Fluid-Structure Interaction Analysis with Radioss and AcuSolve

Note: Support for Direct Coupled Fluid-Structure Interaction (DC-FSI) Radioss and AcuSolve has been discontinued. It is now recommended to use OptiStruct coupled with AcuSolve as described in Fluid-Structure Interaction in the OptiStruct User Guide.
Radioss and AcuSolve are fully-integrated to perform a Direct Coupled Fluid-Structure Interaction (DC-FSI) Analysis based on a partitioned staggered approach. Radioss and AcuSolve are both time domain simulation codes that break the coupled simulation into a number of time steps. Because the governing equations of both Radioss and AcuSolve are nonlinear, sub-iterations are typically required within each time step. At each sub-iteration of FSI analysis, the fluid tractions in AcuSolve are converted into nodal forces which are then transferred to the structural interface mesh of Radioss. These forces are used to calculate the deformation of the structure using Radioss. Note that in addition to the load from the fluid flow tractions, additional structural loads can also be applied. The resulting deformed shape of structure is passed back to AcuSolve as the new fluid boundary. This FSI cycle is shown below in Figure 1.

Figure 1. Direct-Coupled Fluid-Structure Interaction (DC-FSI) Cycle

Target Applications

The DC-FSI capability aims at simulations of compliant structural response to fluid flow and its complex interrelationship. This capability is particularly suited for problems exhibiting nonlinear structural response. It may also be used for linear structural response; however, for linear structural response the P-FSI solution offered by AcuSolve may be more effective in solving the linearized structural response with the nonlinear flow solution. For further information on the P-FSI method, refer to the AcuSolve Command Reference Manual. Most Radioss features including nonlinear materials, nonlinear geometric effects, and contact are available for use. The interface domain can be modeled with solid, shell, and beam elements. Most of the features in AcuSolve can be used in DC-FSI simulations. These features may include, namely laminar or turbulent flow, heat transfer, a rich set of material options, free-surface and multi-species driven flows. The moving boundary problems are modeled using Arbitrary Lagrangian-Eulerian (ALE) and sliding mesh technologies. For further details, consult the AcuSolve Command Reference Manual.

Primary applications targeted by this capability include:
  • Automotive: Hydraulically damped rubber mounts, door seals, shock absorbers, design of valves and rubber diaphragms and antilock braking systems
  • Oil/Gas: Long marine risers, moorings, free spans and drilling risers
  • Aerospace: Wing aero-elasticity, UAV and MAV
  • Wind turbine: Large deformation of blades
  • Consumer Goods: design and packaging
  • Bio-medical