UMATHT Subroutine for hydrogen diffusion - Heat Transfer Analogy
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I have read a few papers that used UMATHT subroutine to model hydrogen distribution in Normal Interstitial Lattice Sites (NILS) and material traps by mapping Fourier's Law and with Laws of Diffusion. The analogy is as follows:
Internal Energy (U) is compared to Total Concentration (C)
Heat Flux (q) is mapped to Mass Flux (J)
Temperature (T) is mapped to Concentration in lattice sites C(L)
Specific Heat (Cp) is mapped to normalised diffusivity
Does anyone have a UMATHT subroutine that does this to share or any standard UMATHT subroutine that can help me understand the various terms DUDT, DUDG, DFDT, DFDG etc.