新型梯度负泊松比多孔夹芯复合结构在强动载荷下的力学行为及失效机理

The applications for novel graded sandwich composite structures with negative Poisson’s ratio (NPR) cellular cores in advanced defense technology, such as protective structures, aeronautics, astronautics and bridge constructions, will highly meet its multi-functional demands, especially for lightweightness, high strength, good impact resistance, high stability. Experiments, numerical simulations and theoretical analysis would be employed to systematically study the mechanical behavior and failure mechanism of novel graded sandwich composite structures with NPR cellular cores under intensively dynamic loading. Several challenging problems will be solved:1) investigate the dynamic deformations and failure modes, and compare its intrinsic energy dissipation and failure mechanism for each component in the sandwich structure; 2) establish the analytical model of the responses under intensively dynamic loading; 3) obtain the optimal topology and carrying capacity of the sandwich structure when the highest impact resistance will be determined by changing the geometrical parameters such as thickness ratio of face to core and cell topology, or material parameters such as relative density of the core and graded configurations in the structure; 4) build the constitutive model for graded NPR honeycombs/foams in the condition of high strain rate, to understand the propagation characteristics and attenuation rules of stress wave. We believe that the implementation for this project will pave the way for the scientific research of novel graded sandwich composite structures with NPR cellular cores, and more importantly, will also help to promote its engineering applications in major national projects.

新型梯度负泊松比多孔夹芯复合结构应用于防护结构、航空航天、桥梁建筑等国防高新技术领域将更好地满足其对轻质、高强、抗冲击、高稳定性等多功能集成结构的需求。本课题以此为依托，旨在通过实验研究、数值模拟和理论分析相结合的方法，系统地研究新型梯度负泊松比蜂窝/泡沫夹芯复合结构在强动载荷下的力学行为和失效机理：1）分析其动态变形和失效模式，对比各组分的能量耗散机理和破坏机制；2）建立和完善其在强冲击载荷下的塑性响应分析模型；3）通过优化面板/芯层相对厚度和胞元拓扑等几何参数、以及芯层相对密度和梯度配置等材料参数，给出一定质量下抗冲击性能最强的夹芯结构的最优拓扑和最佳承载范围； 4）建立和完善梯度负泊松比蜂窝/泡沫高应变率下的本构分析模型，阐述应力波的传播特征和衰减规律。该课题的顺利实施将在一定程度上推动负泊松比夹芯复合结构在国家重大工程中的应用并为其科学研究提供必要的理论指导。

新型负泊松比材料和结构在防护结构、航空航天、桥梁建筑等国防高新技术领域能更好的满足满足材料轻质、高强、抗冲击、高稳定性等多功能集成结构的需求。该项目围绕重大国防和民生工程中的结构防护和能量吸收这一关键问题，采用实验研究、数值模拟和理论分析相结合的方法，以负泊松比蜂窝、梯度蜂窝、Ziga-zag origami、负泊松比管和梁等新型负泊松比材料和结构为研究对象，系统开展了(1）负泊松比材料的本构关系和应力波的传播；(2）负泊松比复合结构在强动载荷作用下的塑性动力学行为。揭示了负泊松比材料在准静态和动态载荷下的变形行为和应力波传播规律，以及负泊松比复合结构的塑性大变形和能量吸收响应情况。相关研究结果加深、丰富与扩展了冲击动力学的相关理论，为重大国防和民生工程的安全防护提供了重要的理论基础与技术支撑，尤其在耗能材料和防护结构的设计、制造、表征和评估方面意义重大。