Numerical Study of Concrete Dynamic Splitting Based on 3D Realistic Aggregate Mesoscopic Model

Abstract

In mesoscopic scale, concrete is regarded as a heterogeneous three-phase material composed of mortar, aggregate and interfacial transition zone (ITZ). The effect of mesoscopic structure on the mechanical behaviors of concrete should be paid more attention. The fractal characteristics of aggregate were calculated, then the geometric models of aggregate were reconstructed by using fractal Brownian motion. Based on the random distribution of aggregates, the concrete mesoscopic structure model was established. And the numerical model was generated by using grid mapping technology. The dynamic compression experiments of concrete under Split Hopkinson Pressure Bar (SHPB) loading verify the reliability and validity of the mesoscopic structural model and the parameters of the constitutive model. Based on these, a numerical study of concrete under dynamic splitting is carried out. By changing the parameters of the constitutive model, the effects of tensile strengths of aggregate, mortar and ITZ on the dynamic tensile strength of concrete are discussed. The results show that the dynamic failure of specimen usually occurs at the interfacial transition zone, then extends to the mortar, and the aggregates rarely fail. However, the increase of strain rate intensifies this process. When the strain rate increases from 72.93 s−1 to 186.51 s−1, a large number of aggregate elements are deleted due to reaching the failure threshold. The variation of tensile strengths of each phase component have the same effect on the dynamic tensile strength and energy of concrete. The dynamic tensile strength and energy of concrete are most affected by the tensile strength of mortar, following by the ITZ, but the tensile strength of aggregate has almost no effect.

Experimental and Numerical Study on Interface Bond Strength and Anchorage Performance of Steel Bars within Prefabricated Concrete

“…Much numerical research has been carried out on the stochastic character of concrete [16][17][18][19][20][21]. Concrete is a primary construction material composed of cement and aggregates and the geometry and distribution of aggregates significantly affect the interface bond performance of the concrete structure.…”

Effect of nano-SiO2 and nano-CaCO3 on the static and dynamic properties of concrete

“…The peak strain refers to the strain corresponding to the peak stress of concrete under dynamic load. At this point, the concrete is at the critical value for unstable crack propagation, that is, any further loading will damage the concrete and make it unable to bear effective load any more 30 . Therefore, peak strain is an important parameter representing the compressive deformability of concrete under dynamic load.…”

“…Most of above studies focused on static mechanical properties of nano-SiO 2 modified concrete and nano-CaCO 3 modified concrete 21 , 22 , that is, there are few studies concerning relevant dynamic mechanical properties. However, besides static load, many concrete structures will inevitably be threatened by dynamic loads 23 , 24 , e.g., impact, explosion and etc. during their service period 25 – 27 .…”

Experimental and numerical research of crack propagation process and energy dissipation law of grouting specimens under radial impact load

“…The split Hopkinson pressure bar (SHPB) system has been commonly used in dynamic compression, splitting, and fracture testing of the materials in a dynamic load test (Dai et al, 2010;Chen et al, 2014;Liao et al, 2016;Zhu et al, 2022). Most previous experimental studies have focused on strain rate effects (Liu et al, 2019;Yu et al, 2021).…”