Balance at a junction among coherent interfaces in continua with substructures

The junction among coherent interfaces separating phases in continua exhibiting material substructure is modeled as a virtual bar endowed by its own measures of interaction (macro- and microstresses and self-forces); balance equations at the junction are derived within a multifield theory. To involve bodies with substructure is not an idle formal exercise; strong anchoring conditions at the boundary rarely allow the existence of smooth solutions. Thus interfaces are more frequent and junctions inevitable if overall substructural order need be preserved. Besides, our development frames together old remarks (e.g., a remark by Gibbs) and new suggestions. Also we have the chance, here, to return to some nontrivial open issues of the general theory.