FEM investigation on a flat-jack test setup for local shear characterization in masonry panels

The present investigation concerns the characterization of local in-plane shear strength and failure of masonry panels. A testing geometry has been conceived to experiment the shear response of wall specimens at the laboratory scale by using pressure-controlled flat-jack testing. Before approaching real experimental tests, advanced Finite Element Method (FEM) simulations are carried-out (with the LSDYNA code), with the aim of assessing and optimizing the test geometry as conceived at design stage. Both bricks and mortar are appropriately modeled through the Karagozian & Case (K&C) model. Results show that the test setup configuration looks reasonably well set and put forward first promising benchmark results useful for setup optimization and for later comparison to experimental results, in view of qualitative and quantitative interpretation and consistent identification of local shear structural properties and response of the wall panel. The proposed configuration allows to generate a shear stress state concentrated in the central part of the wall panel, leading ultimately to extensive damage and failure. The resulting damage field predicts mortar fracture in the middle of the wall.