The balance equations of continuum thermodynamics need constitutive equations in
order to solve them under the constraint that the entropy production appearing in
the entropy balance equation must be not negative. This dissipation inequality
represents the second law of thermodynamics. There are two procedures which
exploit the dissipation inequality to obtain constitutive equations which are in
agreement with the second law: the Coleman–Noll and the Liu techniques. Here we
use the Liu technique in the special case in which not all balance equations are
taken into account when exploiting the dissipation inequality. This case is of
interest because often not all balances are known, or only the energy balance is
considered. It is also proved that in this abridged exploitation of the dissipation
inequality, thermodynamic restrictions for the constitutive equations are
obtained, so that these satisfy the second law. These restrictions represent a
smaller class of materials than that obtained when all balances are taken into
account.
Keywords
dissipation inequality, reduced set of balances, abridged
exploitation of the dissipation inequality, second law
exploitation, Coleman–Noll procedure, Liu procedure