OpenSEES

OpenSEES (Open System for Earthquake Engineering Simulation) is an open-source platform used to model structural and geotechnical systems under seismic loads. Researchers script structural elements, materials, and dynamic loads, then solve for displacements, stresses, or damage states. Advanced soil-structure interaction models are possible. While it lacks a built-in GUI, add-ons exist. OpenSEES is widely adopted in civil engineering academia for earthquake resilience studies and structural performance analyses.