| In order to achieve efficient and safe roadway excavation,the vibration technology-assisted rock breaking is combined with cutter cutting to propose a cutter vibration cutting method for the problems of difficult wedging into hard rock,inefficient rock breaking and serious wear of the mechanical tools in the disc cutter of the cantilever roadheader.By using a combination of theoretical analysis,indoor tests and numerical simulations,this thesis conducts an in-depth study of the vibration cutting performance of disc cutter.Based on rock crushing characteristics,damage criteria,and theories related to rock breaking by rolling cutter,the cutter breaking mechanism is studied and the cutter breaking process is analysed.Based on the fracture mechanics theory and integral theory,a mechanical model of the cutter breaking process is developed to obtain the peak cutter breaking propulsion force and the corresponding depth.Based on the numerical simulation model of rock breaking by cutter vibration based on finite element software,the dynamic simulation of rock breaking process by cutter vibration was carried out.With the help of numerical simulation,the rock cutting process with and without excitation of the cutter is compared and analysed,and the rock damage evolution process under the cutter cutting and breaking is revealed.The influencing factor of cutter posture,cutter diameter,cutting thickness and other factors on the cutter vibration cutting performance is studied,which provides important reference for the subsequent cutter vibration cutting test research.Based on the test purpose and numerical simulation test results,a cutter vibration rock-breaking test bench was built to study the difference of rock-breaking process of cutter cutting with and without excitation,and the influencing factors of rock-breaking performance of cutter were studied by orthogonal test.The rock breaking volume,the specific energy of rock breaking and the cutting speed were used as the evaluation indexes for rock breaking performance.The effects of the amplitude of the excitation force,the excitation frequency and the traction force on the rock breaking performance of cutting were determined by extreme difference and variance analysis..Based on the orthogonal test results,the influence factor of excitation force amplitude,excitation frequency,traction force,and cutting thickness on the rock breaking performance of cutter vibration cutting is obtained through single-factor test,and a better parameter range is given.Based on the theory of tribology and heat transfer,a thermo-mechanical coupling finite element model is established for cutter vibration cutting,and the temperature rise process and thermal stress of cutter cutting and rock breaking are simulated and analysed,and the reliability of the numerical model is verified using tests.The temperature change of the cutter breaking process is studied,the effect of cutting speed,vibration frequency and other factors on the temperature of the cutter is obtained,the distribution of thermal stress of the cutter and its change law are obtained,and the influence law of rock strength on the maximum temperature and maximum stress of the cutter is analysed.There are 85 figures,16 tables and 113 references in this thesis. |
