In response to the performance bottleneck of traditional underwater acoustic absorbing materials in low-frequency wideband absorption, this paper proposes a rubber-coated wavy-neck Helmholtz resonator (RWHR) and constructs a dual-objective constrained deep neural network framework (DO-DNN) to achieve the reverse design of its geometric and material parameters. To overcome the non-unique solution problem of "one performance for multiple structures" in reverse design, a dual-objective loss function is designed. The results showed that the maximum error between the peak absorption frequency and the target value is only 5 Hz, and the error of the absorption coefficient is less than 0.007. Finally, through the verification of the four-unit composite structure and the underwater pipe experiment, the designed composite structure has an average absorption coefficient of 0.67 within the 1500Hz frequency range and maintains good mechanical properties under a static water pressure of 10MPa. This has achieved the efficient and precise reverse design of low-frequency broadband sound-absorbing metamaterials, providing a new path for the research and development of deep-sea acoustic stealth equipment.

Baozhu Cheng obtained his bachelor's degree, master's degree and doctor's degree from Northwestern Polytechnical University in 2014, 2017 and 2022 respectively. He currently works in the Jiangsu University of Science and Technology. He is mainly committed to the theoretical and applied research on low-frequency broadband noise reduction, underwater sound absorption bearing structure and acoustic performance prediction driven by machine learning, and presided over or participated in scientific research projects such as the National Natural Science Foundation of China, the Natural Science Foundation of Jiangsu Province, the Fund for Chinese Doctoral Scholarship, and the Open Project of State Key Laboratory. He published over 20 papers as the first or corresponding author in SCI journals, and served as a reviewer for  journals such as International Journal of Mechanical Sciences, Building and Environment, and Composite Structures.