The Hydrostatic-Fluid-Mechanical Multiphysics capability allows the user to include the effects of fully enclosed gas- or liquid-filled cavities in his 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.
Plastic bottles used for water coolers must be able to withstand certain severe loadings—specifically, drops from various heights and angles. However, the repeated sterilizations that the bottle must endure slowly reduce the stiffness and strength properties of the polymeric material. To predict the working life of the bottle, the effect of the degraded material properties on the burst strength must be understood.
The hydrostatic fluid-mechanical modeling capability in Abaqus allows for virtual drop testing of any bottle design. The effect of the fluid is easily simulated with the general contact, adaptive remeshing, and equation of state capabilities. Rupture of the bottle can be captured with strain-based dynamic failure models that allow for element deletion.
With the ability to accurately simulate impact loading of water bottles, the need for physical testing is reduced. A greater understanding of how a water bottle performs as its material properties change allows for a better prediction of the bottle's working life. Taken together, these benefits translate into lower production costs and higher quality bottles.