The 2-way FEM simulation of the HDR blowdown. The simulation is performed by coupling in the ADINA-FEM code with the potential based fluid and the structure. Here, the structure is non-linear, with sliding contact at the core barrel flange, pre-stressed bolts, and plastic material model, and also the potential based fluid is non-linear because the subsonic variant is used. Hence, the pressure at the break location can be used as boundary condition. The model is initialized to full pressure before the start of the blowdown transient, since the non-linear model requires that all loads are applied simultaneously.

The structural displacements are magnified 500X for visualization purposes. The Bathe time integration method in ADINA displays excellent transient fidelity and stability throughout the simulation.

For details, see the article On blowdown analysis with efficient and reliable direct time integration methods for wave propagation and fluid-structure-interaction response.

We made a study earlier, see: Accurate Implicit Time Integration in Nonlinear Dynamic Analysis