Links

Software



GNU is not Unix

Debian GNU/Linux

Get Firefox!
dorival

Dorival M Pedroso

Civil Eng, MSc & PhD in Geomechanics


Brief info

My main interests are on Computational Mechanics in the Civil and Mining engineering.

Currently, I work as a Lecturer of Civil Engineering (Geomechanics) at The University of Queensland, Australia, Golder Geomechanics Centre

I have been developing constitutive equations for a range of soils and other granular materials, mostly based upon the results of conventional and true triaxial and hollow cylinder testing of materials. These models have addressed complicated soil behaviour such as soil-water-air multiphase interaction, over-consolidation, structure dependency, stress-path dependency, and change of stiffness due to cyclic loading. They rely heavily on refined concepts from continuum mechanics, with or without large deformation.

For the governing partial differential equations (Differential Algebraic System - DAS), I have been studying different algorithms for numerical solutions in time (Runge-Kutta implicit/explicit) and space via the finite volume method (FVM), finite element method (FEM), discrete element method (DEM), and the material point method (MPM). These algorithms include 3D geometry and coupling between soil (unsaturated) and water, in addition to thermo-hydro-chemo-mechanical (THCM) coupling.

In addition, I have been developing computer tools for the simulation of 3D problems in mechanics. A complete programming library (MechSys - Open Library for Mechanical Systems) was developed and made available for free with open source on the web (http://mechsys.nongnu.org). This library includes a FEM program (Finite Element Method) for the study of the mechanical and hydraulic behaviour of soils, rocks, geotextiles, and granular materials, either fully or partially saturated.

MechSys includes structures for efficient linear algebra, numerical methods, tensor calculus, material modelling, optimization, mesh generation, and friendly user interface (with CAD - Computer Aided Design and GUI - Graphical User Interface).

I have also experience with a range of commercial computer tools such as SAP2000, Plaxis, FLAC, UDEC, GeoSlope, SoilVision, ABAQUS, Midas/GTS, Phase2D, RocSupport, RocLab, and others.

Lately, I have been supervising 3 PhD students, 1 MSc student, and 3 research associates (post-docs) at the Golder Geomechanics Centre in Australia.

The courses I used to teach and am currently teaching include:

Journals Papers

Sofware

Table 1: Free software with open source (GNU/Linux, Mac OS X, MS Windows)

FAILPLOT Failure criteria and yield surfaces visualization tool. Didactic tool for the visualization of common failure criteria and yield surfaces in the Haigh-Westergaard principal stress space MechSys.
LABTESTSIM Laboratory test simulator - mechanical behaviour. Tool for the simulation of the local mechanical behaviour of materials via continuum mechanics. Eight constitutive models for soils, including for unsaturated soils are available MechSys.
PRMSEEK Constitutive parameters optimizer. This program finds the best constitutive parameters for constitutive models basing on a large set of experimental data from mechanical tests, such as the true triaxial and hollow-cylinder tests MechSys.
MECHSYS Open library for mechanical systems. C++ library for the efficient implementation of computational tools for the study of the continuum mechanical behaviour of bodies and structures http://mechsys.nongnu.org MechSys.
MSYS/FEM Parallel 3D finite element program with soil-water coupling. This tool has a non-linear solver which is able to solve quasi-static soil-water coupled problems based on the mechanics for unsaturated soils http://mechsys.nongnu.org MechSys.
MSYS/MPM Material Point Method for Geotechnical Engineering. Tool for large deformation analyses of geotechnical problems with or without particle separation such as in EIPFC (explosions, impact, penetration, fracture, contact)
MSYS/DEM Discrete Element Method for Geotechnical Engineering. Tool for large deformation analyses of geotechnical problems
MSYS/LAEXPR Matrix/vector expressions template library C++ library for the efficient implementation of linear algebra via the expressions template technique. Operations between matrices and vectors are available using operator overloading, however, free from temporary structures MechSys.
SGA Simple genetic algorithms in parallel library. C++ classes for the implementation of genetic algorithm optimisers SGA.
TENSORS Tensor analysis library. C++ library for the efficient implementation of tensor analyses. This theory is strongly used in constitutive modelling of materials. This library uses direct, tensorial, or Gibbs notation resulting in a convenient methodology for the implementation of constitutive equations Tensors.

Civil Engineering Design

Table 2: Designs I have developed - Architecture, foundations, structures, and installations (water supply, sewage, fire protection, electricity, telephone, and data network)

Year Name Purposes Storeys Area Structure
2006 Justino Ribeiro Bldg. Apartments 4 1406.96 m2 Reinf. Concrete
2000 Santa Isabel Bldg. Apartments 4 720.00 m2 Reinf. Concrete
1999 Aphonsiano College Educational 7 8995.14 m2 Reinf. Concrete
1999 Mrs. Madalena Residential 2 250.00 m2 Reinf. Concrete
1999 Euro Centre English Course Educational 2 631.20 m2 Reinf. Concrete
1997 Ms. Elzites Residential 1 185.42 m2 Reinf. Concrete
1997 Mr. Adriano Residential 1 274.48 m2 Reinf. Concrete
1996 Mr. Marcos Residential 2 298.40 m22 Reinf. Concrete

Teaching 2009/1

Current research -- Geomechanics

Among engineering geologists, mining engineers, civil engineers, and other engineering sciences the uniform term of GEOMECHANICS is well known and accepted. It distinguishes the science of displacements and forces in the technically relevant part of the crust of Earth. The range of application of geomechanics is therefore considerable (see e.g., Gudehus, 1977).

A: GeoFEM Project -- Finite Element Method in Geomechanics

Geomechanics is more complex than other branches of technical mechanics, for instance fluid mechanics or the theory of elasticity, because of the highly non-linear and heterogeneous nature of geo-materials. Very often, the solution based on a rational mathematical representation of problems in geomechanics can not be easily found. Therefore, a numerical approach has to be employed, specially if one requires information on safety and efficiency of a geo-structure. The finite element method (FEM) is a numerical tool that can provide reasonable accurate approximations to these problems in an efficient manner.

Several FE programs, both commercial or not are available.

Among free software with open source there are:

Among well known commercial ones there are:

MechSys (http://mechsys.nongnu.org) is a powerful tool; it includes programs based on numerical methods but is also a library for generic computational mechanics. MechSys/FEM is a powerful FE package including a friendly graphical interface (GUI based on Blender www.blender.org) with CAD and mesh generators (Triangle http://www.cs.cmu.edu/~quake/triangle.html and TetGen http://tetgen.berlios.de/). Visualization of specific variables of structural mechanics is also available through this interface (GUI) and advanced visualization is seamless integrated with ParaView (http://www.paraview.org). Internally, MechSys/FEM implements advanced numerical techniques for the solution of highly non-linear problems including three-phase coupling rendering an efficient, accurate, and easy to use computational environment.

This project involves:

Project examples:

Requirements:

First steps:

Tools:

Advanced steps:

B: GeoModel Project -- Geomaterials Modelling

Geomaterials such as sands, clay, rock, and concrete are involved in a very large number of engineering applications (geotechnical, structural, petroleum, environmental, etc) and have for this reason been the subject of much research. Common to all geomaterials is their porous structure comprising a solid (often called the matrix) permeated by a network of pores which may be filled with a fluid (liquid or gas). The properties of interest usually revolve around their response to mechanical loading and their ability to conduct fluids. Other important aspects include heat conduction, wave propagation and the diffusion of various substances through the pore network.

Project examples:

Tools:

C: CFDFire Project -- Computational Fluid Dynamics for Fire Simulation

Fires in tunnels are a major hazard to human life and can cause costly damage to surrounding infrastructure. Limited escape facilities and difficulties encountered by intervention forces gaining access to an emergency in a tunnel demand extensive safety arrangements which must also be complementary and mutually coordinated.

Tunnels and underground transport facilities are important means of communication, not only in terms of shorter journeys but increasingly for consideration of the local population and the environment. Generally speaking, important underground transport links are expected to be available without any restrictions and to operate smoothly round the clock. Interruptions due to accidents, technical malfunctions or maintenance work quickly cause traffic jams and delays, and figure in transport policy statistics as economic losses.

Tools:

Project examples

D: AIEng Project -- Optimization in Engineering using Artificial Intelligence

Many optimization problems from the industrial engineering world, in particular the manufacturing systems, are very complex in natura and quite hard to be solved by conventional optimization techniques. Since the 1960s, there has been an increasing interest in imitating living beings to solve such problems. Generally, by simulating the natural process results in stochastic optimization techniques such as those called evolutionary algorithms. One subset of these algorithms is the genetic algorithms.

Recently, genetic algorithms have received considerable attention regarding their potential as an optimization technique for complex problems and have been successfully applied in the area of industrial engineering. The well-known applications include scheduling and sequencing, reliability design, vehicle routing and scheduling, group technology, facility layout and location, transportation, and many others (see e.g Gen and Cheng, 1997).

Project examples:

Tools: