AbstractThe thermodynamical and variational consistency of cohesive zone models is analyzed in the present contribution. Based on a naive application of the classical Coleman & Noll procedure, it is shown that the second law of thermodynamics is not fulfilled in general. This can even be seen, in case of hyperelastic interfaces. For guaranteeing thermomechanical consistency, additional surface stresses acting at the interface have to be introduced. Based on such findings, a thermomechanically consistent model including dissipative effects is proposed. This model possesses a natural variational structure. More precisely, all state variables can naturally and jointly be computed by minimizing an incrementally defined potential.