Ansys is a powerful commercial software suite, so there isn't a single free program that offers all its functionalities. However, depending on your specific needs, here are some free and open-source options that can handle various aspects of structural analysis similar to Ansys:
General Structural Analysis:
- CalculiX: This open-source project provides a complete FEA (Finite Element Analysis) solution with pre/post-processing capabilities and a built-in solver. It's a good option for general linear structural analysis. (https://www.dhondt.de/)
- Elmer/ElmerGrid: Elmer is an open-source multiphysics solver with modules for structural mechanics. ElmerGrid is a separate mesh generator often used with Elmer. This combination allows for complex simulations, but requires more technical expertise. ([invalid URL removed])
- Salome with Code_Aster: Salome is an open-source pre/post-processing platform compatible with various solvers, including Code_Aster, which focuses on structural analysis. This option offers good flexibility but might require learning multiple tools. (https://old.salome-platform.org/)