dynamique des systèmes

The laboratory has two platforms dedicated to numerical developments:

  • Nessy (NEtwork Solver SYstem)
  • SDT (Structural Dynamics Toolbox) / OpenFem

Nessy (NEtwork Solver SYstem) :

Members involved:

Gérard Coffignal, Philippe Lorong, Lounes Illoul, Christophe Gengembre


Nessy propose un cadre de développement pour résoudre des problèmes non-linéaires de grande taille par l'utilisation du calcul parallèle à gros grain. Elle est destinée à intégrer et tester de nouvelles méthodes de modélisation et de simulation numériques au sein du laboratoire. Une première version de nessy a vu le jour au cours de l’année 1996, mais des développements plus anciens en font partie. Parmi les applications implémentées dans Nessy, nous pouvons citer : la CNEM (Constrained Natural Element Method), l'Usinage Macroscopique, des Elements finis spécifiques.

Nessy proposes a development framework for solving large nonlinear problems by using coarse-grained parallel computing. It is intended to integrate and test new methods of numerical modeling and simulation within the laboratory. A first version of nessy was released in 1996, but older developments are included. You will find CNEM (Constrained Natural Element Method), and Macroscopic Machining, specific Finite Elements among the applications implemented in Nessy.

Nessy currently runs on Mac OS X (PowerPC and MacIntel), Linux, and other Unix. Nessy currently contains over 4000 Fortran 77 routines and some parts are written in C or C++.

We have recently encapsulated a part of Nessy in an object application in Python language. This encapsulation allows to graphically parameterize the input data as well as to automatically analyze the results of Nessy instances executed in parallel and/or in series.

SDTools and openFEM :

Members involved:

Etiennes Balmes, Jean-Philippe Bianchi, Guillaume Vermot des Roches


The Etiennes Balmes' SDTools team joined the PIMM laboratory in September 2008. Its developments is based on the Matlab environment for which it proposes 2 software in evolution:

  • OpenFEM (SDTools/INRIA): a software distributed freely under GNU LGPL license. It is a general purpose multiphysics finite element code.
  • SDT (SDTools) : a commercial toolbox that provides tools for experimental modal analysis and finite element modeling for vibration problems, and optimized solvers for large sizes.

Other numerical simulation activities at PIMM:

The following calculation codes are used in the lab:

  • COMSOL Multiphysics
  • ABAQUS 6.7 to 6.9 (finite element calculations)
  • Materials Studio (molecular dynamics simulations)

Fortran is sometimes used to in order tp enrich Abaqus.

Hardware for SHM:

Workstations dedicated to numerical computation:

  • DELL workstation, Intel Xeon ES 2630 v2 at 2.60 GHz (2 processors of 6 cores/12 threads, 15 MB cache per proc.), 128 GB for RAM, 1.8 TB.
  • i7 server with a Tesla GPU card under Linux: the former LMSP lab acquired at the end of 2009 a tower with an Intel i7 processor (4 cores at 2.67 GHz) and a Tesla GPU card with 250 cores at 1.1 GHz.
  • HP tower under Linux containing 2 Intel Xeon processors at 3.2 GHz. Cache memory per processor: 2Mb RAM memory: 8Gb.
  • Transtec tower under Linux, dual processor, 4 Opteron cores, 16 GB RAM.
  • Dell Tower under Linux containing an Intel Xeon W3530 2.80 at 3.06 GHz (Turbo) (4 cores, 8 threads). Cache memory: 8 MB, RAM: 6 GB.