3D Modeling For Asphalt Concrete Paving And Numerical Simulation For Cutting Of Miller Based On Discrete Element Method

With the focus of construction for national highway is turning to reconstruction and maintenance of pavements, the demand for road miller is increasing continually as an important machine for maintenance of asphalt concrete paving. The research of domestic self-developed road miller with high-performance brooks no delay. The force of miller can be quantitative expressed by numerical simulation during working and numerical simulation has become an important mean of research for road miller’s performance. The key problem of simulation is to model the asphalt concrete paving with complex mechanical properties. In this paper, three-dimensional discrete element method is used to model asphalt concrete paving that fits the macroscopic mechanical properties of road. Cutting process of road miller is simulated and cutting force is quantitatively expressed during simulation. The measurement criteria of energy consumption and efficiency during its cutting process are inferred. Influence between variation of working parameters, energy consumption and efficiency are quantitative analyzed. The critical condition of utilizing vibration cutting in road miller is inferred, the mode and parameters of vibration are optimized during simulation. The main research works in this paper are as follows:(1) The kinematics and mechanics model of milling drum in road miller during cutting process are inferred and the working parameters required by quantitative analysis are extracted. The overall cutting force of milling drum during utilizing vibration cutting in road miller is inferred, attaching vibration cutting can effectively reduce cutting force in road miller is verified qualitatively by using method of mechanics. The advantages and disadvantages of finite element method and discrete element method is compared, the discrete element method is chosen to study the cutting properties of asphalt concrete paving.(2) Uniaxial compression and splitting tensile test are used to measure the compression modulus and tensile modulus of asphalt concrete paving, the obtained macroscopic criteria are used for verifying microcosmic parameters of contact and connection. Algorithm is programmed in PFC3 D to generate coarse aggregate with irregular polyhedron shape. The discrete element specimens of asphalt concrete paving are generated with particles of coarse aggregate and particles of asphalt mastic according to grading characteristics. Microscopic parameters of contact and connection are set and verified according to the obtained macroscopic criteria. The discrete element model of paving is obtained which mechanical properties meet the asphalt concrete paving.(3) Software Proe is used to model miller, the three-dimensional cutting model of miller is established combining with the extracted working parameters and DEM model of asphalt concrete paving in software PFC3 D. The inferred specific energy consumption g is used for criterion of energy consumption. The inferred removal rate of asphalt concrete paving Q is used for criterion of efficiency. The cutting force of miller along direction of X by quantitative simulationxF is used for criterion of wear resistance. The influence between variation of working parameters and working process of road miller are calculated and discussed.(4) Kinematic model is established to infer the critical condition of utilizing vibration cutting in road miller. The vibration is utilized in the established three-dimensional discrete element model of road miller. The cutting force of miller along direction of X obtained by quantitative simulationxF is used for the estimated criterion of virtual experiments to research the improvement of cutting force when utilizing different mode of vibration during working process. The optimized mode of vibration is obtained, the amplitude and frequency of vibration are optimized.