Effect of confinement and interfacial adhesion on peeling of a flexible plate from an elastomeric layer

Abstract

a b s t r a c tThe finite element method and a cohesive zone model are used to analyze plane strain interfacial debonding of an elastomeric layer from an overhanging deformable plate when it is peeled off by applying a normal displacement at the edge of the overhang. The commercial software, ABAQUS, is employed in this work that is focused on understanding the collective role of the following two non-dimensional parameters: (i) the confinement parameter, α, defined in terms of the flexural rigidity of the plate, and the modulus and the thickness of the interlayer, and (ii) the adhesion parameter, φ, defined in terms of the cohesive zone parameters and the modulus to thickness ratio of the interlayer. The interfacial adhesion is characterized by a bilinear traction-separation (TS) relation. Numerical experiments reveal that when α is greater than α c , damage initiates at an interior point on the interface and at the interface corner on the traction-free edge irrespective of the value of φ. However, φ must be greater than φ c for the debonding to become wavy/undulatory. The critical value, φ c , of the adhesion parameter agrees with the necessary condition found in our previous work on debonding of an elastomeric layer from a rigid block when it is uniformly pulled outward. For α < α c , damage/debonding initiates only from the interface corner, and no wavy debonding ensues. The peak peeling force prior to the initiation of an internal debond is found to be a monotonically increasing function of φ/ α, suggesting its potential use as a design variable and as a guide for determining the TS parameters. Results of a few additional numerical experiments in which the elastomeric layer can debond from both adherends provide insights into designing a demolding process for a sandwiched elastomeric layer.

Edge Debonding in Peeling of a Thin Flexible Plate From an Elastomer Layer: A Cohesive Zone Model Analysis

“…As expected for the bending of a plate on an elastomer foundation, the plate deflection exhibits decaying oscillatory distribution. The computed deflection profile agrees well with that reported by Ghatak et al [8] and with that numerically computed using the finite element method (FEM) [27]. Plots of the spatial distribution of the peel stress exhibited in Fig.…”

“…The point with the maximum peel stress, T=T c ¼ 1, in the present work is the tip of the CZ, with the value of T c regarded as an intrinsic property of the pair of interacting materials. The presently predicted peel stress distribution at D A ¼ 4:0 agrees reasonably well with that computed using the FEM [27] with the FEM predicting 0.6% smaller traction-free length A and 24% smaller CZ length D than that given by the current approximate analysis. These differences are possibly due to using the lubrication theory, neglecting shearing deformations of the plate and other approximations made in the present work.…”

“…One can see that D 0 increases (decreases) with an increase in g s (A 0 ), Fig. 4 Comparisons of predicted peel stresses from present work with those predicted by the LEFM [8] solution and computed using the FEM [27]. The nondimensional input parameters are listed in the insets.…”

“…The length scale b À1 is related to the deformability of the interlayer [6,8] relative to that of the flexible plate, a represents the geometric confinement [27] and equals the ratio of the bending stiffness of the plate to that of the interlayer, and / is an adhesion parameter that dictates the CZ size [9,27].…”

“…9 as a function of g s for A 0 ¼ 2:83 and compared with those from the numerical solution of the plane strain problem using the FEM [27] for edge debonding mechanism. One can observe that the predicted pull-off force values decrease with an increase in g s relatively faster for g s > 1.3, while for smaller values of g s , they follow a scaling similar to that of the LEFM predictions.…”