粘附动物的末端脚趾具有刚柔耦合的特征,它们的结构-功能关系是理解生物启发粘附系统和仿生粘附单元设计中亟待解决的问题。在本文中,灵感来自壁虎脚趾的刚柔耦合粘合系统,设计了一种刚柔耦合粘接单元,测试了粘合剂在不同预载荷下的界面强度,建立了刚柔耦合粘接单元压缩剥离过程的模型和分析方法。同时,结合实验测试,研究了刚-柔性结构的耦合机理对粘合单元压缩和剥离过程中界面应力和最终剥离力的影响。研究发现,在特定范围内,粘合单元的长度L对系统的法向剥离力没有明显影响,并且法向剥离力随着压缩力P的增大而线性增大;而粘合单元的倾角θ0和刚性背衬层hb的厚度对系统最终法向剥离力的影响呈现非线性特征,当粘合单元的倾斜角θ0为5°时,刚性背衬层hb的厚度为0.2mm或0.3mm,法向剥离力和粘附力与预加载系统的比率达到最大值。与柔性粘合单元相比,在相同的压缩过程中,由刚性-柔性耦合粘合单元形成的压缩区域增加了6.7倍,在相同的剥离力下,剥离区增加了8倍,剥离端最大法向拉应力下降了20倍。刚柔耦合力学提高了压缩和剥离过程中接触应力的均匀性。研究结果为刚柔耦合粘接单元的设计提供了指导,进一步提供具有刚柔耦合仿生设计的仿生爬壁机器人的末端执行器。
The terminal toes of adhesive animals are characterized by rigid-flexible coupling, and their structure-function relationship is an urgent problem to be solved in understanding bioinspired adhesive systems and the design of biomimetic adhesive units. In this paper, inspired by the rigid-flexible coupling adhesive system of the gecko toe, a rigid-flexible coupling adhesive unit was designed, the interface strength of the adhesives under different preloads was tested, and the model and analysis method of the compression and
peeling process of the rigid-flexible coupling adhesive unit was established. Meanwhile, combined with the experimental test, the effect of the coupling mechanism of the rigid-flexible structure on the interfacial stress and the final
peeling force during the compression and
peeling process of the adhesive unit was studied. The research found that the length of the adhesive unit L has no apparent effect on the normal peel force of the system within a specific range, and the normal
peeling force increases linearly with the increase in the compression force P; while the influence of the inclination angle θ0 of the adhesive unit and the thickness of the rigid backing layer hb on the final normal peeling force of the system presents nonlinear characteristics, when the inclination angle θ0 of the adhesive unit is 5°, and the thickness of the rigid backing layer hb is 0.2 mm or 0.3 mm, the normal peel force and the ratio of adhesion force to preload the system reaches its maximum value. Compared with the flexible adhesive unit, the compressed zone formed by the rigid-flexible coupling adhesive unit during the same compression process increased by 6.7 times, while under the same peeling force, the peel zone increased by 8 times, and the maximum normal tensile stress at the
peeling end decreased by 20 times. The rigid-flexible coupling mechanics improves the uniformity of the contact stress during the compression and peeling process. The research results provide guidelines for the design of the rigid-flexible coupling adhesive unit, further providing the end effector of the bionic wall-climbing robot with a rigid-flexible coupled bionic design.