Análise em multiescala de flexão de placas de concreto pelo método dos elementos de contorno

Abstract

A BEM multi-scale modelling for analysing the bending problem of concrete plates is presented. The concrete microstructure is represented by the Representative Volume Element (RVE), where the cement paste behaviour is governed by the Mohr-Coulomb criterion while the aggregates are considered elastics. Besides, the porosity of the cement paste is modelled by defining voids into its domain and the microcracking process in the ITZ (Interfacial Transition Zone), is modelled by defining additional cohesive-contact finite elements on interfaces between cement paste and aggregates. To define the microstructure of the RVE and its parameters, a concrete whose experimental compression curve is known is considered. In addition, it was analysed whether it is really necessary to use a complex EVR, with a large number of aggregates and voids, or if the adoption of a simpler RVE can also satisfactorily reproduce the mechanical behaviour of the plates, keeping the volumetric percentage constant. of inclusions and voids. Furthermore, the results are compared with a multiscale formulation where the FEM (Finite Element Method) is considered at the microscale. Finally, it is shown that the proposed model is much faster than the coupled BEM/FEM model.