This paper focuses on the application of a beam-particle model to study the failure of concrete under complex loading. The formulation of the model is based both on lattice models and discrete elements models in order to capture cohesion, failure and frictional contact of the crack surfaces. To correctly describe the elastic phase, the peak load and the post-peak phase, the failure criteria is discussed and heterogeneities are introduced. The calibration of this model is detailed and illustrated. Finally, several test cases are analysed in order to validate the model.

International audienceThe description of damaged zones in large scale structures can nowadays be assessed by means of a finite element approach using an appropriate damage model. Nevertheless, a fine description of cracking (crack pattern, crack length, crack opening, crack tortuosity) is of primary importance to satisfy new requirements in design codes, especially when dealing with structure durability. In this paper, a computational strategy to quantify cracking at structural case is proposed. A continuous damage model is used to perform a full resolution at the global scale. Then, a reanalysis (implemented as a post-treatment) of the damaged zones is performed at the local scale with a discrete element model. A non-intrusive and decoupled numerical scheme allows for a two-scale analysis using each mechanical model (continuous as well as discrete) within its more efficient level. 2D and 3D test cases will be treated to illustrate the non-intrusive global/local analysis

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International audienceThe study of a reinforced concrete beam tested under four-point bending is proposed in this article. An analysis of the behaviour of this beam from the global response down to local information such as cracking is performed. In order to describe the progressive degradation of the beam, a damage model is used, associated to a stress-based non-local regularisation method. A post-treatment of the finite element analysis is then performed to characterise the cracking pattern (crack spacing and crack opening). In this article, two different methods of post-treatment are compared: the topological search and continuous/discontinuous crack opening and the global/local analysis. Results show the capability of both methods to give a good estimation of cracking. Finally, the main advantages and drawbacks of both methods are underlined