Stretching and debonding of adhesive fibril

In pressure-sensitive adhesive (PSA) tapes, adhesive failure is often accompanied by cavitation and fibrillation. In this paper, we focus specifically on fibrillation. We model the behavior using a single fibril (mono-fibril) configuration with the axisymmetric boundary conditions. Using the finite element method, we simulate the mono-fibril with varying aspect ratios using hyperelastic models such as Arruda-Boyce and Yeoh. First, we explain why the deformation of these fibrils is not purely uniaxial. We then analyze the normalized force-stretch response using appropriate scaling models. Then we examine the impact of changing strain-hardening, inter-fibrillar distance, and bulk modulus on the fibril response. Following this, we investigate fibril debonding using parameters of the Yeoh model fitted to the uniaxial rheological experimental data from two PSA tapes, referred to as PSA types 6A and 6B. Based on this analysis, we derive the power laws for debonding stretch and debonding force for both PSA types. Finally, we compare our findings with experimental data on mono-fibril debonding from the literature.