SimpleFEM is a fortran code built for educational purposes. It showcases functional illustrations of the various features of a FEM code: the mesh and its connectivity, the shape functions and their derivatives, the numerical integration, the assembly phase, imposing the boundary conditions, and the system solve.
It is free to download and modify, but beware that it is a starting point for the student, not a fully functional FEM code directly applicable to geodynamic systems. For instance, most of the implemented algorithms are not suited to handle large systems. The code is provided as a tar file. You need to untar it as follows: tar -xvf simplefem.tar You may use any fortran90 compiler, such as ifort, pgf90, gfortran, visual fortran, ...