Finite Element Analysis Of Rotary Ultrasonic Machining Mechanism

With the development of materials science, a large number of non-metallic brittle materials and various composite materials are used widely in machinery, electronics, automobiles,aerospace, and cutting tool industries for their excellent properties:high hardness, high thermal resistance and corrosion resistance, etc. such as engineering ceramics, optical glass, quartz, etc. However, it's quite difficult and expensive to machine non-metallic brittle materials by traditional processing methods for their high hardness, brittleness and good insulation. Rotary ultrasonic machining(RUM) has been proven to be an effective way to process hard and brittle materials by a lot of practice. RUM is characterized by a small cutting force on the workpiece, high machining accuracy, high machining efficiency and fewer side effects.RUM has been playing an increasingly important role in industry, so national experts and scholars have done a lot of theoretical analysis and experimental research about RUM mechanism. To some extent, it made RUM technology more and more mature. However, these studies about RUM mechanism mostly just made qualitative analysis and obtained approximate conclusions through a large number of experimental results and data, having no clear understanding of the microscopic removal process of materials.This paper did a comprehensive analysis on RUM mechanism in theory. Further more, the nonlinear finite element program ANSYS/LS-DYNA was used to simulate the process of RUM to describe the mechanism of RUM in further detail. The main contents include:1. In the process of researching RUM mechanism, the domestic and foreign research state of the tradition ultrasonic machining and RUM material mechanism were analyzed and generalized. Two mathematical models of material removal rate(MRR) were established according to the different material removal ways in RUM:Cutting removal model and peeling removal model. Both models can explain clearly the relations between process parameters (rotation speed, tool amplitude, static pressure, etc.) and the material removal rate in RUM.2.The nonlinear finite element program ANSYS/LS-DYNA was used to simulate the process of RUM. The study subjects of this simulation were diamond grits and the glass panel. This paper has simulated the process of single spherical, cubical, cuneal, subulate abrasive and combination of kinds of abrasive impacting and rotary impacting the glass panel respectively. Material removal ways, development of cracks, stress and structure distortion of the workpiece and the influence of processing parameters on the MRR were analysed intuitively through the simulation results. To some extent, it can verify visually the existing theoretical analysis on RUM mechanism and guide experimental study more dionally.