Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China.
Beijing Engineering Research Center of Advanced Elastomers, School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Int J Mol Sci. 2022 Nov 25;23(23):14760. doi: 10.3390/ijms232314760.
Underwater noise pollution, mainly emitted by shipping and ocean infrastructure development of human activities, has produced severe environmental impacts on marine species and seabed habitats. In recent years, a polyurethane-based (PU-based) composite with excellent damping performance has been increasingly utilized as underwater sound absorption material by attaching it to equipment surfaces. As one of the key parameters of damping materials, dynamic mechanical parameters are of vital importance to evaluating the viscoelastic damping property and thus influencing the sound absorption performance. Nevertheless, lots of researchers have not checked thoroughly the relationship and the mechanism of the material dynamic mechanical parameters and its sound absorption performance. In this work, a finite element model was fabricated and verified effectively using acoustic pulse tube tests to investigate the aforementioned issues. The influence of the dynamic mechanical parameters on underwater sound absorption performance was systematically studied with the frequency domain to reveal the mechanism and the relationship between damping properties and the sound absorption of the PU-based composite. The results indicate that the internal friction of the molecular segments and the structure stiffness were the two main contributors of the PU-based composite's consumption of sound energy, and the sound absorption peak and the sound absorption coefficient could be clearly changed by adjusting the dynamic mechanical parameters of the composite. This study will provide helpful guidance to develop the fabrication and engineering applications of the PU-based composite with outstanding underwater sound absorption performance.
水下噪声污染主要由人类活动中的航运和海洋基础设施开发产生，对海洋物种和海底生境造成了严重的环境影响。近年来，一种基于聚氨酯的（PU 基）复合材料因其出色的阻尼性能而被越来越多地用作水下吸声材料，将其附着在设备表面上。作为阻尼材料的关键参数之一，动态力学参数对于评估粘弹性阻尼性能至关重要，从而影响吸声性能。然而，许多研究人员并没有彻底检查材料动态力学参数与其吸声性能之间的关系和机制。在这项工作中，使用声学脉冲管测试有效地制造和验证了有限元模型，以研究上述问题。系统地研究了动态力学参数对水下吸声性能的影响，通过频域揭示了阻尼性能与 PU 基复合材料吸声之间的关系和机制。结果表明，分子链段的内摩擦和结构刚度是 PU 基复合材料耗散声能的两个主要因素，通过调整复合材料的动态力学参数，可以明显改变吸声峰和吸声系数。这项研究将为开发具有优异水下吸声性能的 PU 基复合材料的制造和工程应用提供有益的指导。
