Parallel distributed computing using Python

https://readthedocs.org/projects/mpi4py/downloads/pdf/stable/

MPI for Python

Numerical methods for unilateral problems in solid mechanics

Exact vibration analysis of variable thickness thick annular isotropic and FGM plates

https://www.amcaonline.org.ar/ojs/index.php/cmm/article/download/875/829

MPI for Python: Performance improvements and MPI-2 extensions

A parallel finite element program on a Beowulf cluster

Some experiences on writing a parallel finite element code on a Beowulf cluster are shown. This cluster is made up of seven Pentium III processors connected by Fast Ethernet. The code was written in C++ making use of MPI as message passing library and parallel extensible toolkit for scientific computations. The code presented here is a general framework where specific applications may be written. In particular CFD applications regarding Laplace equations, Navier-Stokes and shallow water flows have been implemented. The parallel performance of this application code is assessed and several numerical results are presented.

A cohesive model for simulating dynamic fracture problems is proposed. The use of an
embedded strong discontinuity finite element recently introduced by Sancho et al. [9] in the context of
quasi-static fracture problems is followed.
Two new ingredients of that model are added to extend the applicability of that formulation to
dynamic fracture: a) the integration of the constitutive law by using the “implex” scheme determining
a very robust procedure; b) the addition of a like-distributed damage law in a parallel direction to the
principal crack allowing for the crack branching capture.
The formulation is particularly apt to capture the most important features of the dynamic crack
propagation problem, such as the crack tip velocity and the crack branching phenomena. In the final
sections of the paper, it is shown some numerical applications of this phenomenon.

/pdf/strong-discontinuity-approach-in-dynamic-fracture-50hxfxshft.pdf

Strong Discontinuity Approach In Dynamic Fracture Simulations.

SUMMARY

A new phenomenological macroscopic constitutive model for the numerical simulation of quasi-brittle fracture and ductile concrete behavior, under general triaxial stress conditions, is presented. The model is particularly addressed to simulate a wide range of confinement stress states, as also, to capture the strong influence of the mean stress value in the concrete failure mechanisms.



The model is based on a two-surface damage-plastic formulation. The mechanical behavior in different domains of the stress space is separately described by means of a quasi-brittle or ductile material response: 



(i) For positive values of the mean stress (tensile states), an isotropic continuum damage model with strain softening is considered. In this context, and in order to avoid the Boundary Value Problem ill-posedness induced by the softening law, a regularization technique based on the Continuum Strong Discontinuity Approach (CSDA) is adopted, which results equivalent to a damage model with embedded cohesive cracks providing anisotropic responses.




(ii) A plastic model governs the material behavior when the mean stress is negative (confinement states). It is based on the classical plastic flow theory. In particular, a yield criterion similar to that of Willam and coauthors, which depends on the three stress invariants, is used. Additional features defining the plastic response are: an isotropic strain hardening law and a non-associative flow rule.






The paper presents the numerical implementation of the model using an efficient integration algorithm, namely, the Impl-Ex scheme. Several widely known experimental tests (such as uniaxial, biaxial and triaxial tests) carried out on concrete specimens are used to calibrate and validate the performance of the proposed formulation. Finally, a classical 2D reinforced concrete beam example is analyzed in order to show the predictive capability of the model in structural analysis applications. Copyright © 2011 John Wiley & Sons, Ltd.

/pdf/a-macroscopic-damage-plastic-constitutive-law-for-modeling-32gv1kyk2f.pdf

Victorio E. Sonzogni

Papers

A parallel finite element program on a Beowulf cluster

A parallel finite element program on a Beowulf cluster

Strong Discontinuity Approach In Dynamic Fracture Simulations.

A macroscopic damage‐plastic constitutive law for modeling quasi‐brittle fracture and ductile behavior of concrete

Composite mesh concept based FEM error estimation and solution improvement