Analysis Of Dynamic Properties And Energy Dissipation Characteristics Of Magnetite Quartzite After Microwave Irradiation

In order to explore the mechanism of rock fragmentation caused by microwave radiation,magnetite quartzite was taken as the research object and microwave radiation and Hopkinson bar were used as the test tools,the dynamic properties,failure modes,energy dissipation law,and the relationship between fragmentation energy dissipation and particle size of magnetite quartzite after microwave irradiation were studied.1)The impact pressure and confining pressure have strong influences on the dynamic characteristics of magnetite quartzite after microwave irradiation.Under the same impact pressure and different confining pressures,the greater the microwave predamage,the shorter the "sudden change" time of the pre-peak stress curve,and the less obvious the "strain rebound" after the peak stress;Under the same confining pressure and different impact pressure,the maximum strain of magnetite quartzite decreases with the increase of impact pressure.The change of microwave radiation parameters leads to the disappearance of "strain rebound" or "stress mutation" before the peak stress.2)The failure mode of magnetite quartzite under dynamic and static combined loading changes greatly.The failure modes of magnetite quartzite without microwave irradiation are mostly compression shear or axial splitting.The fracture shapes of magnetite quartzite after microwave irradiation are related to microwave pre-damage,dynamic load,and confining pressure,and their combination forms are more diversified.3)The greater the microwave irradiation pre-damage,the greater the energy dissipation rate of magnetite quartzite;The confining pressure hinders the evolution of pre-damage of magnetite quartzite.The increase of wave impedance leads to the decrease of energy dissipation rate;The energy utilization rate of magnetite quartzite after microwave irradiation is better than that without microwave irradiation.4)Based on fractal theory,a relationship model between fragmentation and energy dissipation of magnetite quartzite pre-damaged by microwave radiation is established.Figure 28;Table 15;Reference 75...