Effect of grain boundaries (GBs) on elastic shock wave in graphene is investigated by molecular dynamics simulations. Bicrystal graphenes with symmetrical GB are shocked along directions perpendicular and parallel to GB. For perpendicular shock loadings, double elastic shock waves emerge in form of quasilongitudinal (QL) and quasitransverse (QT) waves, since the loading direction is neither zigzag nor armchair. GB attenuates the QL wave and gives rise to new QT waves propagating into grains. Transverse particle motion in the elastic shocks can induce small lattice rotations and different oriented regions, whose number increases upon the passage of waves through GB. Upon shock loadings along GB, transverse particle motions of opposite direction generate in the two grains, and change the pressure distribution right behind wavefront, and then result in deviation of shock wave from planar loading or “V” shaped wavefront turning at GB. The above phenomena are attributed to the turn of grain orientation at GB and transverse particle motions induced by lattice symmetry reduction upon shock compression.

通过分子动力学模拟研究了晶界 (GB) 对石墨烯中弹性冲击波的影响。具有对称 GB 的双晶石墨烯沿垂直和平行于 GB 的方向受到冲击。对于垂直冲击载荷，双弹性冲击波以准纵向 (QL) 和准横向 (QT) 波的形式出现，因为载荷方向既不是锯齿形也不是扶手椅。GB 衰减 QL 波并产生传播到颗粒中的新 QT 波。弹性冲击中的横向粒子运动可以引起小的晶格旋转和不同取向的区域，其数量随着波通过 GB 而增加。在沿 GB 的冲击载荷下，两个晶粒中产生相反方向的横向粒子运动，并改变波前正后方的压力分布，进而导致冲击波偏离平面载荷或“V”形波前转向GB。上述现象归因于GB处晶粒取向的转变和冲击压缩时晶格对称性降低引起的横向粒子运动。