A Three-Dimensional Structural Finite Element Program

CalculiX Finite Element Models can be build, calculated and
post-processed. The pre- and post-processor is an interactive 3D-tool 
using the openGL API. 

Notice: The authors acknowledge that naming conventions and input style 
formats for CalculiX are based on those used by ABAQUS, a proprietary, 
general purpose finite element code developed and supported by Hibbitt, 
Karlsson & Sorensen, Inc (HKS) and are used with kind permission from HKS. 
Results obtained from CalculiX are in no way connected to ABAQUS.

WWW: http://www.calculix.de/

note: By default the single-threaded solver is used, this can be changed 
by setting the CCX_NPROC environment variable with the number of 
processors you want to use.