Research On Ultrasonic Cutting Process Simulation And Experiment For Aramid Honeycomb Material

Ultrasonic assisted cutting is widely used in the field of weakly-rigid and difficult-to-machine materials such as aramid honeycomb material,as it can effectively reduce the cutting force and cutting heat,improve the processing efficiency and the surface quality of material to be processed.Although the process optimization of ultrasonic cutting can be studied by experiment,a large number of ultrasonic cutting experiment will consume huge manpower,material resources and time.Besides,the microscopic damage surface characteristics of aramid honeycomb material are difficult to represent during the experiment.On the contrary,simulation can effectively compensate for the shortcomings of the ultrasonic cutting experiment.Because the finite element simulation model can not only represent the interface characteristics of contact between tool and aramid honeycomb material but also obtain the cutting force during the ultrasonic cutting process conveniently,which is of great significance to the optimization of cutting process parameters,the development of ultrasonic equipment and the research of special tool.Therefore,the simulation and experiment research on the ultrasonic cutting process for aramid honeycomb material are carried out,aiming to determine the optimal finite element simulation model to guide the optimization of ultrasonic cutting process parameters.And the micro-fracture model of honeycomb material,the ultrasonic cutting simulation model for triangular blade,the ultrasonic cutting simulation model for circular cutter and the optimization of ultrasonic process parameter based on simulation analysis have been studied.The main research work and research results are as follows:(1)The constitutive properties and mechanical properties of honeycomb material were studied.Based on the constitutive characteristics of aramid honeycomb material,the constitutive equation of single-layer isotropic aramid honeycomb material was derived.According to the bending theory of small-deflection thin plate combined with the different machining processes of triangular blade and circular cutter,the deformation formula of honeycomb material under the triangular blade and circular cutter during the ultrasonic cutting was derived.In addition,the fracture characteristic and the judgment method of fracture state for honeycomb material during the ultrasonic cutting were pointed out.(2)The vital technology of ultrasonic cutting simulation modeling for aramid honeycomb material was studied.According to the processing characteristics of ultrasonic cutting and the structural characteristics of aramid honeycomb material,the high-strain-rate characteristic of ultrasonic cutting is realized by reducing the material fracture strain parameter of simulation model.The single-layer simulation model and multi-layer simulation model of aramid honeycomb material were established respectively by regarding the aramid paper and phenolic resin in the cell-wall structure of aramid honeycomb material as a whole part or assembly.Furthermore,three single-layer simulation models were established from the perspective of geometric modeling.The constitutive property of material were defined aiming at the above three single-layer simulation models and multi-layer simulation model,respectively.Finally,the fracture characteristic of ultrasonic cutting aramid honeycomb material in simulation was analyzed.(3)The ultrasonic cutting simulation under triangular blade was studied.The displacement of cell-wall node in the feed direction for simulation post-processing model and the deflection of corresponding position in the cell-wall material based on the thin plate theory were compared.In addition,the consistency of ultrasonic cutting simulation result and actual cutting experiment result was comparatively studied by the cutting force in the feed direction and the deformation damage process of honeycomb material.The research shows that the comprehensive precision of multi-layer simulation model is highest,but it consumes a long time during simulation.On the other hand,the comprehensive performance of layer modeling method in the single-layer simulation is best,which can also predict the surface damage characteristics of aramid honeycomb material.(4)The ultrasonic cutting simulation under circular cutter was studied.The layer modeling method of single-layer simulation model for aramid honeycomb material was adopted in the ultrasonic cutting simulation under circular cutter.Then the cutting force between simulation and experiment as well as the displacement between simulation and theoretical model were compared,which verify the validity of ultrasonic cutting simulation model under circular cutter.(5)The optimization of process parameter was studied.By introducing the finite element simulation technology and taking the minimum ultrasonic cutting force as the optimization target,the optimal ultrasonic cutting process parameters under triangular blade and circular cutter were obtained respectively,which combined with the orthogonal experiment scheme and the range analysis method.The results of simulation optimization show that the optimized ultrasonic cutting process parameter can reduce the ultrasonic cutting force effectively.The optimal process parameter obtained by the simulation method can greatly reduce the research period of ultrasonic cutting process parameter optimization.