Implementation of frictional contact conditions in surface to surface, mortar based computational frameworks

A number of recent works have established the mortar technique as an accurate and robust spatial discretization method for contact problems in computational solid mechanics. Since methods based on this idea rely on an integral, non-local representation of the contact operators, their formulation is somewhat more involved than is true for more traditional "point to surface" contact algorithms; in particular, the integral projections have nontrivial linearizations in the fully large deformation context. In this work, we concentrate on another aspect of formulations of this type - definition and implementation of frictional contact operators within the mortar contact framework. Issues associated with frame indifference of frictional tractions and kinematics are discussed, and a numerical demonstration of the technique is given.