Numerical simulation of the edge stress singularity and the adhesion strength for compliant mushroom fibrils adhered to rigid substrates
Numerical simulation of the edge stress singularity and the adhesion strength for compliant mushroom fibrils adhered to rigid substrates
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DOI：
10.1016/j.ijsolstr.2016.02.018
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发表时间：
2016-05-15
影响因子：
3.6
通讯作者：
Arzt, E.
中科院分区：
文献类型：
--
作者：
Balijepalli, R. G.;Begley, M. R.;Arzt, E.
由于分子间相互作用而产生的微图案表面的仿生粘附在过去十年中引起了广泛的研究兴趣。实验表明，顺应的“蘑菇”形原纤维可实现最佳粘附力。本文对不同蘑菇形状对刚性基材粘附力的影响进行了数值分析。当远程应力施加在与刚性基材完美粘合的原纤维的自由端时，发现沿着原纤维的合成应力分布在直冲头和蘑菇原纤维之间发生显着变化。在原纤维接触基底的边缘存在奇异应力场，在这项工作中，评估了完美粘合到平坦基底的原纤维的奇异性振幅，以便在那里不会发生滑动。这项练习是针对涉及蘑菇盖不同直径和厚度组合的原纤维几何形状进行的。通过假设应力奇异点所在拐角处预先存在的脱离长度，我们预测了各种蘑菇帽形状的粘合强度。我们的研究表明，较小的茎直径和较薄的蘑菇盖会导致较高的粘合强度。还给出了其他形状的有限数量的结果，包括那些具有将茎连接到帽的圆角半径的形状。结果支持合成微图案粘合剂的合理优化。 (c) 2016 年作者。由爱思唯尔有限公司出版
Bio-inspired adhesion of micropatterned surfaces due to intermolecular interactions has attracted much research interest over the last decade. Experiments show that the best adhesion is achieved with compliant "mushroom"-shaped fibrils. This paper analyses numerically the effects of different mushroom shapes on adhesion to a rigid substrate. When a remote stress is applied on the free end of a fibril perfectly bonded to a rigid substrate, the resultant stress distribution along the fibril is found to change dramatically between the straight punch and mushroom fibrils. A singular stress field is present at the edge of the fibril where it contacts the substrate and, in this work, the amplitude of the singularity is evaluated for fibrils perfectly bonded to a flat substrate so that sliding cannot occur there. This exercise is carried out for fibril geometries involving combinations of different diameters and thicknesses of the mushroom cap. By assuming a pre-existing detachment length at the corner where the stress singularity lies, we predict the adhesive strength for various mushroom cap shapes. Our study shows that a smaller stalk diameter and a thinner mushroom cap lead to higher adhesive strengths. A limited number of results are also given for other shapes, including those having a fillet radius connecting the stalk to the cap. The results support the rational optimisation of synthetic micropatterned adhesives. (c) 2016 The Authors. Published by Elsevier Ltd.