Design and performance investigation of an underwater ultrasonic percussive drill for seabed mineral exploration

To address the limitations of traditional drilling equipment, such as large size, high power consumption, and difficulties with waterproofing, an underwater ultrasonic percussive drill (UUPD) based on piezoelectric drive is proposed. The structure and size parameters of the piezoelectric actuator are designed and its performance is experimentally verified. The maximum output amplitude of the piezoelectric actuator is 78.6 μm in air and 52.3 μm in water. Additionally, the dynamic characteristics of the UUPD are calculated theoretically and analyzed by simulation, and the influence of system parameters on vibration characteristics is revealed. A prototype of the UUPD is developed, and a performance testing platform is established, and drilling comparison experiments and power consumption test are carried out to evaluate the performance of the UUPD. Experimental results demonstrate that the UUPD is capable of breaking rocks with varying hardness (5–50 MPa) under small drilling pressure (around 6 N) and low power consumption (approximately 57 W). The UUPD proposed in this paper offers advantages, including low drilling pressure, low power consumption, light weight and compact structure, showing a good application prospect and providing an effective technical means for deep-sea hard mineral rock drilling and sampling.