水下强冲击波载荷下分层梯度覆盖层的近壁面流体空化机理及其防护效能研究

The flexible coatings plastered onto the hull of warships have been proved to be very effective in mitigating the water blast. Still, the shock resistance capability of such coatings can be improved by introducing graded coatings, where the material properties of the coatings along the primary direction of shock wave propagation can be designed and controlled. Based on the background, this project focuses on the transient shock response and shock mitigation mechanism of graded coatings subjected to near-field underwater explosion. The dynamic model which can consider the plastic deformation of graded coatings and coupling effects of gas, water and solid will be established by using a numerical solver that couples discontinuous Galerkin method and finite element method. According to the dynamic model, the relationship between the coatings’ gradation and cavitation evolution, the incident shock wave at the fluid-structure interface, the material compression and elastic-plastic stress wave transmission mechanism of the graded coatings at different period of time will be revealed. Additionally, we will conduct one-dimensional shock tube experiment and water tank experiment. Finally, we can obtain the shock mitigation effects of graded coatings with different core gradation under different shock loading by combing the numerical and experimental results. The research results can provide theoretical basis and technical support for coatings design and optimization of warships subjected to underwater explosion.

前期研究表明敷设于船体外板湿表面的均匀吸能覆盖层对水下爆炸具有良好的防护效果。在此基础上通过剪裁覆盖层芯层吸能体以形成分层梯度结构，有望从降低爆炸波冲量和提高芯层吸能效率两方面进一步提升其防护效能。项目围绕水下强冲击波作用下分层梯度覆盖层-壳板复合结构的瞬态大变形响应机制及非线性流固耦合效应开展研究，建立基于间断迦辽金-有限元混合方法考虑流体介质瞬态空化及梯度芯层动塑性响应的液-固耦合爆炸力学模型，分析不同芯层材料梯度分布下近壁面流体的空化起始、扩展及闭合过程及引起的冲击波加载机制，获取分层梯度覆盖层-壳板复合结构在不同加载特征下的瞬态大变形响应特征，并结合橡胶-聚氨酯样品的激波管及水箱爆炸试验，明确分层梯度覆盖层对水下强冲击波的防护机理，建立特定爆炸载荷下芯层梯度分布特征与覆盖层对壳板结构防护效能之间的内在规律，为舰艇的水下爆炸防护设计提供理论依据和技术支撑。

项目围绕一种敷设于船体外板湿表面具有分层梯度吸能芯层的覆盖层为对象，重点围绕其水下爆炸响应及防护特性开展了理论与试验研究。首先，围绕水下强冲击波作用下分层梯度覆盖层-壳板复合结构的瞬态大变形响应机制及非线性流固耦合效应开展研究，建立基于间断迦辽金-有限元混合方法考虑流体介质瞬态空化及梯度芯层动塑性响应的液-固耦合爆炸力学模型；然后针对覆盖层不同的分层形式，分析了不同芯层材料梯度分布下近壁面流体的空化起始、扩展及闭合过程及引起的冲击波加载机制；结合橡胶-聚氨酯样品的水箱爆炸试验及半圆柱壳体的水池爆炸试验，明确分层梯度覆盖层对水下强冲击波的防护机理，建立特定爆炸载荷下芯层梯度分布特征与覆盖层对壳板结构防护效能之间的内在规律。项目的研究成果可为舰艇的水下爆炸防护设计提供理论依据和技术支撑。