A combined finite–discrete numerical model for analysis of masonry structures Hrvoje Smoljanovic´, Z ˇ eljana Nikolic´ ⇑ , Nikolina Z ˇ ivaljic´ University of Split, Faculty of Civil Engineering, Architecture and Geodesy, Split, Matice hrvatske 15, Croatia article info Article history: Received 22 July 2014 Received in revised form 12 November 2014 Accepted 2 February 2015 Available online 11 February 2015 Keywords: Combined finite–discrete element method Masonry structures Orthotropic behaviour Cyclic behaviour abstract This paper presents a new numerical model based on the combined finite–discrete element method for the analysis and prediction of the collapse of masonry structures. The model consists of a new numerical model in a finite element and a new material model in an interface element which simulate the behaviour of the mortar joints and unit-mortar interface. The comparison between the numerical results obtained by this model and the available numerical and experimental results shows high accuracy in predicting the behaviour of the masonry structure through the entire failure mechanism from the con- tinuum to the discontinuum. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction The importance of tracing the structural behaviour beyond the peak and an ability to follow the development of the actual failure mechanism including the transition from the continuum to a discontinuum state in a robust and stable manner has been recognized as vital in modelling of the collapse of masonry structures due to hazardous loading conditions such as intensive seismic excitation, explosions, and missile impact. A number of numerical models have recently been developed for the numerical analysis of masonry structures. The proposed procedures for numerical modelling of masonry structures can be classified into two main groups: continuum and discontinuum based modelling. The most commonly used numerical tool for the analysis of masonry structures is the finite element method where the material is regarded as a fictitious homogeneous orthotropic continuum [1,2]. These models encounter a significant limita- tion to simulate strong discontinuities between different blocks of the masonry. For overcoming these limitations the joint interface elements were developed to model the discontinuities [3,4]. Most of these models cannot take into account the mutual mechanical interaction, finite displacement and rotation including complete detachment such as recognizing new contacts. To overcome this limitation some finite element formulations with large displacements [5] and contact detection have been developed [6]. It is noted that other attractive tools for modelling of masonry structures are based on a discrete element method [7–10]. The common idea in different applications of the discrete element method to masonry structures is the idealization of the material as a discontinuum where joints are modelled as contact surfaces between different blocks. This approach is suitable for modelling different types of non-linear behaviour including large displacements and rotation with complete detachment of blocks. http://dx.doi.org/10.1016/j.engfracmech.2015.02.006 0013-7944/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +385 21 303 323. E-mail address: zeljana.nikolic@gradst.hr (Z ˇ . Nikolic´). Engineering Fracture Mechanics 136 (2015) 1–14 Contents lists available at ScienceDirect Engineering Fracture Mechanics journal homepage: www.elsevier.com/locate/engfracmech