Modeling mode-I fracture process in concrete at meso-scale: Computational aspects of lattice model and a comparison between results of two dimensional lattice simulation and acoustic emission measurements

摘要

This article reports a comparative study on the Acoustic Emission (AE) measurements and Two-Dimensional (2D) lattice simulation results related to mode-I fracture process in plain cement concrete Three Point Bend (TPB) specimen. Computational aspects and programming details of lattice modeling have been discussed. AE based b-values were compared with lattice modelling results. The meso-scale modeling of the heterogeneous Timoshenko Beam (TB) lattice and its Finite Element Analysis (FEA) was performed using programs developed by the authors in MATLAB and FORTRAN respectively. A tensile stress based fracture law was used to remove the beam elements reaching the threshold stress values. Since, the removal of an element from the lattice network can be considered similar to a 'virtual' AE event, the number of failed elements in lattice network was compared with AE parameters recorded during the experiment. An attempt was also made to study the trend of the cumulative number of failed elements in lattice model with the trend of the b-value variation with load level. The trend of cumulative fractured beam elements observed from lattice simulation reflected the trend in AE recorded. By considering softening of cement matrix at element level, the simulation results seem to give better correlation with AE recorded.