The influence of microwave treatment on the mode I fracture toughness of granite

Ge, Zhenlong; Sun, Qiang; Xue, Lei; Yang, Tian

doi:10.1016/j.engfracmech.2021.107768

Cited by 45 publications

(4 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, in this study the thermal expansion coefficient of quartz varies non-linearly with increasing temperatures, whereas for the other two minerals the variation is linear. Finally, the higher values of dielectric properties of biotite lead to a higher heating in this mineral (see Figure 6), which may cause higher thermal stresses and consequently tensile cracks in the surrounding grains [61].…”

Section: Microwave Pretreatment On Numerical Rock Samplementioning

confidence: 99%

Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite

2023

View full text Add to dashboard Cite

Thermal pretreatments of rock, such as conventional heating and microwave irradiation, have received considerable attention recently as a viable method of improving the energy efficiency of mining processes that involve rock fracturing. This study presents a numerical analysis of the effects of thermal shock and microwave heating on the mechanical properties of hard, granite-like rock. More specifically, the aim is to numerically assess the reduction of uniaxial compressive strength of thermally pretreated specimens compared to intact ones. We also compare the performance of these two pretreatments (conventional heating and microwave irradiation) in terms of consumed energy and induced damage. Rock fracture is modelled by a damage-viscoplasticity model, with separate damage variables in tension and compression. A global solution strategy is developed for solving the thermo-mechanical problem (conventional heating) and the electromagnetic–thermo-mechanical problem (microwave heating). The electromagnetic part of the microwave heating problem is solved in COMSOL Multiphysics software Version 6.1 first. The electromagnetic solution is used as an input for the thermo-mechanical problem, which is finally solved by means of a staggered explicit solution method. Due to the predominance of the external thermal sources, the thermal and the mechanical parts of the problem in both cases are considered as uncoupled. Three-dimensional finite element simulations are utilized to study the damage-viscoplasticity model. An ore-shaped three-mineral numerical rock specimen is used in uniaxial compression tests.

show abstract

Section: Microwave Pretreatment On Numerical Rock Samplementioning

confidence: 99%

Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite

2023

View full text Add to dashboard Cite

show abstract

“…There are also some scholars from the microwave action mode considerations, to explore the change rule of rock physical and mechanical properties. Through different microwave power and radiation time on the heating damage to a variety of rock specimens, Bisai et al [39] , Deyab et al [40] , Nekoovaght et al [41] , Kahraman et al [42] , and Zheng et al [43] compared and analyzed the trend of compressive strength and tensile strength of rocks before and after the microwave and showed that with the increase of microwave power and radiation time, the weakening effect of compressive strength and tensile strength gradually increases, and under the same energy, the microwave with "high power and short time" has a better damage effect on the rock; Li et al [44] , Lu et al [45] , Ge et al [46] , Yang et al [47] , and Bai et al [48] comparatively analyzed the fracture toughness and resistance index (CAI) of rocks before and after microwave and showed that the fracture toughness and resistance index (CAI) of rocks decreased exponentially with the increase of microwave power and radiation time. The change of waveguide position leads to the change of electromagnetic field distribution, which affects the rock warming and damage effects.…”

Section: Introductionmentioning

confidence: 99%

Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship

Wen,

Du,

Kong

et al. 2024

Eksploatacja i Niezawodność – Maintenance and Reliability

View full text Add to dashboard Cite

In this study, based on a microwave test, the discrete element program (PFC) is used to establish a microwave-assisted disc cutter rock-breaking model and explore the influence law of the positional relationship between microwave radiation and disc cutter penetration on rock-breaking efficiency, and the results show that: The improvement of the positional relationship has a significant effect on improving the rock-breaking efficiency, and the double-edged cutter reaches and minimum rock-breaking specific energy when breaking the rock in the center position with a waveguide spacing of 90 mm and in the inner and outer positions with a waveguide spacing of 150 mm; When the waveguide spacing is 150mm, the double-edged cutter with cutter spacing of 110mm, 130mm, and 190mm have their advantages in rock-breaking efficiency and economic benefits, which should be selected according to the actual needs of the project. The follow-up research should also fully consider the rock type, microwave parameters, cutter profile, engineering environment, and other factors for in-depth investigation.

show abstract

“…Chemical and metallurgical industries significantly contribute to global warming, since they produce a large amount of carbon dioxide (CO 2 ) annually. − One of the main sources of produced CO 2 is the combustion of fossil fuels to supply their required energy/feedstocks. This problem can partly be tackled by applying process electrification integrated with renewable electricity.…”

Section: Introductionmentioning

confidence: 99%

Temperature Distribution Assessment in Gas–Solid Reactive and Nonreactive Systems Heated by Microwaves

Adavi

Shabanian

Chaouki

2023

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Research studies have shown that selective heating of different phases in gas−solid systems exposed to microwave (MW) irradiation leads to a temperature gradient between gas and MW absorber solids. This can suppress undesired secondary gas-phase reactions and yield apparent kinetic improvements and energy savings. However, the effects of reaction exothermicity/ endothermicity, gas velocity, temperature probe location at the microscale, and MW penetration depth in fixed beds on the temperature difference between solid and gas phases exposed to MWs and temperature distribution in the fixed beds are poorly understood. Highlighting these effects was targeted in this study and accomplished with the help of multiphysics simulations by COMSOL Multiphysics (5.6). The corresponding COMSOL model was initially verified and validated by data collected from literature studies and those obtained experimentally by the authors in this study. Simulation results from the verified and validated model indicated that the temperature gradient between the gas and the MW absorber solid increases by increasing the gas velocity or switching from an endothermic reaction to no reaction and/or an exothermic reaction. In addition, the collected results show nonuniform temperature distribution in a fixed-bed reactor made of MW absorber particles irradiated by MWs due to the limited penetration depth of MWs and hotspot formation. This operational deficiency makes the large-scale design of this type of reactor very challenging for MW heating-assisted reactions.

show abstract

The influence of microwave treatment on the mode I fracture toughness of granite

Cited by 45 publications

References 35 publications

Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite

Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite

Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship

Temperature Distribution Assessment in Gas–Solid Reactive and Nonreactive Systems Heated by Microwaves

Contact Info

Product

Resources

About