  We develop a novel model, called the ``random-walk shielding-potential
viscosity model'' (RWSP-VM) that introduces the statistics of random-walk ions
and the Debye shielding effect to describe the viscosities of warm dense
metals. The viscosities of several metals with low to high atomic number (Be,
Al, Fe, and U) are calculated using the analytical expression of RWSP-VM.
Additionally, we simulate the viscosities of Fe and Be by employing the
Langevin molecular dynamics (MD) and classical MD, while the MD data for Al and
U are obtained from a previous work. The results of the RWSP-VM are in good
agreement with the MD results, which validates the proposed model. Furthermore,
we compare the RWSP-VM with the one-component plasma model and Yukawa viscosity
model and show that the three models yield results in excellent agreement with
each other in the regime where the RWSP-VM is applicable. These results
indicate that the RWSP-VM is a universal, accurate, and highly efficient model
for calculating the viscosity of metals in the warm dense state. The code of
the proposed RWSP-VM is provided, and it is envisaged that it will have broad
application prospects in numerous fields.
