Design And Mechanism Analysis Of Terminal Bendable Ultrasonic Based On Rope Driving

New medical instruments continue to emerge in the modern medical field.Ultrasonic scalpel,as a relatively advanced cutting and hemostatic equipment,has been widely used in the medical field.Ultrasonic scalpel is also known as "bloodless scalpel",which has the function of cutting and hemostasis.The working mechanism is that the ultrasonic generator generates high-frequency alternating current,converts the electrical signal into mechanical vibration through the ultrasonic oscillator,and the external ultrasonic tool bar(ultrasonic knife head)produces micro-acoustic flow effect,cavitation effect and thermal effect after contacting with biological tissues to cut and close the biological tissues.The main advantage of ultrasonic scalpel is that the inherent thermal characteristics of the knife head can simultaneously cut and close biological tissue at a lower energy,effectively reducing intraoperative pain and shortening recovery time.And keep the operating area dry and clean to provide a good operating field of vision.However,there are some problems in the use of the current ultrasonic scalpel,mainly in the less freedom of intraoperative operation,the inability to bend,and the difficulty in covering the deep intra-abdominal area for cutting and closing operations.This project is an in-depth study of the working mechanism of ultrasonic scalpel,the development of an end-bendable ultrasonic scalpel system,and the related validation tests,mainly as follows:1.By exploring the elastic wave propagation characteristics in rods,the elastic wave fluctuation models in straight rods and variable-section rods are constructed.On this basis,combined with the theory of bending beam with variable section,the elastic wave equation in bending beam with variable section is derived.2.Based on the working characteristics of ultrasonic scalpel,a new viscoelastic material,nickel-titanium alloy,was selected as the material for making ultrasonic scalpel tool rods.By investigating the material properties and the acoustic wave conduction equations,two different structural forms of ultrasonic scalpel tool bars are designed.Also,a rope-driven external load mechanism is designed to provide bending freedom at the end of the ultrasonic scalpel.3.Simulation software is used to analyze the bending stress,mode and harmonic response of the curved beam structure,obtain the stress nephogram,resonant frequency and terminal output amplitude,and optimize the curved beam structure.4.The performance test of ultrasonic scalpel was carried out to test the admittance and end amplitude under different bending angles,and the physical characteristics of ultrasonic scalpel tool bar were discussed.A biological tissue cutting test system was established,the cutting effect and temperature distribution of biological tissue were analyzed,and the working performance of bendable ultrasonic scalpel tool rod was evaluated.