Study On Modeling Of Axial Ultrasonic Grinding Force Of High Strength Steel

Axial ultrasonic vibration grinding is a complex grinding method,which applies ultrasonic vibration to the axial direction of grinding wheel on the basis of common grinding technology.Ultrasound vibration-assisted grinding(UVAG)can effectively improve grinding characterization parameters such as surface quality of workpiece,grinding force,grinding temperature and tool wear.Grinding force is one of the most important grinding process parameters,which is directly or indirectly related to surface roughness of workpiece,grinding temperature,specific energy of grinding,service life of grinding wheel and so on.It is very important to study grinding mechanism.In this paper,the mechanism of ultrasonic grinding process is revealed by taking ultrasonic grinding force as the starting point.The main contents are as follows:The grinding wheel surface model with spherical abrasive as main component,positivetail distribution of abrasive height and random distribution of abrasive spacing is established.According to the theory of grinding kinematics,a real-time grinding cross-section area model of single abrasive is established by introducing the real-time change of cutting depth of single abrasive through the motion track equation of single abrasive.By considering the "voidcutting effect" existing in actual grinding process,a model of actual grinding area of grinding wheel in ultrasonic vibration grinding was established.The mechanical properties of 12Cr2Ni4 A round bar specimens were investigated by tensile tests,and the normal tensile and full-range ultrasonic vibration tensile tests were carried out respectively.The experimental results show that the stress-strain curves in the elastic stage coincide highly and the elastic modulus is the same,but the whole process of ultrasonic vibration stretching reaches the yield limit earlier and enters the plastic deformation stage.The simulation of 12Cr2Ni4 A alloy steel under uniaxial tension with intermittent vibration is carried out by using finite element software.High frequency sinusoidal displacement vibration was introduced at the lower end of the round bar specimens to analyze its effect on the tensile results of 12Cr2Ni4 A alloy steel.The results show that the stress decreases sharply and oscillates during the plastic vibration stage.The stress softening equation is used to calculate the ultrasonic vibration softening factor.According to the theory of conical horn,the structure of the horn is designed,and the modal analysis is carried out by using the finite element software ABAQUS,so as to meet the requirements of resonance frequency.By using the orthogonal cutting principle,considering the actual grinding area of ultrasonic vibration and the influence of ultrasonic vibration on the mechanical properties of materials,a prediction model of ultrasonic vibration grinding force was established.In order to analyze the influence of various factors on grinding force,a grinding force test rig was established to study and analyze the grinding force,and an orthogonal grinding experiment was designed to study and analyze the influence of various factors on grinding force.Singlefactor grinding experiments were designed by selecting grinding depth,wheel speed and feed speed,and compared with the predicted grinding force.The results show that the model can correctly predict the variation trend of grinding force,but there is a certain degree of deviation.