Meso-scale modeling of size effect in eccentrically-loaded squared CFST columns: Influence of eccentricity and confinement effect

Meso‐scale modeling of size effect on pure torsional failure of concrete‐filled steel tubular columns

“…The determination method of mechanical parameters of the ITZ is as follows: first, the mechanical parameters of mortar matrix are reduced by 70%-85%, and then different values are selected in this interval to determine the mechanical parameters of ITZ by repeated trial calculation. 21,35 A 3D microscopic numerical model of standard cubic concrete test block was established. Through repeated trial calculation of mechanical parameters in the ITZ, when each mechanical parameter is the same as in Table 2, the simulated value of concrete compressive strength (54.28 MPa) is consistent with the experimental value (55 MPa), indicating the parameters were reasonable.…”

“…The plastic damage constitutive model applied in the studies 33,34 was used for the constitutive relation of concrete materials. Although the plastic damage is widely applied in the simulation of brittle materials in dynamic load and static load, 24 there are still some limitations, as it cannot accurately describe the mechanical behavior of concrete under the action of a strong constraints 35 . Han et al 17 showed that the plasticity of concrete increased due to the passive constraints of steel tubes.…”

“…Among them, “*” is the measured value of the test, 15 and the “#” in the table is the value of repeated trial calculation, besides, other mechanical parameters are default values. The determination method of mechanical parameters of the ITZ is as follows: first, the mechanical parameters of mortar matrix are reduced by 70%–85%, and then different values are selected in this interval to determine the mechanical parameters of ITZ by repeated trial calculation 21,35 . A 3D microscopic numerical model of standard cubic concrete test block was established.…”

“…Although the plastic damage is widely applied in the simulation of brittle materials in dynamic load and static load, 24 there are still some limitations, as it cannot accurately describe the mechanical behavior of concrete under the action of a strong constraints. 35 Han et al 17 showed that the plasticity of concrete increased due to the passive constraints of steel tubes. By using the finite element method, strength improvement under triaxial loading can be achieved by defining the yield surface and describing the plastic behavior from the equivalent stress-strain relationship of the core concrete.…”