Design And Numerical Simulation Of An Ultrasonic Surface Finishing And Strengthening Device

The development of various new equipment puts forward higher performance requirements for parts,with the rapid development of the manufacturing industry.The improvement of fatigue life and wear resistance plays a crucial role in improving the performance of key parts.The surface finishing technology for its effective improvement of the wear resistance,corrosion resistance and fatigue resistance is widely used in the processing and manufacturing of key parts in the fields of automobile,aircraft,construction machinery,etc.Ultrasonic surface finishing technology as a combination of ultrasonic vibration and surface finishing technology can greatly improve processing efficiency and quality,and has become a new development direction of surface finishing technology.Ultrasonic transducer as a key component of this technology,the slight change of its performance will greatly affect the processing quality,Moreover,there are many processing parameters,and it is costly to optimize the parameters through experiments.Therefore,the optimization design of the ultrasonic transducer and the simulation of the ultrasonic surface finishing process are critical for improving the stability and quality of the process.This paper describes the principle of ultrasonic surface finishing with an example of ultrasonic rolling.The structure of the ultrasonic surface finishing system is introduced.The experimental platform chooses a sandwich piezoelectric transducer as the actuator of the platform according to the functional requirements of the actuator of the platform.Firstly,the analytical method is used to obtain the preliminary size parameters of the transducer,which determines the parameter range for the optimal design of the ultrasonic transducer.The experimental platform is developed based on the fixing method of the transducer and the application requirements of the pre load.The finite element method is used to optimize the design of the transducer.The initial finite element model is established based on the dimensional parameters derived from the analytical model.Longitudinal vibration modal frequencies and electromechanical coupling coefficients to the sensit ivity of dimensional parameters have been developed using the modal analysis method.The transducer design frequency of 20 k Hz was selected.The size of the transducer is adjusted according to the conclusion of sensitivity analysis to determine the final size of the transducer.The maximum stable output amplitude of the transducer is obtained by harmonic response analysis,which can reach 21.77 ?m at a voltage of 500 Vp-p.The effect of tool heads of different sizes and materials on the resonance frequency and amplitude of the transducer is analyzed to provide a reference for tool head replacement.A prototype of an ultrasonic transducer is manufactured,and the inductance required for the impedance matching of the transducer is 8.5 m H,which is calculated by transducer impedance analysis.The actual resonant frequency of the transducer is measured as 19.633 k Hz by laser vibration meter.The output amplitude range of the transducer is measured by a laser displacement sensor to be 22.625 ?m when the voltage is 500 Vp-p.The mechanism of ultrasonic surface finishing is further analyzed to determine a suitable material constitutive model.Numerical simulation of ultrasonic surface finishing processing is carried out using ABAQUS.The effects of key parameters such as static pressure,number of machining cycles and amplitude on the surface roughness and residual stress are studied.The results show that the static pressure has a greater effect on the reduction of surface roughness than the number of processing cycl es and amplitude.Surface roughness can be reduced from 6.3 ?m to 0.81 ?m under static pressure of 800 N.Moreover,the maximum residual compressive stress,depth and the range of the residual compressive stress can be significantly increased with the incr ease of static pressure.The value and depth of the maximum residual compressive stress are 64.97 MPa and 0.03 mm when the static pressure is 800 N,it is 1.08 times and 2 times higher than that of 100 N.Also,the improvement of residual stress is not significant for the number of processing cycles and amplitude.The principle of ultrasonic surface finishing processing and the composition of the processing system is researched in this study.A sandwich piezoelectric longitudinal vibration transducer with a detachable tool head is designed through the analytical model and finite element analysis.An experimental platform is designed and manufactured for processing plane specimens.Finally,the influence of processing parameters on the surface characteristic parameters of the specimen is studied by the finite element software ABAQUS.