The characteristics of high speed crack propagation at ultra high loading rate

Zhou, Mao Jun; Li, Yongqiang; Wu, Jian; Yu, Yin; He, Hongliang

doi:10.1016/j.tafmec.2020.102650

Cited by 11 publications

(3 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When K Ⅰ > K Ⅰ c , the crack can grow in a steady manner. It was reported (Zhou et al, 2020) that in the one-dimensional crack growth stage, the average velocity at which the crack growth grows stable is 0.584 folds of the Rayleigh wave velocity, and only a slight degree of velocity oscillation is detected. The velocity of Rayleigh waves is only correlated to the elastic constant of the medium, equalizing 0.862–0.955 folds of the wave velocity of transverse wave in the same medium.…”

Section: Prediction Model For Crack Length In the Scenario Of Blastin...mentioning

confidence: 99%

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Wang

Yang

et al. 2023

Journal of Vibration and Control

View full text Add to dashboard Cite

For fixing the parametric design problem of blasting with water-coupled medium and improving the rock breaking quality, efforts should be made to quantify and examine the blasthole pressure and the explosive crack growth length in the scenario of blasting with water-coupled medium. The water medium was treated as an ideal fluid on the precondition that its flow velocity and internal energy would change continuously with time. Under the elastic wave theory and combining the propagation law of shock wave in water and rock or rock-like medium, the pressure, velocity, and other parameters in relation to shock wave at the interface between explosive and water, in the water medium, and in the peripheral medium after the occurrence of transmission and reflection at the interface between water and hole wall, were subject to theoretical calculations. As a result, the equation for the peak blasthole pressure in the scenarios of explosive and hole wall medium parameters was derived. Further considering the weakening effect of sparse wave on shock wave and the effect of multiple reflections superimposed on shock wave by the hole wall medium, the equation for the attenuation of blasthole pressure as a function of the time constant T was obtained. Next, the prediction model for crack length in the scenario of blasting with water-coupled medium was constructed by the aforementioned equation for calculation of blasthole pressure in the scenario of blasting and according to the model for explosive gas-driven one-dimensional crack growth. Finally, the blasthole pressure and one-dimensional crack length applicable to the explosive and hole wall medium parameter with decoupled coefficients of 1.33, 1.67, 2.00, 2.67, and 3.33 at a given time point were examined by combining the derived equations for theoretical calculations and numerical simulations. Results showed that in the scenario of blasting with water-coupled medium, the blasthole pressure would reduce as the decoupled coefficient η increases, and it is significantly influenced by η, up to 25% even above 50%. Similarly, the crack length would reduce as the decoupled coefficient η increases, but it is slightly influenced by η, only at 15% or so in general.

show abstract

Section: Prediction Model For Crack Length In the Scenario Of Blastin...mentioning

confidence: 99%

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Wang

Yang

et al. 2023

Journal of Vibration and Control

View full text Add to dashboard Cite

show abstract

“…Sun and Zhang used finite element models to study the effect of stress wave pairs on crack angles in the cited reference [18]. Zhou et al [19] specifically studied the crack propagation mechanism of rock as an example material under different loading rates. Zhang et al [20] specifically focused their research on actual coal mining and revealed the damage development process of this material using acoustic methods based on In the past, most studies on excavation or mining have adopted the assumption of rock models without cracks.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Dynamic Propagation Model of Cracks from Different Angles under the Effect of Circular Hole Explosion

et al. 2023

View full text Add to dashboard Cite

A dynamic disturbance will induce cracks around the tunnel in tunnel blasting or shield construction. To investigate the overall stability of cracks with various angles during a fixed borehole (round hole explosion) blasting, models containing an individual crack with different angles were introduced for simulation research. The research set up a thin sheet model with a length of 350 mm and a width of 150 mm, with a 7 mm diameter hole and a pre-existing crack of 75 mm and 5 mm in the middle. The evolution of the stress wave propagation model and the crack propagation model were simulated using the AUTODYN software. And in this study, the theory of stress wave is used to creatively explain the dynamic load under the action of formation and reasons for the danger zone. The results indicate that pre-existing cracks from different angles will have an impact on the blast hole and the new cracks generated around itself. At 45–90°, pre-existing cracks will direct reflected stress waves to promote some cracks around the hole to have faster growth rates than others, and these special cracks with faster growths and longer lengths will more easily connect with the free surface or other cracks, resulting in overall instability. And these conditions are consistent with the prediction made by the stress wave propagation simulation study. The research results have certain guiding significance for the stability analysis and hazardous area prediction of tunnel blasting with existing cracks.

show abstract

“…1), which has an important impact on the stability of the composite structure (Ghasemi et al, 2019;Zhu and Yu, 2020;Sharafisafa et al, 2020). The occurrence of cracks in the rock mass is random, and the mechanical properties of cracks in different parts of the same rock mass are different (Shirole et al, 2020;Liu et al, 2020;Du et al, 2020;Zhou et al, 2020). A large number of studies and practices show that cracks change the mechanical properties of rock mass and change the process of energy storage and release (Luo et al, 2020;Bain et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

The effect of crack characteristics on the mechanical properties and energy characteristics of coal-rock composite structure

Li¹

2022

Acta Geodynamica Et Geomaterialia

View full text Add to dashboard Cite

With the gradual increase of coal mining intensity, many coal pillars need to be left near the stope. The stability of the composite structure of coal pillars and their overlying strata determines the safety of the whole stope and the surface. This paper conducts uniaxial compression tests on coalrock composite structures with the same lithology and the same coal-rock height ratio and finds the coal-rock composite structure's mechanical properties and failure characteristics have greater discreteness. Combining the CT images of rock and coal, it is concluded that the main reason for the discreteness of the composite structure test results is the different crack characteristics in the rock specimen and the coal specimen. Therefore, this paper uses the PFC numerical simulation software to analyzes the influence of the crack characteristics on the mechanical properties, failure characteristics, and impact energy index of the coal-rock composite structure. The sensitivity factors are used to analyze the influence of crack angle, crack length, crack number and crack position on the peak stress, total crack number, and impact energy index of the coal-rock composite structure. The research results can provide a theoretical basis and guidance for preventing the instability and failure of the coal pillar-roof composite structure.

show abstract

The characteristics of high speed crack propagation at ultra high loading rate

Cited by 11 publications

References 25 publications

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Numerical Study on the Dynamic Propagation Model of Cracks from Different Angles under the Effect of Circular Hole Explosion

The effect of crack characteristics on the mechanical properties and energy characteristics of coal-rock composite structure

Contact Info

Product

Resources

About