Alejandro Mota
California Institute of Technology
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Publication
Featured researches published by Alejandro Mota.
Journal of Biomechanics | 2008
Tamer El Sayed; Alejandro Mota; Fernando Fraternali; M. Ortiz
In this paper, a fully variational constitutive model of soft biological tissues is formulated in the finite strain regime. The model includes Ogden-type hyperelasticity, finite viscosity, deviatoric and volumetric plasticity, rate and microinertia effects. Variational updates are obtained via time discretization and pre-minimization of a suitable objective function with respect to internal variables. Genetic algorithms are used for model parameter identification due to their suitability for non-convex, high dimensional optimization problems. The material behavior predicted by the model is compared to available tests on swine and human brain tissue. The ability of the model to predict a wide range of experimentally observed behavior, including hysteresis, cyclic softening, rate effects, and plastic deformation is demonstrated.
International Journal for Numerical Methods in Engineering | 2008
Alejandro Mota; Jaroslaw Knap; M. Ortiz
An approach for the topological representation of simplicial finite element meshes as graphs is presented. It is shown that by using a graph, the topological changes induced by fracture reduce to a few, local kernel operations. The performance of the graph representation is demonstrated and analyzed, using as reference the 3D fracture algorithm by Pandolfi and Ortiz [22]. It is shown that the graph representation initializes in O(N{sub E}{sup 1.1}) time and fractures in O(N{sub I}{sup 1.0}) time, while the reference implementation requires O(N{sub E}{sup 2.1}) time to initialize and O(N{sub I}{sup 1.9}) time to fracture, where NE is the number of elements in the mesh and N{sub I} is the number of interfaces to fracture.
Journal of Physics: Conference Series | 2006
Alejandro Mota; Jaroslaw Knap; M. Ortiz
The brittle fracture of a gypsum cylinder, which is used as an artificial kidney stone in lithotripsy research, is simulated by the use of the finite element method. The cylinder is submerged in water and is subjected to a pressure front parallel to one of its planar faces. The stresses induced by the pressure wave lead to fracture in the interior of the cylinder, with the formation of a spall plane located about 2/3 of the length from the face on which the pressure is applied. We show that the simulation reproduces the salient features of experimental observations.
Computer Methods in Applied Mechanics and Engineering | 2008
Tamer El Sayed; Alejandro Mota; Fernando Fraternali; M. Ortiz
Computational Mechanics | 2006
Q. Yang; Alejandro Mota; M. Ortiz
Computational Mechanics | 2006
Kerstin Weinberg; Alejandro Mota; M. Ortiz
Computational Mechanics | 2009
Tamer El Sayed; Willis Mock; Alejandro Mota; Fernando Fraternali; M. Ortiz
International Journal for Numerical Methods in Engineering | 2005
Q. Yang; Alejandro Mota; M. Ortiz
Computational Mechanics | 2003
Alejandro Mota; William S. Klug; M. Ortiz; Anna Pandolfi
Archive | 2002
M. Ortiz; Alejandro Mota