Creep damage evolution equations expressed in terms of dissipated power

Evolution equations of continuum damage mechanics are usually expressed in terms of stresses; some authors introduce other quantities, like strains or elastic energy. The present paper introduces evolution equations expressed in terms of specific dissipated power: for uniaxial stationary creep such equations may simply be derived by some substitutions. It turns out that basing on available experimental data such an approach results in reduction of the number of parameters. Then the extensions to nonstationary creep and to multiaxial states are proposed as hypotheses subject to experimental verification. Finally, an extension to biomechanics is proposed, namely to biological materials subject to recovery. For such materials the damage rate is not necessarily positive: it may also be negative as a result of recovery.