The Hydrostatic-Fluid-Mechanical Multiphysics capability allows the user to include the effects of fully enclosed gas- or liquid-filled cavities in their model. This is useful for simulating balloons, air bags, seat cushions, athletic shoes, partially filled tanks and other containers, air springs, IV bags, and many other applications that require consideration of the pressure-volume relationship of the enclosure and the energy inside the enclosed fluid. The state equation of the enclosure and the energy in the fluid changes the response of the surrounding structure in significant ways.
Abaqus was the first FEA product to contain an HFM capability introduced first in the early 1990s. Since then, other FEA vendors have added this capability, but the Abaqus functionality remains the market and technology leader in simulating structures containing fluid-filled cavities. Abaqus offers a complete thermo-mechanical capability including multiple linked cavities as well as pressure and volume choking capability in the channels between cavities.