Papers by Eduardo Campello
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2020
This work presents a computational model for the simulation of problems involving thermo-mechanic... more This work presents a computational model for the simulation of problems involving thermo-mechanically active particles forming discrete particle systems. Our approach is based on the discrete element method for description of the particles' dynamics, combined with simple heat transfer equations to describe the various thermal effects that may take place when the system is excited by temperature gradients and external heat sources. We are able to track the motion of the particles and their thermal states over time under the influence of body (e.g., gravitational) forces, contact and friction forces (and the related moments w.r.t. the particles' centers), as well as applied heat from external devices, heat transfer through conduction (at the particles' interfaces upon contact with other particles and objects), convective cooling and radiative effects. Numerical examples are provided to validate our scheme and illustrate its applicability to the simulation of a wide range of engineering applications. We believe that simple, consistent particle models of the type as shown here may be a useful tool to the modeling of discrete particle systems that are consisted of thermo-mechanically active particles and, in a broader sense, many other multiphysical discrete systems. Particles • Thermal effects • Coupled thermo-mechanics • Multiphysical particle systems • Discrete element method (DEM)
International Journal for Multiscale Computational Engineering, 2019
In many emerging applications, the controlled infiltration of specially designed particle-laden f... more In many emerging applications, the controlled infiltration of specially designed particle-laden fluids into porous media is critical. The added materials are often chosen with the objective to mechanically, electrically, or magnetically functionalize the overall material. Because of the increased viscosity of particle-laden fluids and the pore-dependent permeability of the medium to be infiltrated, there is a rich choice of parameters that govern the overall process: (i) the base viscosity of the solvent, (ii) the volume fraction of particles in the fluid, (iii) the pore volume fraction of the porous medium, and (iv) the absolute permeability of the medium. This paper develops Darcy-law-like expressions relating the infiltration flow rate of particle-laden fluids to the pressure gradient on porous solids, as a function of the four above parameters. General trends of the process may be satisfactorily described with the derived analytical expressions, yet at an affordable cost on accuracy for rapid daily design analysis. The paper then develops direct, large-scale numerical simulations based on the discrete element method to illustrate the practical use of the proposed relations.
Computer Modeling in Engineering and Sciences
This work deals with the bombardment of a stream of particles possessing varying mean particle si... more This work deals with the bombardment of a stream of particles possessing varying mean particle size, velocity and aspect ratio into a cell that has fixed (known) compliance characteristics. The particles are intended to penetrate the cell membrane causing zero or minimum damage and deliver foreign substances (which are attached to their surfaces) to the interior of the cell. We adopt a particle-based (discrete element method) computational model that has been recently developed by the authors to describe both the incoming stream of particles and the cell membrane. By means of parametric numerical simulations, treating the stream’s mean particle size, velocity and aspect ratio as random variables, we explore the synergy between these parameters and identify basic trends as to how changes in the input parameters affect the output results, and as to what are the best combinations of parameter values that lead to (i) the highest amount of particle delivery and (ii) the lowest level of m...
Computational Particle Mechanics, 2015
In this work, we show how a vector parameterization of rotations can be adopted to describe the r... more In this work, we show how a vector parameterization of rotations can be adopted to describe the rotational motion of particles within the framework of the discrete element method (DEM). It is based on the use of a special rotation vector, called Rodrigues rotation vector, and accounts for finite rotations in a fully exact manner. The use of fictitious entities such as quaternions or complicated structures such as Euler angles is thereby circumvented. As an additional advantage, stick-slip friction models with interparticle rolling motion are made possible in a consistent and elegant way. A few examples are provided to illustrate the applicability of the scheme. We believe that simple vector descriptions of rotations are very useful for DEM models of particle systems.
International journal for numerical methods in biomedical engineering, 2014
In this paper, we propose a simple computational framework for the rapid simulation of the delive... more In this paper, we propose a simple computational framework for the rapid simulation of the delivery of substances into cells. Our approach treats the substances and the cell membrane as a collection of particles forming a discrete dynamical system, which is described by Newtonian equations in a purely mechanistic way. Detailed aspects about the modeling of particle interactions are discussed and resolved. The main advantage of such an approach is that it can offer a good qualitative picture of the delivery mechanism without the need to resort to detailed descriptions of the complex intermolecular interactions that are observed at small scales of the cell membrane. A numerical time integration scheme is formulated for solution of the system dynamics, and examples of simulations are provided. Computational particle-based models render reliable and fast simulation tools. We believe they can be very useful to help advance the design of delivery systems.
Rem: Revista Escola de Minas, 2007
The geometrically-exact finite-strain variable-thickness shell model of [1] is reviewed in this p... more The geometrically-exact finite-strain variable-thickness shell model of [1] is reviewed in this paper and extended to the case of metallic elastoplastic shells. Isotropic elasticity and von Mises yield criterion with isotropic hardening are considered. The model is implemented within a triangular finite element and is briefly assessed by means of two numerical examples.
Computational Mechanics, 2011
A fully conserving algorithm is developed in this paper for the integration of the equations of m... more A fully conserving algorithm is developed in this paper for the integration of the equations of motion in nonlinear rod dynamics. The starting point is a re-parameterization of the rotation field in terms of the so-called Rodrigues rotation vector, which results in an extremely simple update of the rotational variables. The weak form is constructed with a non-orthogonal projection corresponding to the application of the virtual power theorem. Together with an appropriate time-collocation, it ensures exact conservation of momentum and total energy in the absence of external forces. Appealing is the fact that nonlinear hyperelastic materials (and not only materials with quadratic potentials) are permitted without any prejudice on the conservation properties. Spatial discretization is performed via the finite element method and the performance of the scheme is assessed by means of several numerical simulations.
CISM International Centre for Mechanical Sciences, 2010
This work presents a fully nonlinear Kirchhoff-Love shell model. In contrast with shear flexible ... more This work presents a fully nonlinear Kirchhoff-Love shell model. In contrast with shear flexible models, our approach is based on the Kirchhoff-Love theory for thin shells, so that transversal shear deformation is not accounted for. We define energetically conjugated cross-sectional generalized stresses and strains. The fact that both the first Piola-Kirchhoff stress tensor and the deformation gradient appear as primary
CISM International Centre for Mechanical Sciences, 2010
This work presents a fully nonlinear Kirchhoff-Love shell model. In contrast with shear flexible ... more This work presents a fully nonlinear Kirchhoff-Love shell model. In contrast with shear flexible models, our approach is based on the Kirchhoff-Love theory for thin shells, so that transversal shear deformation is not accounted for.
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Papers by Eduardo Campello