可恢复双稳态多孔覆盖层在水下爆炸载荷下的抗爆机理研究

The rubber or foam coatings plastered onto the hull of warships have been proved to be very effective in mitigating the water blast. Still, the mechanism of energy absorption of rubber coating is viscous effect and loading rate - dependent, and the foam coating is plastic deformation which is unrecoverable. To overcome such weakness, this project propose a new coating based on the bistable property of the buckling beam which has two merits: one is that the energy absorption mechanism stems solely from the structural geometry of the beam elements, the other is that the mechanical response is reversible and repeatable. The dynamic nonlinear fluid-structural interaction model which can consider the buckling deformation of coatings and dynamic response of water is built. The loading characteristics due to cavitation phenomenon and fluid-structural interaction are analyzed. The mechanism of energy absorption of coating is obtained based on the bulking mechanism of bistable beam. Additionally, we will conduct shock tube experiment and water tank experiment to reveal the shock mitigation mechanism and effect of the coating. The research results can provide theoretical basis and technical support for coatings design and optimization of warships subjected to underwater explosion.

在舰艇壳体湿表面敷设橡胶多孔或塑性泡沫抗冲覆盖层能有效降低舰艇水下爆炸响应。但是，前者基于率相关粘性效应耗能且吸能效果有限，后者通过塑性变形耗能不可重复利用。为克服上述缺点，项目提出了一种可恢复双稳态多孔抗冲覆盖层，该覆盖层基于双稳态梁屈曲时的锁能特性，具有吸能特性由结构几何特征主导、变形可恢复的优点。项目围绕可恢复双稳态多孔覆盖层结构受水下爆炸时的屈曲大变形动响应及流体空化演化机制，通过建立非线性流-固耦合冲击动力学模型，分析流体空化的发生、扩展、溃灭过程及流体与固体耦合效应综合作用下湿表面真实冲击载荷特征，明确覆盖层动屈曲特性及冲击波在覆盖层中的传递机制，获取覆盖层-壳板复合结构瞬态大变形响应特征及变形锁能机制，并结合水中激波管及敷设覆盖层圆板水箱爆炸试验，给出可恢复双稳态多孔覆盖层的抗爆机理和防护效果，建立覆盖层设计准则，为舰艇水下爆炸防护结构设计及优化提供理论依据和技术支撑。

可恢复双稳态抗冲覆盖层结构是一种新型冲击防护结构，它兼具塑性防护结构的吸能特性及变形可恢复的双重优点。使其具有作为舰艇新型抗冲覆盖层的良好应用前景。本项目以揭示新型双稳态抗冲覆盖层防护机理和防护效果为目标，建立了双稳态梁单胞屈曲理论模型；研究了单曲梁及双曲梁具有双稳态特性的条件；揭示了曲梁特性参数变化对其力学特性及双稳态特性的影响规律。建立了由双稳态梁构成的多层双稳态抗冲覆盖层结构的等效质量-非线性弹簧力学分析模型及冲击动力学模型，获得了双稳态抗冲覆盖层的等效力学模型、变形模式及吸能机制。建立了考虑覆盖层大变形的流固耦合及空化一维理论模型及三维数值模型，揭示了不同边界条件对流固耦合及流体空化演化的影响规律，获得了覆盖层大变形中流固耦合及流体空化载荷。基于已有中远场及近场水下爆炸试验结果，验证了水下爆炸数值模型的有效性，并在此基础上上，研究了抗冲覆盖层力学特性、敷设位置等对冲击防护效果的影响规律，建立了抗冲覆盖层的设计准则。本项目进一步完善了舰船抗冲覆盖层的抗水下爆炸冲击的理论研究体系，为舰船新型防护结构设计提供理论支撑和参考。