Analysis on adhesive contact of micro-columns

This paper analyzes the contact and adhesion between a rigid hemisphere and micro-columns on a substrate. We establish two types of three-dimensional finite element models for the analysis. One uses continuum elements and the other uses spring elements to describe the mechanical behavior of the micro-columns. In the analysis of adhesive contact, the adhesive stress between the surfaces of micro-columns and hemisphere was implemented by a user-defined cohesive element. The validation of the spring element model is tested by comparing the simulation results with those of the continuum element model. The influences of the aspect ratio, column width, and area density of micro-columns and substrate thickness on the effective Young's modulus are discussed, as well as the maximum pull-off force and effective work of adhesion. The numerical results agree mostly with the experimental data in the literature. The comparison also shows that the simple analysis by Hui et al. predicts the effects of micro-columns on effective work of adhesion quite well.