A rate-dependent cohesive zone model for adhesive damage considering fibrillation

Abstract

The pressure-sensitive adhesive (PSA) has been widely utilized in engineering and biomedicine fields. It is known the fibrillation process of PSA can considerably increase the adhesive energy, which significantly affects its adhesive behavior. Since the classical bilinear cohesive zone model (CZM) did not account for the fibril evolution, this paper aims to propose a rate-dependent CZM based on the physical mechanism of fibrillation to describe the cohesive failure of PSA. The multilinear traction-separation law (TSL) was established accordingly, including homogeneous deformation, cavity nucleation and dilatation, and fibril evolution. After being implemented into the FE software using a user-subroutine UMAT, the proposed CZM was validated by experimental data from probe-tack tests and then was utilized to investigate the effect of loading rate on PSA's adhesive performance of the peeling test. By examining the fibril's strain rate distribution using the proposed CZM, it is possible to correlate the PSA's adhesive performance under 90° peeling tests and the probe-tack test, thereby compensating for the theoretical prediction's inaccuracy due to the assumption of constant strain rate. It demonstrates the proposed CZM is a promising approach to investigating the rate-dependent cohesive failure of PSA considering fibrillation.