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Anisotropic finite element modelling of traumatic brain injury: A voxel-based approach
, Article Scientia Iranica ; Volume 28, Issue 3 B , 2021 , Pages 1271-1283 ; 10263098 (ISSN) ; Farahmand, F ; Ahmadian, M. T ; Masjoodi, S ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
A computationally efficient 3D human head finite element model was constructed. The model includes the mesoscale geometrical details of the brain including the distinction between white and grey matter, sulci and gyri, the ventricular system, foramen magnum, and cerebrospinal fluid. The heterogeneity and anisotropy from diffusion tensor imaging data were incorporated by applying a one-to-one voxel-based correspondence between diffusion voxels and finite elements. The voxel resolution of the model was optimized to obtain a trade-off between reduced computational cost and higher geometrical details. Three sets of constitutive material properties were extracted from the literature to validate...
On Quantification of Seismic Performance Factors for Integral Abutment Bridges
, M.Sc. Thesis Sharif University of Technology ; Maleki, Shervin (Supervisor)
Abstract
Integral abutment bridges (IABs) are bridges in which the deck is cast monolithically with abutment backwalls. These bridges are also jointless through deck length, due to which they act as a frame in their longitudinal direction. These differences with common seat-type bridge construction, have made IABs more economical to build and maintain and superior in seismic performance. As such, in various countries, this method of construction have been prescribed whenever possible. As an instance, integral construction is mandatory for bridges up to 60 meters in total length in England. IABs have become more of a geotechnical problem rather than simple structural problem of conventional bridges in...
Effect of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete gravity dams
, Article Frontiers of Structural and Civil Engineering ; Volume 15, Issue 2 , 2021 , Pages 346-363 ; 20952430 (ISSN) ; Mohammadnezhad, H ; Ghaemian, M ; Sharif University of Technology
Higher Education Press Limited Company
2021
Abstract
Seismic modeling of massive structures requires special caution, as wave propagation effects significantly affect the responses. This becomes more crucial when the path-dependent behavior of the material is considered. The coexistence of these conditions renders numerical earthquake analysis of concrete dams challenging. Herein, a finite element model for a comprehensive nonlinear seismic simulation of concrete gravity dams, including realistic soil-structure interactions, is introduced. A semi-infinite medium is formulated based on the domain reduction method in conjunction with standard viscous boundaries. Accurate representation of radiation damping in a half-space medium and wave...