Research On Modeling Of Ultrasonic Machining Stability Of Microwave Absorbing Honeycomb Materials

The aramid honeycomb material is a black high in-plane stiffness composite material formed by impregnating the aramid honeycomb with a resin with absorbing properties.It has all the properties and advantages of the aramid honeycomb material and is widely used in the military and aviation field.This paper takes the absorbing honeycomb material and its cell wall as the research object,starting from the material cutting method and cutting tool selection and the mechanical properties based on experiments,the modeling research on the ultrasonic cutting stability of the absorbing honeycomb material is carried out.The research work and results of the thesis are as follows:(1)Analyze the absorbing honeycomb material and its processing method,and propose the ultrasonic cutting process of the absorbing honeycomb material.In view of the high hardness and brittleness of the absorbing honeycomb material,the commonly used processing methods and different characteristics of honeycomb materials are compared and analyzed,and it is proposed that ultrasonic cutting is expected to become the mainstream cutting method of absorbing honeycomb materials;refer to the tools and tools used in ultrasonic cutting of aramid honeycomb materials.Technological characteristics,the use of "straight-edged knife + disc knife" combination to form "rectangular" chip as the technological characteristics of the ultrasonic cutting process of absorbing honeycomb material.(2)The mechanical performance parameters of the wave-absorbing honeycomb material are obtained by experiment,and the dynamic parameters of the cell wall panel are obtained by combining theory with simulation.The performance acquisition experiment of the absorbing honeycomb material was carried out,combining the experimental curve and theoretical formula,the strength,elastic modulus,density and other mechanical performance parameters of the absorbing honeycomb material and its cell wall panels were obtained.The obtained mechanical performance parameters are used to simulate the vibration of the cell wall plate,and combined with the theoretical formula,the dynamic parameters of the cell wall plate during the vibration process are obtained.(3)Analyze the motion characteristics of the disc cutter and the straight edge cutter during ultrasonic cutting,and establish the kinematics equations of the two kinds of cutting tools respectively.Considering that for the disc cutter,the cutting effect is the X and Z rotation movement.For the straight-edge cutter,in the machining process of forming rectangular chips,the tool only has the Ydirection and Z-direction movement,so two are established respectively.The kinematic equations of this kind of tool in different directions during ultrasonic cutting provide theoretical guidance for the establishment of the stability model later.(4)Research on the stability of the cell wall plate in ultrasonic cutting with a disc cutter.The ultrasonic cutting of the honeycomb material with a disc cutter was carried out,the ultrasonic cutting force coefficient was calibrated,and the natural frequency,vibration mode and the time domain response under ultrasonic excitation of the disc cutter were obtained by simulation to draw and reflect the ultrasonic cutting absorption of the disc cutter.The stability Lobe diagram of the stability process of the wave honeycomb material.Select the combination of cutting parameters in the stable area and the non-stable area on the Lobe diagram to conduct cutting experiments respectively,compare the surface quality and tool wear of the wave-absorbing honeycomb material,and verify the feasibility of the stability model.(5)Research the fracture mechanism of the cell wall panel by ultrasonic cutting with a straightedged knife,and propose that the toughening effect of ultrasonic vibration on the panel is the main cause of fracture.Analyzed the force process of the cell wall panel in a single cycle during the cutting with a straight-edge cutter.The deflection equation and stress equation of the honeycomb cell wall were established using the theory of small deflection of the elastic thin plate;combined with the analytical model and finite element simulation,the deformation of the honeycomb cell wall was analyzed.Characteristics and fracture characteristics.(6)Study on the stability of the cell wall panel in ultrasonic cutting with a straight-edged knife.The straight-edged tool ultrasonic cutting system is simplified to a two-degree-of-freedom system;the stability model of the tool feed direction is established considering the influence of the cutting force on the stability of the cell wall plate,and the stability judgment conditions are obtained;comprehensive simulation,The theoretical and experimental data draws a graph of the depth of cutacoustics/cutting parameters,which provides better cutting and acoustic parameters for the ultrasonic stable cutting of straight-edge cutters.