Shanghai scientists develop breakthrough tech to make submarines nearly invisible to sonar

A Shanghai-based research team has developed an advanced vibration-damping technology that could significantly boost the stealth capabilities of submarines during covert operations.

Led by Zhang Zhiyi from Shanghai Jiao Tong University’s State Key Laboratory of Mechanical Systems and Vibration, the team claims their innovation could theoretically cut the detection range of enemy sonar by more than half, Caliber.Az reports via foreign media. 

The technology replaces traditional rigid engine mounts with a hybrid active-passive vibration isolation system that reduces engine noise transmitted through submarine hulls by up to 26 decibels (dB).

The system combines a steel-rubber-steel “sandwich” ring to absorb vibrations with an active layer of 12 piezoelectric actuators arranged radially around the engine. These electrically powered actuators counteract the engine’s micron-level movements by applying precise control forces via lever mechanisms.

“Research indicates that a mere 10dB reduction in underwater vehicle noise can decrease its detectable range by 32 per cent,” the study notes.

It also explains that “during low-speed navigation, mechanical noise generated by power equipment operation constitutes the primary noise source for underwater vehicles, serving as their key acoustic signature for detection—typically manifested as a series of low-frequency tonal components.” The researchers emphasize that “implementing vibration damping measures to diminish energy transmission from engines through supporting structures is crucial for enhancing underwater vehicles’ acoustic stealth performance.”

Lab tests on a scaled-down prototype yielded noise reductions of 24dB at 100Hz and 26dB at 400Hz, covering an effective frequency range of 10 to 500Hz and enabling real-time noise cancellation through a smart FX-LMS adaptive algorithm that coordinates all 12 actuators to avoid destabilizing feedback.

Despite these promising results, challenges remain, including variability in rubber stiffness under different temperatures and pressures, as well as uncertainties about the long-term durability of the piezoelectric components. The study did not specify the overall noise reduction improvement this system would achieve on actual submarines.

By Naila Huseynova