Design And Analysis Of Giant Magnetostrictive Ultrasonic Transducer Of Incremental Sheet Metal Forming

Adding ultrasonic to Incremental sheet forming(ISF)have great advantages,such as reducing the yield stress and forming force,increasing forming limit,improving surface quality of the components,reducing springback of the parts.Transducer is the core of the ultrasound system based on the US-ISF(Ultrasonic Incremental Forming),and which has a direct relationship with the power,frequency,amplitude,lifetime of the ultrasound system.Research and development of high-performance ultrasonic transducers is one of the most important tasks in the field of US-ISF technology and the entire ultrasonic processing field.GMM(giant magnetostrictive material)is a new type of functional material,with a high power capacity and fast response speed,opens opportunities for high power and large amplitudes in an ultrasonic machining system.In this paper,a novel approach about GMM ultrasonic transducer based on ISF was introduced and discussed.The frequency equations of the ultrasonic vibrator were derived with the transmission matrix and four-terminal network method.The structure of the transducer were designed according to the frequency equations.The bias magnetic field and the coil components are designed according to the magnetostrictive strain curve of the GMM material.The finite element model of the transducer was established in ANSYS finite element software,and modal,frequency response and magnetic field strength was analyzed by the method of piezoelectricity-to-piezomagnetic method.The results show that the error between resonant frequency and the design requirement of the designed transducer were less than 5%,and the vibration mode of the transducer was consistent with the theoretical design.Similarly,the magnetic field analysis of the transducer was carried out in ANSYS finite element software,and the results show that a good magnetic circuit was formed,and no magnetic flux leakage phenomenon occurred.The correctness of the bias magnetic field and the alternating magnetic field was verified through the simulation.At the same time,the influence of different magnetic permeability on magnetic field strength and magnetic field uniformity was researched.Through the analysis of the harmonic magnetic field of the transducer,it was found that there is a great eddy current on the GMM rod under the excitation of high frequency,resulting in a serious skin phenomenon.So some special treatments must be done to the GMM rod.The experimental prototype of the transducer was fabricated,and the impedance of the transducer was analyzed.A corresponding matching capacitor was designed according to the impedance analysis.Through the impedance analyzer tests,the transducer resonant frequency of 19.225 k Hz and a small mechanical quality factor was acquired.The amplitude measurement platform of the transducer was built and the influence of different electrical signal input on the amplitude of the transducer was studied.The results show that the maximum output amplitude of the transducer is 15μm,which is more suitable for ISF.