剪切流剥离粘附弹性片的剥离阈值
Peeling threshold for removal of an adhered elastic sheet by a shear flow
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中文总结 AI 辅助
本研究通过实验与Griffith断裂理论分析，发现中等粘附强度下剪切流剥离弹性薄片的临界剪切速率约为$B/(ηL^3)$，且几乎与粘附能无关，该结果可助力二维材料规模化制备。
中文摘要 AI 辅助
流体剪切可导致粘附在平坦基底上的弹性薄片发生剥离，该剥离过程在各类环境系统与技术系统中均具有重要意义。剥离条件取决于以下参数：剪切速率$\boldsymbol{\u0307γ}$、流体黏度$η$、薄片已剥离部分的长度$L$、弯曲刚度$B$以及粘附能$Γ$。那么控制剥离过程的规律是什么？我们针对中等粘附强度的情形开展了实验研究，实验采用粘接在基底上的宏观薄片，将其置于盛有黏性流体的剪切池内。实验结果表明，发生剥离的临界剪切速率量级为$\boldsymbol{\u0307γ} \thicksim B/(ηL^3)$，出乎意料的是，该阈值与粘附能无关。我们将Griffith断裂理论应用于薄片形貌的光学测量数据，分别在剥离前沿自由移动和边界夹持两种条件下对该结果进行了理论阐释。结果显示，当剪切速率满足$\boldsymbol{\u0307γ} \thicksim B/(ηL^3)$时，薄片的大曲率会使应变能释放率在该阈值处近乎发散，这种近似发散特性进而导致剥离阈值对$Γ$的依赖程度极弱，验证了近期提出的一项理论（Salussolia等人，《Journal of the Mechanics and Physics of Solids》，2020年，第134卷）。除其他应用外，本研究提出的定量公式可为石墨烯等二维材料的规模化制备提供助力。
英文摘要
Fluid shear can induce detachment of a thin elastic sheet adhered to a flat substrate. This peeling process is important in a variety of environmental and technological systems. The condition for peeling depends on: the shear rate $\dotγ$, the fluid viscosity $η$, the length of the detached portion of the sheet $L$, the bending rigidity $B$ and the adhesion energy $Γ$. What are the laws governing the detachment? We address this question experimentally in the regime of intermediate adhesion, using macroscopic sheets bonded to a substrate and immersed in a shear cell containing a viscous fluid. The experiments indicate a critical shear rate for peeling of the order of $\dotγ \sim B/(ηL^3)$. This threshold is, unexpectedly, independent of adhesion. We rationalise this result by applying Griffith's fracture theory to optical measurement data of the shape of the sheet, under conditions of freely moving peeling front or clamped boundary. The results indicate that the large curvature of the sheet for $\dotγ \sim B/(ηL^3)$ yields a nearly diverging strain energy release rate at this threshold. This approximate divergence in turn yields a peeling threshold that depends at most weakly on $Γ$, confirming a theory that was proposed recently (Salussolia et al., J. Mech. Phys. Solids, 2020, 134). Among other applications, our work provides a quantitative formula that can aid the production at scale of 2D materials such as graphene.
发表机构
- Process and Energy Department, 3ME Faculty of Mechanical, Maritime and Materials Engineering（过程与能源系，3ME机械、海事与材料工程学院）
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