Structural Design And Frequency Calibration Of The Cutting Insert Of The Ultrasonic Scalpel

As an important part of the ultrasonic scalpel system,the cutting insert has vital influence on the performance of the ultrasonic scalpel.However,the theoretical analysis,structural design,simulation,frequency calibration,and other issues of ultrasonic scalpels are still required systematic research and analysis.Therefore,this article takes the cutting insert of the ultrasonic scalpel as the research object,and uses a theoretical calculation,finite element analysis,experimental verification and other methods to carry out the structural design and frequency calibration research of the cutting insert of the ultrasonic scalpel.The main research work of the paper is as follows:(1)Taking thin rod of equal section as research objects,the longitudinal vibration laws of the thin bar under different boundary conditions,such as free at both ends,one end is free and the other end is excited by simple harmonic force,free at one end and fixed at the other and one end is free and the other end is excited by a simple harmonic displacement,is analyzed,and the design of the cutting insert of the ultrasonic scalpel is theoretically analyzed based on the phenomenon of "local resonance".The calculation formula of the excitation force was deduced,and the damping value was determined to be0.055 according to the simulation and experimental data.A finite element simulation model of the cutting insert of the ultrasonic scalpel was established.(2)Based on the analysis of design requirements and the optimization of material selection,the structure of the cutting insert of the ultrasonic scalpel was designed by taking into account the amplitude gain,improvement of stress concentration,the shape of the cutter head,and the vibration mode by using the established theoretical model and simulation model.The feasibility of the cutting insert of the ultrasonic scalpel design based on the theoretical model and simulation model was verified by measuring the longitudinal vibration frequency of the cutting insert and the vibration displacement of the blade head.(3)Aiming at the problem that the longitudinal vibration frequency of the cutting insert of the ultrasonic scalpel deviates from the design value due to material differences and other reasons,a method for calibrating the longitudinal vibration frequency of the cutting insert of the ultrasonic scalpel is proposed,i.e.,a stepped shaft segment of a certain length is designed at the antinode position of the radial vibration displacement of the cutting insert of the ultrasonic scalpel.At the same time,the finite element simulation is used to analyze the influence of the structural parameters of the shaft section on the longitudinal vibration frequency.Based on this,a calculation model for the calibration of the longitudinal vibration frequency is established and verified by experiments.