To calculate sound wave velocity, we performed the Hsu-Nielsen lead break experiment using the ANSYS/LS-DYNA finite element software. First, we identified the key problems in the finite element analysis, such as selecting the exciting force, dividing the grid density, and setting the calculation steps. Second, we established the finite element model of the sound wave transmission in a plate under the lead break simulation. Results revealed not only the transmission characteristics of the sound wave but also the simulation and calculation of the transmission velocity of the longitudinal and transverse waves through the time travel curve of the vibration velocity of the sound wave at various nodes. Finally, the Hsu-Nielsen lead break experiment was implemented. The results of the theoretical calculation and simulation analysis were consistent with the experimental results, thus demonstrating that the research method using the ANSYS/LS-DYNA software to simulate sound wave transmissions in acoustic emission experiments is feasible and effective.

Resonance demodulation is a commonly used rolling bearing fault diagnosis method, but resonance frequency of traditional resonance demodulation technology has a certain discreteness due to differences in terms of processing, testing and installation of sensor to collect fault information, so parameter of band-pass filter needs manual predetermination. At the same time, as information of early bearing minor fault is often submerged in strong background noise, signal to noise ratio is low. Application of traditional resonance demodulation method to improve signal to noise ratio is with limited capability, and diagnosis effect is not obvious. This paper makes use of the equivalence of electrical resonance system and mechanical resonance system and gains resonance of sensor output signal through electrical resonator, which breaks through shortcomings of traditional method, achieve ultra narrow brand high-resolution detection, and improves signal to noise ratio of fault feature signal. Finally, verification is done through simulation fault bearing signal and actually collected fault signal. The results proves validity and effectiveness of the proposed method which has an important guiding significance for engineering