Modeling fluid–structure interaction by the particle finite element method in OpenSees

• The OpenSees framework is extended for simulation of fluid-structure interaction.
• The implementation uses a Lagrangian formulation of fluid and structure response.
• Verification and validation examples are provided.
• Tsunami loading on a nonlinear RC frame demonstrates modeling capabilities.
• Enables simulation of sequential natural hazards, namely earthquake plus tsunami.

The OpenSees finite element software framework is extended for simulating fluid–structure interaction (FSI) by the particle finite element method (PFEM). At high levels of the framework, new classes handle meshing and interface detection of the fluid and structure domains and implement the fractional step method in order to solve the governing equations of linear momentum and mass conservation. At lower levels of the framework, new finite element and pressure constraint classes assemble fluid contributions to the global system of equations. Verification and validation examples are presented along with a demonstrative example of wave loading on a coastal structure modeled using geometrically nonlinear frame elements with material nonlinear fiber sections. The extension of OpenSees for FSI allows analysts to simulate the complex phenomena of wave loading on structural models as well as the response of these models to sequential natural hazards such as earthquake induced tsunamis.