Investigation on the Evolution of Shock Wave Energy in the Fracturing Process via High voltage Electric Pulse.

High voltage electric pulse (HVEP) was used to perform concrete cracking experiments to demonstrate the feasibility of this technique for cracking hard objects. The results of the study show that HVEP fracturing technology has great potential for application. This article uses a high-speed camera to record the crack expansion process, and analyze the relationship between crack expansion speed and time. The Hilbert–Huang Transform (HHT) is used to analyze the vibration signal generated by the shock waves (SWs). The energy evolution law of SWs is elaborated by the time–frequency characteristics of the vibration. The distribution of the vibration energy is more concentrated between 0 and 100 Hz. The increase of capacitance value will produce stronger vibration peak energy and force. The presence of cracks will cause the vibration energy propagation to be blocked and the energy decay rate to be accelerated. Also, the energy will be shifted in the frequency domain due to the presence of cracks. Highlights: A high-power high voltage electric pulse fracturing equipment is designed and manufactured. The process of crack formation and expansion is recorded. Hilbert–Huang transform analysis of the time–frequency characteristics of vibration signals. Increase of capacitance enhances instantaneous energy and maximum force of discharge. Cracks cause the energy decay of shock waves to become faster. [ABSTRACT FROM AUTHOR]