水下爆炸作用下金字塔点阵夹芯结构能量耗散机理研究

The background of this investigation on energy dissipation mechanism of pyramidal lattice truss core sandwich structure subjected to underwater explosion is how to improve the anti-explosion ability of the warship hull structure.Metallic sandwich panels are more effective at resisting underwater blast than monolithic plates at equivalent mass/area.The sandwich panels with a cellular core have the capability of dissipatingconsiderable energy by large plastic deformation under static or dynamic loading. The transmit regularity of shock wave between the fluid and the structure and its influencing factor is going to be studied in this research. The occurrence of soft or strong core behavior is dependent on such factors as the dynamic strength of the core,its thickness and the magnitude of the impulse.The energy absorbers have to sustain intense impact loads, so that their deformation and failure may involve large geometry changes, strain-hardening effects,strain-rate effects and various interactions between different deformation modes such as bending and stretching.The study methods will include analytical investigation,numerical simulation and model experiments.The quasi-static and dynamic constitutive relation of pyramidal truss core sandwich panels will be studied. The interaction between the fluid and the face plate of the sandwich panels,the failure mode of the cores, the absorbing energy ability of structure and the computing methods of the absorbing and dissipating energy of the whole structure are all be studied in this investigation. To explore the failure mechanism of non-contact explosion loading Pyramid sandwich structure under water and energy absorption mode, seeking to influence the energy absorption was the main factor of sandwich structure, provides the basis for the design and effectiveness evaluation of warship broadside protective structure under water, and provide reference for other forms of underwater explosion protection structure research.

水下爆炸载荷作用下金字塔点阵夹芯结构能量耗散机理研究，是以提高大型舰艇舷侧水下抗爆防护能力为背景，提出在防护结构中加入夹芯结构的元素。本项目以冲击载荷在结构中的传递规律、结构对冲击能量的吸收和耗散为中心，以理论分析和数值模拟为主要手段，辅助以必要的试验验证，分别研究金字塔点阵结构的准静态、动态本构关系，夹芯板面板与冲击波载荷之间的流体-结构作用规律，金字塔点阵结构芯材的失效模式和吸能计算，夹芯结构整体的吸能、耗能计算方法等问题，建立反映夹芯结构宏观等效力学参数与单元微结构参数之间的关系的本构模型、考虑芯材特性影响的流固耦合分析模型、芯材失效模型、面板和芯材吸能分析模型，探索水下非接触爆炸载荷作用下金字塔点阵夹芯结构的失效机理和吸能模式，寻求影响夹芯结构吸能得主要因素，为舰艇舷侧水下防护结构的设计和效能评估提供依据，为其他形式的水下抗爆防护结构研究提供参考。

本项目主要针对金字塔点阵夹芯板结构的缓冲耗能机理开展了研究。.载荷和结构等效本构关系是整个研究的基础，课题组首先对水下爆炸载荷和金字塔点阵夹芯结构准静态和动态等效本构关系开展了。在载荷方面主要研究边界条件对水下爆炸气泡运动特性的影响，通过仿真研究得到了不同边界条件下球形气泡假设的适用条件。在结构等效本构关系方面，通过对金字塔点阵夹芯板单元结构的准静态压缩力学性能和动态力学性能理论研究，充分认识了微结构与性能之间的关系，达到通过单元结构来预测复合壳板整体力学性能的目的，并通过试验对理论结果进行了验证。.根据夹芯板结构在水下近距爆炸冲击下损伤响应的特点，将其分为流固耦合、夹芯坍塌和整体变形三个阶段。弄清了夹芯板结构在水下近距爆炸冲击载荷作用下的流固耦合效应和冲击能量的缓冲耗散过程，提出了金字塔点阵夹芯板结构在水下近距爆炸冲击载荷作用下动态响应的理论计算方法。通过金字塔点阵夹芯板结构在水下近距爆炸冲击试验对其缓冲耗能机理进行了研究，并与理论结果进行了对比，发现二者吻合的较好，验证了理论计算方法的正确性。.为研究在爆炸载荷作用下防护结构的抗爆能力和吸能机理，对实心板和夹芯板模型的响应过程进行了仿真计算。仿真结果显示单元类型对结果影响不大；相同工况下夹芯板结构前面板变形大于实心板，后面板变形小于实心板；外载荷对夹芯板所做的功主要转变为动能和塑性变形能，以塑性变形能为主，夹芯板塑性吸能能力明显大于实心，在一定范围内随着爆炸载荷增大，优势更为明显。通过对不同水下爆炸工况下板金字塔点阵夹芯板结构缓冲耗能规律的研究，得到芯层强度与吸收冲量的关系、芯层吸能量与结构参数的关系和面板变形与水爆冲量的关系。.新型点阵夹芯夹芯板结构是一种新型轻质高强多功能材料，在减轻船舶结构重量，提高舰艇耐撞性能和结构抗爆炸冲击性能上有着广泛的应用前景，本项目的研究成果可以为新型复合壳板的水下抗爆设计提供支持。