Multiscale modeling of polycrystalline materials: A boundary element approach to material degradation and fracture

2015 ◽  
Vol 289 ◽  
pp. 429-453 ◽  
Author(s):  
I. Benedetti ◽  
M.H. Aliabadi
Keyword(s):  
Boundary Element ◽  
Multiscale Modeling ◽  
Polycrystalline Materials ◽  
Material Degradation ◽  
Element Approach

Micromechanical Boundary Element Modelling of Transgranular and Intergranular Cohesive Cracking in Polycrystalline Materials

2016 ◽  
Vol 713 ◽  
pp. 54-57
Author(s):  
G. Geraci ◽  
M.H. Ferri Aliabadi
Keyword(s):  
Boundary Element ◽  
Voronoi Tessellation ◽  
Polycrystalline Materials ◽  
Element Formulation ◽  
Physical Consideration ◽  
Cohesive Model ◽  
Material Orientation ◽  
Element Approach ◽  
Specific Material ◽  
Cohesive Energies

In this paper a cohesive formulation is proposed for modelling intergranular and transgranular damage and microcracking evolution in brittle polycrystalline materials. The model uses a multi region boundary element approach combined with a dual boundary element formulation. Polycrystalline microstructures are created through a Voronoi tessellation algorithm. Each crystal has an elastic orthotropic behaviour and specific material orientation. Transgranular surfaces are inserted as the simulation evolves and only in those grains that experience stress levels high enough for the nucleation of a new potential crack. Damage evolution along (inter-or trans-granular) interfaces is then modelled using cohesive traction separation laws and, upon failure, frictional contact analysis is introduced to model separation, stick or slip. Moreover some physical consideration based on cohesive energies were made, in order to guarantee the cohesive model in consideration was appropriate for the purpose of this work. Finally numerical simulations have been performed to demonstrate the validity of the proposed formulation in comparison with experimental observations and literature results.

scholarly journals Multiscale Modeling of EEG/MEG Response of a Compact Cluster of Tightly Spaced Pyramidal Neocortical Neurons

2020 ◽  
pp. 195-211
Author(s):  
Sergey N. Makarov ◽  
Jyrki Ahveninen ◽  
Matti Hämäläinen ◽  
Yoshio Okada ◽  
Gregory M. Noetscher ◽  
...  
Keyword(s):  
High Resolution ◽  
Boundary Element ◽  
Multiscale Modeling ◽  
Cluster Size ◽  
Fast Multipole Method ◽  
Head Model ◽  
Current Dipole ◽  
Neocortical Neurons ◽  
Dipole Sources ◽  
Compact Cluster

AbstractIn this study, the boundary element fast multipole method or BEM-FMM is applied to model compact clusters of tightly spaced pyramidal neocortical neurons firing simultaneously and coupled with a high-resolution macroscopic head model. The algorithm is capable of processing a very large number of surface-based unknowns along with a virtually unlimited number of elementary microscopic current dipole sources distributed within the neuronal arbor.The realistic cluster size may be as large as 10,000 individual neurons, while the overall computation times do not exceed several minutes on a standard server. Using this approach, we attempt to establish how well the conventional lumped-dipole model used in electroencephalography/magnetoencephalography (EEG/MEG) analysis approximates a compact cluster of realistic neurons situated either in a gyrus (EEG response dominance) or in a sulcus (MEG response dominance).

Microstructure and Fracture in Asphalt Mixtures Using a Boundary Element Approach

2004 ◽  
Vol 16 (2) ◽  
pp. 116-121 ◽  
Author(s):  
B. Birgisson ◽  
C. Soranakom ◽  
J. A. L. Napier ◽  
R. Roque
Keyword(s):  
Boundary Element ◽  
Asphalt Mixtures ◽  
Element Approach
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