Optimization design of ultrasonic knife cutting system based on finite element model

The ultrasonic cutting machine has wide application in material processing in cutting various hard-and-brittle materials, such as composite material. An ultrasonic cutting system is proposed, and a finite element model of the proposed system is established by ANSYS software. Then modal analysis and harmonic response analysis of the proposed system are conducted by ANSYS software. It shows that the proposed system has an axial vibration modal around the frequency of 40 kHz. At the same time, the vibration nodes of the proposed system locate at the erection loop and the center of piezoceramics. These locations accord with the design demands. Based on the finite element model, the proposed system is fabricated, and the natural frequency of the transducer is measured by an impedance analyzer and a laser doppler analyzer. The measured natural frequency is 40.26 kHz, and the obtained frequency and impedance curve is smooth. The relative error between the measured and the predicted result is only 0.83%, and the maximum amplitude of vibration is 14.52 μm. This indicates that the predicted results well agree with the measured results.