Force and Displacement Mixed Approach for Interfaces Connecting Rigid Bodies

In this contribution, a simple mixed approach that considers as independent variables both displacements and interface stresses between rigid blocks is described. The work aims to propose an alternative computational tool for studying the static equilibrium of rigid blocks connected by elastic interfaces and subjected to in-plane actions, representing simple assemblies such as brittle or granular materials, and with particular reference to mortar and/or dry-jointed masonry. Assuming a piecewise constant distribution of normal and shear stresses along the generic interface, the numerical model converges to the typical stiffness matrix of the interface. The proposed tool is here applied to in-plane linear static analysis of rigid bodies connected by elastic interfaces, but will allow a further improvement for performing analyses in case of out-of-plane actions and also accounting for material nonlinearity.