CalculiX

CalculiX is an open-source finite element analysis (FEA) software package for structural mechanics and heat transfer. It combines a solver with pre- and post-processing utilities, providing a free alternative to proprietary FEA packages. CalculiX accepts a text input file and uses an Abaqus-like syntax to describe meshes, materials, boundary conditions, and load cases, which can be prepared with the integrated pre- and post-processing tools.

The solver component, ccx (CalculiX CrunchiX), computes the finite element equations for static, dynamic, and transient problems. A companion pre/post processor, CGX, handles model creation, mesh manipulation, and results visualization, with optional use of external viewers such as ParaView. The typical workflow involves generating a model in CGX, running the solver via the ccx executable, and examining results in CGX or a viewer.

CalculiX supports linear and nonlinear structural analysis, geometric and material nonlinearities, contact mechanics, and thermo-mechanical coupling. It provides various element types (plane, shell, and solid elements) and material models suitable for engineering simulations, including time-dependent loading, large deformations, and energy balance checks. The open design encourages scripting and integration with other tools.

CalculiX is distributed under a free software license and has been developed by a community of researchers and practitioners. It is available for multiple platforms, primarily Unix-like systems, with ongoing efforts to improve compatibility and installation on additional environments.