Multi-variable Optimization Design Of Composite Horns And Open-hole Cylindrical Rods

As a green,non-polluting technology,power ultrasound solves many key problems in industry,agriculture and medical care through the effects of mechanical,cavitation and thermal effects generated by ultrasonic waves in the medium,improving and improving processing or processing.Speed and efficiency.Ultrasonic vibration system is an important part of it,mainly including ultrasonic generator,transducer and horn.In actual work,the tool head is also installed at the front end.The function of the transducer is to convert electrical power into mechanical vibration,and the amplitude of the vibration of the radiating end face is generally only a few microns.In ultrasonic processing and processing,the vibration amplitude of the output end face generally needs tens to hundreds of micrometers,and the transducer must be terminated by a horn to amplify the amplitude.Therefore,the design performance of the horn is better,which not only improves the processing efficiency,but also prolongs the service life of the transducer.The amplification factor is an important performance parameter of the horn.Different shapes and materials have a great influence on the amplification factor of the horn.Sometimes a horn with a good amplification factor and stability is required.Usually,the output end has a small area and the input end has a large area,so that the ultrasonic energy is concentrated on the smaller output end face to achieve the energy collecting effect.In the large amplitude power ultrasonic application,under the condition that the input electric power of the transducer is constant,the area of the output end of the horn needs to be large,and the energy can be concentrated,which can be applied to the ultrasonic processing or the ultrasonic processing in a wider range.Object.In response to the above problems,the finite element software is used to simulate the horn model,and the optimization method is used to obtain a larger amplification factor.The specific work is as follows:(1)Deriving the performance formula of the three-stage composite horn according to the wave equation.The exponential deformation rod is the most stable to the load,and the two types of varactors,exponential-cylinder and exponential-cone,are calculated.The frequency equation and the magnification are programmed to optimize the length of the two rods of the horn under the condition of a certain resonant frequency to obtain the maximum magnification.(2)Multivariate optimization design of exponential-cylinder and exponential-cone horns to determine the geometry and resonant frequency of the horn.Modeling,modal calculation and parameters of the two horns using ANSYS software Optimized design.The results obtained by the traditional analytical method and the finite element method are basically the same.Compared with the pre-optimization,it can be seen that the finite element optimization design method can effectively optimize the horn length and obtain the maximum magnification.(3)For large amplitude power ultrasound applications,increasing the amplification factor,the first method is to cascade the multi-stage horn,and the second method is to increase the input electrical power of the transducer.The former will increase the cost,and the rear will shorten the life of the transducer.In view of the above problems,a cylindrical rod with a transverse rectangular through hole at the front end is proposed.The finite element software is used to calculate the amplitude amplification ratio of the cylindrical rod and the displacement distribution of the output end face.The influence of the size of the hole on the resonant frequency of the cylindrical rod is analyzed.The optimal design of the opening size is obtained at the given frequency.The magnification shows that the output of the horn has both longitudinal vibration and bending vibration.After the combination of the two,the magnification is greatly improved compared with the traditional horn.The resonance frequency is greatly affected by the distance t from the end face.The influence on the opening length a and the opening width b is small.The relative stress values around the holes are calculated.The stress distribution curves before and after optimization are smooth and there is no stress mutation.(4)The solid cylindrical rod and the perforated cylindrical rod before and after optimization are processed,and their resonance frequency,displacement distribution of the output end face and vibration mode,and amplitude amplification with respect to the input end of the rod are tested by a laser vibrometer.The experimental test results are in good agreement with the theoretical calculations.The test results also show that the excitation voltage is linear with the amplitude of the output end face of the open-cell cylindrical rod after the cylindrical rod is connected to the transducer.