FEM-DEM simulation of Uniaxial Compressive Strength (UCS) laboratory tests

Abstract

Finite/discrete element methods (FDEM) are hybrid numerical models that use algorithms to analyze the transition from continuous to discontinuous. This type of formulation allows modeling physical laboratory tests with greater proximity to reality. This article proposes to simulate the average behavior of a uniaxial compression test campaign. The tests were modeled and calibrated based on the strength and the fracture pattern using Geomechanica Inc. Irazu two-dimensional software. The simulated results were analyzed by the mean standard deviation of approximately 3000 elements in the middle third of the model, the same region where the clip gages are located in the physical test. The obtained results show that FDEM can replicate the laboratory test with great similarity.

FEM-DEM simulation of Brazilian Tensile Strength (BTS) laboratory tests

“…The platen displacement velocity, the viscous damping factor, and the contact penalties were defined in a uniaxial compression test model discussed by Oliveira et al (2020). The value for the platen velocity used in the simulation of the BTS was 0.03 m /s.…”

“…The contact penalties were modeled (Stefanizzi et al, 2009). in order to find the lowest standard deviation for principal stress (σ1) in the uniaxial compression test (Oliveira et al 2020). The normal and tangential contact penalties for the fracture were in the order of 100 times greater than the modulus of elasticity.…”

“…Table 1 summarizes the properties of the meta-andesite and the platens which are discussed in more detail by Oliveira et al (2020). The platen resistance was considered constant equal to 200 MPa, significantly higher than the specimen resistance.…”

“…The present article aims to calibrate and simulate the Brazilian Tensile Strength (BTS) laboratory tests using the hybrid numerical modeling -Finite Elements/ Discrete Element Method. Oliveira et al (2020) performed the initial calibration of the meta-andesite geomechanical parameters and a simulation of a uniaxial compression test. Experimental tests of the indirect tensile strength (BTS) in metaandesite were made using the International Society of Rock Mechanics suggestions (ISRM, 1978).…”

“…Tatone and Grasselli (2015) suggest the steps for calibrating the energies of the two-mode fracture. The other variables of the model such as discretization element size, platen velocity, viscous damping and contact penalties are discussed by Oliveira et al (2020) in their calibration research of the uniaxial compression test of the same material.…”