水下爆炸载荷下阶梯梯度夹芯结构交叉耦合作用的动态响应及失效机理研究

To enhance the blast resistance of lightweight protective structure is the main way to improve the maneuvering and vitality performance of marine vessels subjected to underwater explosion. In order to improve the energy absorption of the core and the blast-resistance performance of metallic sandwich structures, the lab-scaled underwater explosive simulator is going to be used to exert the plane underwater impulsive wave on the step-graded aluminum foam core sandwich structure which shows good properties of lightweight, energy absorption, and functionality in this project. The objective of this project is to investigate the dynamic response and failure mechanism of the step-graded aluminum foam sandwich structure by considering the cross-coupling interaction of the different stages of the dynamic response of sandwich panels. In this project, the interaction between the cavitation evolution and shock wave propagation is captured and studied by performing the visible underwater impulsive experiment, which is used to disclose the mechanism of coupling interaction between the fluid-structure interaction stage and core compression stage of sandwich structures by taking the core compression stage into account. Considering the cavitation effect and step-graded core effect, the analytical model of the transmitted impulse is going to be derived during the first coupling interaction; Then, combing the experimental, theoretical and numerical analysis of dynamic response and associated parameter study of step-graded core sandwich structures, the mechanism of coupling interaction between the core compression stage and structural bending/stretching stage of sandwich structures will be revealed and the analytical model considering the cross-coupling interaction will be developed for the dynamic response the sandwich structure subjected to underwater impulsive loading according to the first and second coupling analysis. The underwater blast resistance and failure mechanism will be studied as well. Based on the analytical model developed in this project, the optimum design model of the step-graded core sandwich structure subjected to underwater impulses is going to be achieved. The achievement of the project is expected to enrich the theory of blast resistance of lightweight protective structures subjected to underwater impulses, and to provide reliable theory basis and technical support in the design of protective structures of marine vessels.

增强轻质防护结构的抗水下爆炸冲击性能是提升舰船机动性能和生存能力的关键所在。本项目提出采用水下爆炸模拟加载装置对轻质、抗冲击吸能性和可设计性强的阶梯梯度泡沫夹芯结构展开研究，以实现金属夹芯结构芯材吸能和结构抗水下爆炸冲击性能的提升。本项目以揭示交叉耦合下阶梯梯度夹芯结构动态响应和失效机理为研究目标，通过可视化水下冲击加载实验，研究冲击波与空化演化的相互作用过程,揭示结构响应的流固耦合阶段和芯材压缩阶段耦合作用机理，建立空化和芯材梯度效应影响下的加载脉冲模型；通过结构动态响应以及相关参数的理论、实验和数值模拟分析，揭示结构响应芯材压缩和整体变形阶段耦合作用机理，建立水下冲击载荷下夹芯结构交叉耦合作用的动态响应理论模型，并揭示夹芯结构抗冲击性能和失效机理，开展阶梯梯度夹芯结构的优化设计。本项目可进一步完善轻质结构抗水下爆炸冲击的理论研究体系，为舰船防护结构的设计提供理论支持和依据。

阶梯梯度夹芯结构是一种可设计性强的结构-功能一体化防护结构。其优异的动态能量吸能性能和轻量化特性，使其作为舰船抗爆炸冲击防护结构的吸能填充材料具有巨大的应用前景，对提升舰船的机动性能和生存能力具有重要作用。本项目以揭示交叉耦合下阶梯梯度夹芯结构动态响应和失效机理为研究目标，通过水下冲击和局部冲击加载实验，结合数值模拟和理论分析，研究了阶梯梯度效应、冲击强度、芯材强度等因素影响下流固耦合引起的空化效应的变化规律，建立了考虑梯度效应和芯材强度的水下冲击加载模型和结构响应理论分析模型。研究了流固耦合加载的非均匀性，得到了夹芯结构芯材结构形式和冲击强度对非常规力学行为的影响规律。研究了高强度局部加载下的阶梯梯度泡沫夹芯结构在冲击强度、边界条件、梯度效应等因素下的动态响应和失效机理，得到了不同影响因素对梯度夹芯结构抗冲击性能的影响机制，获得了夹芯结构参数优化分析的方法。同时还开展了新型的金属和复合材料夹芯结构的不同冲击条件下的研究，得到了不同结构形式的抗冲击吸能机理。本项目进一步完善了轻质结构抗水下爆炸冲击的理论研究体系，为舰船防护结构的设计提供理论支持和依据。