THM-MPM with compressible fluid published in CMAME

Enhancing dynamic modeling of porous media with compressible fluid: A THM material point method with improved fractional step formulation

Fractional step schemes in MPM usually assume an incompressible pore fluid, which rules out problems such as unsaturated soils and geothermal systems.

We extend the fractional step MPM to include fluid compressibility and thermal effects, and introduce a node-based implicit scheme for the intermediate variables that greatly improves efficiency while keeping the method stable.

The study shows that fluid compressibility is essential for capturing pressure shock waves under mechanical or thermal loading, that the semi-implicit scheme matches the accuracy of explicit schemes with better stability, and that the framework extends naturally to three-phase porous media.