粘弹性材料力学参数的宽频带测试与动态参数建模研究

Characterizing the behavior of viscoelastic materials and their visco-elastic properties subject to under-water ambient presure and temperature changes is crucial in under-water acoustic stealth technology. This proposal aims to develop a more accurate approach that is also applicable in a wider frequency range to extract the complex modulus and loss factor of viscoelastic materials. Specifically, an impulse method that was originally developed and has been validated by the principle applicant for airborne noise applications will be extended to measure the complex modulus and loss factor of viscoelastic materials by utilizing the longitudinal vibration testing over a wide frequency range. To facilitate the study, the propagation of an impulse wavefront along a one dimensional visoelastic rod will be investigated theoretically and experimentally, in which the geometric and material dispersion phenomena will be the focus. Then, a parametric model that incorporates the ambient pressure and temperature etc into the equation for complex -modulus will be developed to give a thorough description of the dynamic behavior of viscoelastic materials subject to environment condition changes. The dynamic parametric will be used to design the viscoelastic material with excellent acoustic properties under any ambient conditions.

研制开发耐水压高、温度适应性好、宽频带声学性能优良的粘弹性材料是声隐身技术的关键，其核心问题是对材料动态力学参数的掌握和声学优化设计。本项目研究材料力学参数宽频带测试方法，建立包含温度和压强因子的力学参数模型。深入分析粘弹性细棒中脉冲压力波传播规律，解决脉冲波几何频散、材料频散和横波干扰等关键科学问题，改善力学参数在中高频段的测试精度；在自由体积理论时温等效方程的基础上推导不同参考温度下有压强修正的WLF方程，由测量数据确定转移因子和松弛因子等模型参数，得到包含温度和压强因子的H-N参数模型，该模型可以对测试频率范围外特定温度和压强条件的力学参数进行预测。在此基础上，给出满足声学性能指标的、适用于大范围温度和压强条件的粘弹性材料选型要求。通过以上研究，解决力学参数宽带精确测试的关键技术问题，掌握粘弹性材料在复杂温度和压强条件下动态力学参数变化规律，为水声材料设计与声学性能优化提供理论依据。

针对水声覆盖层设计时对粘弹性材料中、高频范围动态力学参数精确掌握的需求，本项目开展了力学参数宽频测试和动态参数建模的研究。深入研究了粘弹性细棒中脉冲纵波传播规律，提出了脉冲纵波测试时直达波提取方法，有效地解决了力学参数宽频带测试问题。建立了包含温度和压强因子的动态力学参数模型，可实现对特定温度和压强条件、宽频带范围的材料力学参数预测；利用储能模量、损耗因子与吸声系数之间的关系，给出了由动态力学参数评估材料声学性能的方法。开展了基于超材料的低频声学覆盖层设计工作。研制了一套可调压的力学参数宽频带测试实验系统。项目研究成果可用于粘弹性材料中高频力学参数测试、声学性能评估等方面，对声学覆盖层设计有重要的参考价值。结合项目研究，完成博士论文2篇、正在进行3篇；完成硕士论文5篇、正在进行1篇。已发表学术论文39篇，其中SCI索引14篇、EI索引18篇。项目圆满完成了计划书提出的研究内容、达到了预期的研究目标，取得了显著的研究成果。