A 3D surface and volumetric mesh generator for MATLAB/Octave
OpenNum lets you distribute solvers with a nice graphical interface
PySCeS Constraint Based Modelling
Biomolecular electrostatics software
A multi-modeling and simulation environment to study complex systems
Fortran library with the Abaqus user material subroutines UMAT/VUMAT
GMES is a free Python package for FDTD electromagnetic simulations.
A FDTD solver for electromagnetic wave simulations on a GPU cluster
Advanced numerical instruments: adaptive meshing, FE methods, solvers
A Library for Interactive Modelling and Visualisation
A collection of lecture notes and accompanying code on micromechanics
LIME is a software tool for creating multiphysics simulation codes.
A finite element solver using state-of-the-art programming techniques.