The analysis of the dynamic nonlinear behavior of masonry structures is a complex task. The importance of intensifying the knowledge of these structures is essential for the preservation of the cultural heritage, considering the massive presence of peculiar existing buildings in the European area with high seismic hazard, and for the evaluation of new structures against strong actions. In this framework, the relevance of the present work is to propose a new hybrid FEM-DEM strategy, which combines the advantages of the classical finite and discrete element methods in an optimized tool. The present paper illustrates the capabilities of the hybrid model to reproduce the real complex behavior of masonry during experimental tests and seismic actions. The numerical implementation has been made in the open-source LMGC90 code. In this hybrid approach, anisotropic damageable deformable blocks interact each other through contact joints governed by frictional cohesive behaviors. The DEM framework permits large displacements, rotations, and complete detachments of the blocks, which are neglected with FEM models. The combined hybrid FEM-DEM approach allows to deal efficiently with the numerical assessment of complex masonry structures. Thus, a comparative work is developed with a focus on the advantages and disadvantages of the hybrid model with respect to usual micro- and macro-modeling (aka block based model or continuous homogeneous model). The calibration process of the mechanical material characteristics was based on the experimental tests on masonry specimens (triplet test, axial, and diagonal compression tests), which were numerically simulated for each modeling technique. Finally, the main application performed in this work concern the seismic assessment of a masonry cross vault. The main aspect of the numerical results concerns the ability of this approach in providing realistic prediction of failure mechanisms, which are relevant for retrofitting works, according to the real cracking pattern, thus following the real stereotomy of the masonry and considering large deformations.

KEYWORDS: Masonry, Anisotropic damage mechanics, Non-smooth contact dynamics, Cohesive zone model, Hybrid FEM-DEM model