石墨烯的抗侵彻性能和破坏机理研究

The study on the penetration of materials and structures has significant scientific interests and engineering values for developing outstanding ballistic performance materials. Recent studies have shown that layered nano-materials have distinguished anti-penetration properties. The specific penetration energy for multilayer graphene is about 10 times more than the values of macroscopic steel sheets in same conditions. However the related damage mechanism is still not clear right now. Aiming at the key problem, we will mainly carry out following study: (1) the influence of the thickness of targets as the numbers of the layers of graphene, the characteristics of the stress wave propagation and the energy absorption, (2) the ballistic performance of graphene, defected graphene and polycrystalline graphene oblique impacted by projectiles with different velocities and mass, (3) the temperatures effects and the behavior of dynamic crack propagation. Focus will be paid on the failure mode and the energy dissipation of graphene impacted by projectiles. Our previous experience in the failure of graphene can ensure the successful completion of this project. These investigations will have significant scientific interests in understanding the anti-penetration properties of graphene, and inventing outstanding ballistic performance materials.

研发高性能的抗侵彻材料和结构，并探索其相应的破坏机理具有重要的科学意义和应用价值。新近的研究表明，层状纳米材料具有优异的抗侵彻性能，多层石墨烯对弹体的比能量吸收是同样条件下钢片对弹体的比能量吸收的十倍。然而，目前对其破坏机制尚不清楚，针对其中最关键的科学问题，本项目拟主要开展以下工作：（1）靶体的厚度（即石墨烯层数）对石墨烯抗侵彻性能的影响，揭示应力波在多层石墨烯间传播和吸收弹体能量的物理机理和定量规律；（2）弹体入射角的影响，石墨烯、含缺陷石墨烯和多晶石墨烯在不同速度和质量弹体倾斜撞击下的响应；（3）石墨烯受弹体高速碰撞侵彻时裂纹的发生和动态扩展特征，并考察温度效应。着重关注石墨烯受侵彻时的破坏模式和能量吸收耗散机理。申请者已在石墨烯破坏力学方面有较好的研究基础和前期积累，能确保本项目的完成。项目预期成果能加深对石墨烯的抗侵彻性能和破坏机理的认识，促进高性能抗侵彻纳米材料和结构的研发。

大到航天器小到头盔，多胞抗冲击吸能材料(EAMs)在各领域都有广泛应用价值，研发性能更优的抗冲击吸能材料有着广泛的工程需求。泡沫铝、泡沫钢、多胞金属玻璃和碳纳米管巴基纸等常见多胞吸能材料的抗冲击吸能量级为1-100 J/g。本论文研究发现基于石墨烯的三维蜂窝结构面内的抗冲击比能量吸收达到2400 J/g，远高于前面提到的多胞材料。其面外抗侵彻比能量吸收能与石墨烯相当达到3400 J/g，是钢材的十倍。石墨烯三维蜂窝材料超强的比能量吸收能力，宏观上是由于其很长的平台应变区及高达2 GPa的平台应力，细观机理上是源于其晶体结构由高能的sp2和sp3碳-碳化学键相互链接组成。本文的发现为工程设计更优异轻质的吸能系统提供了理论基础。另外，研究了温度对石墨烯弯曲刚度的影响，对石墨烯等二维纳米材料的应用提供理论基础。