary Lagrangian–Eulerian based finite element method is employed for the simulation of the hybrid approach. The instantaneous flow around the particle and the particle motion are fully resolved. The numerical results show that (a) the calculated temperature of the nearly neutrally buoyant Brownian particle in a quiescent fluid satisfies the equipartition theorem; (b) the translational and rotational decay of the velocity autocorrelation functions result in algebraic tails, over long time; (c) the translational and rotational mean square displacements of the particle obey Stokes–Einstein and Stokes–Einstein–Debye relations, respectively; and (d) the parallel and perpendicular diffusivities of the particle closer to the wall are consistent with the analytical results, where available. The study has important implications for designing nanocarriers for targeted drug delivery. A major advantage of our novel hybrid approach employed in this paper as compared to either the fluctuating hydrodynamics approach or the generalized Langevin approach by itself is that only the hybrid method has been shown to simultaneously preserve both hydrodynamic correlations and equilibrium statistics in the incompressible limit.
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Semmler, Johannes, and Michael Stingl. "On the efficient optimization of optical properties of particulate monolayers by a hybrid finite element approach." Structural and Multidisciplinary Optimization, November 1, 2020. http://dx.doi.org/10.1007/s00158-020-02754-6.
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Abstract This article addresses the numerical simulation and optimization of the optical properties of mono-layered nano-particulate films. The particular optical property of interest is the so-called haze factor, for which a model close to an experimental setup is derived. The numerical solution becomes very involved due to the resulting size of computational domain in comparison to the wave length, rendering the direct simulation method infeasible. As a remedy, a hybrid method is suggested, which in essence consistently combines analytical solutions for the far field with finite element-based solutions for the near field. Using a series of algebraic reformulations, a model with an off- and online component is developed, which results in the computational complexity being reduced by several orders of magnitude. Based on the suggested hybrid numerical scheme, which is not limited to the haze factor as objective function, structural optimization problems covering geometrical and topological parametrizations are formulated. These allow the influence of different particle arrangements to be studied. The article is complemented by several numerical experiments underlining the strength of the method.
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Uma, B., R. Radhakrishnan, D. M. Eckmann, and P. S. Ayyaswamy. "Nanocarrier–Cell Surface Adhesive and Hydrodynamic Interactions: Ligand–Receptor Bond Sensitivity Study." Journal of Nanotechnology in Engineering and Medicine 3, no. 3 (August 1, 2012). http://dx.doi.org/10.1115/1.4007522.
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A hybrid approach combining fluctuating hydrodynamics with generalized Langevin dynamics is employed to study the motion of a neutrally buoyant nanocarrier in an incompressible Newtonian stationary fluid medium. Both hydrodynamic interactions and adhesive interactions are included, as are different receptor–ligand bond constants relevant to medical applications. A direct numerical simulation adopting an arbitrary Lagrangian–Eulerian based finite element method is employed for the simulation. The flow around the particle and its motion are fully resolved. The temperatures of the particle associated with the various degrees of freedom satisfy the equipartition theorem. The potential of mean force (or free energy density) along a specified reaction coordinate for the harmonic (spring) interactions between the antibody and antigen is evaluated for two different bond constants. The numerical evaluations show excellent comparison with analytical results. This temporal multiscale modeling of hydrodynamic and microscopic interactions mediating nanocarrier motion and adhesion has important implications for designing nanocarriers for vascular targeted drug delivery.
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"A Class of Evolutionary Algorithms for Determining Shortest Path Routing in 5G Ultra Dense Heterogeneous Networks." International Journal of Computers and Communications 14 (December 17, 2020). http://dx.doi.org/10.46300/91013.2020.14.11.
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Ultra Dense Network (UDN), an important element of the upcoming 5G networks are characterised by extremely dynamic operations due to the presence and mobility of large number of users spread over small cells of varying sizes. It makes optimal path between the source/destination pairs for communication and data transmission be highly dynamic in nature and hence a challenging issue to deal with. Under such dynamic backdrops, routing procedures have to exhibit robustness, scalability and time efficiency in order to ensure seamless link reliability and Quality of Service (QOS) of the network. In the proposed work, the shortest optimal route of the source and destination pair is found using a combination of evolutionary optimization algorithms namely Genetic Algorithm (GA), Particle Swarm Optimization (PSO) Algorithm and our novel hybrid PSOGA approach which searches for an optimized solution by determining cost functions of individual fitness state and comparing states generated between individual solutions. Application of all the three above mentioned algorithms to the Shortest Path Routing Problem in UDNs and the results obtained have shown that the hybrid PSO-GA comparatively provided enhanced optimized solution.
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Karimzadeh, A., S. S. R. Koloor, M. R. Ayatollahi, A. R. Bushroa, and M. Y. Yahya. "Assessment of Nano-Indentation Method in Mechanical Characterization of Heterogeneous Nanocomposite Materials Using Experimental and Computational Approaches." Scientific Reports 9, no. 1 (October 31, 2019). http://dx.doi.org/10.1038/s41598-019-51904-4.
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Abstract This study investigates the capacity of the nano-indentation method in the mechanical characterization of a heterogeneous dental restorative nanocomposite using experimental and computational approaches. In this respect, Filtek Z350 XT was selected as a nano-particle reinforced polymer nanocomposite with a specific range of the particle size (50 nm to 4 µm), within the range of indenter contact area of the nano-indentation experiment. A Sufficient number of nano-indentation tests were performed in various locations of the nanocomposite to extract the hardness and elastic modulus properties. A hybrid computational-experimental approach was developed to examine the extracted properties by linking the internal behaviour and the global response of the nanocomposite. In the computational part, several representative models of the nanocomposite were created in a finite element environment to simulate the mechanism of elastic-plastic deformation of the nanocomposite under Berkovich indenter. Dispersed values of hardness and elastic modulus were obtained through the experiment with 26.8 and 48.5 percent average errors, respectively, in comparison to the nanocomposite properties, respectively. A disordered shape was predicted for plastic deformation of the equilateral indentation mark, representing the interaction of the particles and matrix, which caused the experiment results reflect the local behaviour of the nanocomposite instead of the real material properties.
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Ostermeier, Peter, Annelies Vandersickel, Stephan Gleis, and Hartmut Spliethoff. "Numerical Approaches for Modeling Gas–Solid Fluidized Bed Reactors: Comparison of Models and Application to Different Technical Problems." Journal of Energy Resources Technology 141, no. 7 (April 19, 2019). http://dx.doi.org/10.1115/1.4043327.
Full textAbstract:
Gas–solid fluidized bed reactors play an important role in many industrial applications. Nevertheless, there is a lack of knowledge of the processes occurring inside the bed, which impedes proper design and upscaling. In this work, numerical approaches in the Eulerian and the Lagrangian framework are compared and applied in order to investigate internal fluidized bed phenomena. The considered system uses steam/air/nitrogen as fluidization gas, entering the three-dimensional geometry through a Tuyere nozzle distributor, and calcium oxide/corundum/calcium carbonate as solid bed material. In the two-fluid model (TFM) and the multifluid model (MFM), both gas and powder are modeled as Eulerian phases. The size distribution of the particles is approximated by one or more granular phases with corresponding mean diameters and a sphericity factor accounting for their nonspherical shape. The solid–solid and fluid–solid interactions are considered by incorporating the kinetic theory of granular flow (KTGF) and a drag model, which is modified by the aforementioned sphericity factor. The dense discrete phase model (DDPM) can be interpreted as a hybrid model, where the interactions are also modeled using the KTGF; however, the particles are clustered to parcels and tracked in a Lagrangian way, resulting in a more accurate and computational affordable resolution of the size distribution. In the computational fluid dynamics–discrete element method (CFD–DEM) approach, particle collisions are calculated using the DEM. Thereby, more detailed interparticulate phenomena (e.g., cohesion) can be assessed. The three approaches (TFM, DDPM, CFD–DEM) are evaluated in terms of grid- and time-independency as well as computational demand. The TFM and CFD–DEM models show qualitative accordance and are therefore applied for further investigations. The MFM (as a variation of the TFM) is applied in order to simulate hydrodynamics and heat transfer to immersed objects in a small-scale experimental test rig because the MFM can handle the required small computational cells. Corundum is used as a nearly monodisperse powder, being more suitable for Eulerian models, and air is used as fluidization gas. Simulation results are compared to experimental data in order to validate the approach. The CFD–DEM model is applied in order to predict mixing behavior and cohesion effects of a polydisperse calcium carbonate powder in a larger scale energy storage reactor.