Numerical study of the semi-circular bend dynamic fracture toughness test using discrete element models

Guo-jie, Zhao; Kazerani, Tohid; Man, Ke; Gao, Ming; Zhao, Jian

doi:10.1007/s11431-015-5887-z

Cited by 19 publications

(5 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, DEM works quite well in the dynamic rock fragmentation and fracture because of the discontinuum assumption. The examples of using this method can be found, for example, in refs [16,19,44]. Combining FEM and DEM provides a unique opportunity to have the features of continuum and discontinuum techniques in one code.…”

mentioning

confidence: 99%

A numerical and experimental study on the tensile behavior of plasma shocked granite under dynamic loading

Mardoukhi

Saksala²,

Hokka³

et al. 2017

RakMek

View full text Add to dashboard Cite

Summary. This paper presents a numerical and experimental study on the mechanical behavior of plasma shocked rock. The dynamic tensile behavior of plasma shock treated Balmoral Red granite was studied under dynamic loading using the Brazilian disc test and the Split Hopkinson Pressure Bar device. Different heat shocks were produced on the Brazilian disc samples by moving the plasma gun over the sample at different speeds. Microscopy clearly showed that as the duration of the thermal shock increases, the number of the surface cracks and their complexity increases (quantified here as the fractal dimension of the crack patterns) and the area of the damaged surface grows larger as well. At the highest thermal shock duration of 0.80 seconds the tensile strength of the Brazilian disc sample drops by approximately 20%. In the numerical simulations of the dynamic Brazilian disc test, this decrease in tensile strength was reproduced by modeling the plasma shock induced damage using the embedded discontinuity finite element method. The damage caused by the plasma shock was modeled by two methods, namely by pre-embedded discontinuity populations with zero strength and by assuming that the rock strength is lowered and conform to the Weibull distribution. This paper presents a quantitative assessment of the effects of the heat shock, the surface microstructure and mechanical behavior of the studied rock, and a promising numerical model to account for the pre-existing crack distributions in a rock material.

show abstract

mentioning

confidence: 99%

A numerical and experimental study on the tensile behavior of plasma shocked granite under dynamic loading

Mardoukhi

Saksala²,

Hokka³

et al. 2017

RakMek

View full text Add to dashboard Cite

show abstract

“…However, to simulate discontinuous behavior and large displacement of rock, it is more promising to use discontinuum-based methods. These methods, including particle flow code (PFC) (Li et al 2014;Li et al 2018;Xu et al 2016), universal distinct element code (UDEC) (Yan et al 2012), and distinct lattice spring model (DLSM) (Zhao et al 2014;Zhao et al 2015), have been widely used for the simulation of rock dynamics. In the realm of investigating the dynamic mechanical characteristics of rock, hybrid continuum-discontinuum approaches have gained prominence.…”

Section: Introductionmentioning

confidence: 99%

“…However, Zhao et al (2014) found that the heterogeneity or microstructure of rock only contributes limited influence to the rate dependency. To reproduce the whole rate dependency, one possible solution is to implement a rate-dependent constitutive model that establishes the relationship between loading rates and the strength parameters, which has already been used in UDEC (Zhao et al 2015), DLSM (Kazerani et al 2010) and other methods (Zhang et al 2022). However, there is insufficient research to directly validate this method with SHPB experiments.…”

Section: Introductionmentioning

confidence: 99%

Quantitative investigation of rock dynamic failure using Voronoi-based discontinuous deformation analysis

Zhang,

Liu

et al. 2023

Preprint

View full text Add to dashboard Cite

Dynamic failure widely exists in rock engineering, such as excavation, blasting, and rockburst. However, the quantitative measurement of the dynamic damage process using experimental methods remains a challenge. In this study, a SHPB modeling technique is established based on Voronoi-based DDA to study the damage evolution of Fangshan granite under dynamic loading. The assessment of cracking along the artificial joints among Voronoi sub-blocks is conducted by employing the modified contact constitutive law. A calibration procedure has been implemented to investigate the rock dynamic properties quantitatively. The dispersion and damping effect can be effectively eliminated by regular discretization in SHPB bars, based on which the dynamic stress equilibrium can be satisfied. To reproduce the loading rate effect of the dynamic compressive strength, which has been observed in the experiment, a modification strategy considering the influence of the rate effect on the strength meso-parameters is proposed. Using this strategy, the peak stresses of the transmitted waves predicted by DDA match well with those obtained from experiments conducted at different loading rates. The simulation results show that more microcracks are generated and the proportion of tensile cracks decreases as the loading rate increases. Furthermore, the dynamic mechanical behavior and fracturing process have also been discussed and compared with the experiments. The results show that the established SHPB system is a powerful tool for quantitative analysis of rock dynamics problems and is capable of handling more complex problems in the future.

show abstract

“…In the field of theoretical and numerical research, Lim et al [17] proposed the calculation method of stress intensity factor (SIF) for notched SCB specimens in 1993, which provided a means for the study of fracture parameters in mixed mode. Zhao et al [18] used the discrete element model to numerically simulate the dynamic fracture toughness of the SCB specimen with bottom groove. Eftekhari et al [19] discussed the fracture properties of notched SCB specimens under mixed mode loading using the extended finite element method.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of 3-D Internal Crack Propagation in Rock under Semi-circle Bending

Zhang

Gu²

2022

Period. Polytech. Civil Eng.

View full text Add to dashboard Cite

Semi-circle bending (SCB) test is an important test in the field of rock fracture. In order to investigate the propagation process of 3-D internal cracks under semi-circular bending, numerical simulations of SCB specimens were carried out based on the finite element method and adaptive mesh technique. The results show that the numerical simulation results of this method are in good agreement with the previous laboratory test. The symmetrical loading model belongs to the pure I loading where the value of KI is positively related to the bottom load span S/R. The asymmetric loading model belongs to mix-mode loading. With the increase of unilateral load span S2/R, there is a decline and then a rise of the value of SIF at the same point at the crack tip. The S2/R is an important factor affecting the mechanical properties of rock specimens. The crack propagation path was obtained based on the maximum tensile stress (MTS) criterion. In-plane propagation of the internal crack in the symmetrically loading model leads to failure of the specimen. Wing propagation of the internal crack in the asymmetrically loading model causes the specimen to fracture into two asymmetrical parts. Quantitative analysis of the internal crack propagation of the symmetrical loading model shows that the growth rate of the lower end of the crack is the largest, and the upper end of the crack is the smallest. The above results can provide a reference for the research on the propagation of 3-D internal cracks of SCB specimens.

show abstract

Numerical study of the semi-circular bend dynamic fracture toughness test using discrete element models

Cited by 19 publications

References 23 publications

A numerical and experimental study on the tensile behavior of plasma shocked granite under dynamic loading

A numerical and experimental study on the tensile behavior of plasma shocked granite under dynamic loading

Quantitative investigation of rock dynamic failure using Voronoi-based discontinuous deformation analysis

Numerical Simulation of 3-D Internal Crack Propagation in Rock under Semi-circle Bending

Contact Info

Product

Resources

About