Mesoscale analysis of failure in quasi-brittle materials: comparison between lattice model and acoustic emission data

Abstract

SUMMARYThe purpose of this paper is to analyse the development and the evolution of the fracture process zone during fracture and damage in quasi-brittle materials. A model taking into account the material details at the mesoscale is used to describe the failure process at the scale of the heterogeneities. This model is used to compute histograms of the relative distances between damaged points. These numerical results are compared with experimental data, where the damage evolution is monitored using acoustic emissions. Histograms of the relative distances between damage events in the numerical calculations and acoustic events in the experiments exhibit good agreement. It is shown that the mesoscale model provides relevant information from the point of view of both global responses and the local failure process.

Calibration of nonlocal models for tensile fracture in quasi-brittle heterogeneous materials

“…The nonlocal averaging should describe the finite FPZ experimentally observed in heterogeneous materials. The FPZ in concrete was studied by acoustic emission tests by, for instance, Mihashi et al (1991), Landis (1999), Otsuka and Date (2000), Haidar et al (2005), Muralidhara et al (2010), and Grégoire et al (2015) in which acoustic signals originating from fracture events are spatially located and the strength of the signal is used to differentiate between the magnitude of energy dissipation of events. Other studies include techniques to record the displacements (Cedolin et al, 1987;Wu et al, 2011;Skarżyński et al, 2011) and fracture surface measurements (Lange et al, 1993;Morel et al, 2008;Ponson et al, 2006).…”

“…For these lattice analyses, the heterogeneity of the material is idealised by a single isotropic autocorrelated random field for strength and fracture energy generated by a spectral representation method (Shinozuka and Jan, 1972) used previously for lattice modelling of fracture in Grassl and Bažant (2009) and Grassl and Jirásek (2010). This type of lattice analyses of tensile fracture has been shown to provide qualitatively realistic results (Grassl and Jirásek, 2010;Grassl et al, 2015) and, if calibrated appropriately, can provide a good agreement with fracture experiments (Grassl et al, 2012;Grégoire et al, 2015). In the present study, the modelling approach is only used to investigate the validity of the assumptions of the calibration procedure and a direct comparison with experiments or macroscopic nonlocal modelling results is not carried out.…”

Analysis of Crack Evolution in Concrete through Combined Acoustic Emission Monitoring and Mesoscale Modelling

“…Author, Second B. Author and Third C. Coauthor sensors form a rectangular grid location on one side of (75 x120 mm²) for UN200 beams, (60 x120 mm²) for UN100 beams, (105 x 120 mm²) for SN200 beams and (110 x 120 mm²) for LN200 beams [15].…”

“…Several numerical models were capable to capture important characteristics that emerge in failure process and AE measurements [13,14,15]. A thorough investigation is here performed on this subject by modelling the behaviour of concrete at the mesoscopic scale.…”

Numerical Models for the Assessment of Historical Masonry Structures and Materials, Monitored by Acoustic Emission

“…Different numerical strategies can be adapted to this purpose. The so-called lattice-model allows for a detailed discretization of the microstructure, and acoustic emission events can be related to the rupture of lattice elements or bundle of elements [20]. Alternatively, continuous discretization can be coupled with discontinuities described with the cohesive crack model [21], and crack advancements can be directly related to the occurrence of acoustic emissions.…”