scholarly journals A Refined Theory for Characterizing Adhesion of Elastic Coatings on Rigid Substrates Based on Pressurized Blister Test Methods: Closed-Form Solution and Energy Release Rate

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1788
Author(s):  
Yong-Sheng Lian ◽  
Jun-Yi Sun ◽  
Zhi-Hang Zhao ◽  
Shou-Zhen Li ◽  
Zhou-Lian Zheng
Keyword(s):  
Energy Release Rate ◽  
Closed Form ◽  
Energy Release ◽  
Release Rate ◽  
Closed Form Solution ◽  
Axisymmetric Deformation ◽  
Form Solution ◽  
Refined Theory ◽  
Coating Film ◽  
Delamination Area

Adhesion between coatings and substrates is an important parameter determining the integrity and reliability of film/substrate systems. In this paper, a new and more refined theory for characterizing adhesion between elastic coatings and rigid substrates is developed based on a previously proposed pressurized blister method. A compressed air driven by liquid potential energy is applied to the suspended circular coating film through a circular hole in the substrate, forcing the suspended film to bulge, and then to debond slowly from the edge of the hole as the air pressure intensifies, and finally to form a blister with a certain circular delamination area. The problem from the initially flat coating to the stable blistering film under a prescribed pressure is simplified as a problem of axisymmetric deformation of peripherally fixed and transversely uniformly loaded circular membranes. The adhesion strength depends on the delamination area and is quantified in terms of the energy released on per unit delamination area, the so-called energy release rate. In the present work, the problem of axisymmetric deformation is reformulated with out-of-plane and in-plane equilibrium equations and geometric equations, simultaneously improved, and a new closed-form solution is presented, resulting in the new and more refined adhesion characterization theory.

scholarly journals Closed form solution for the energy release rate and mode partitioning of the single cantilever beam sandwich debond from an elastic foundation analysis

2020 ◽  
pp. 109963622093290
Author(s):  
George A Kardomateas ◽  
Zhangxian Yuan
Keyword(s):  
Energy Release Rate ◽  
Closed Form ◽  
Energy Release ◽  
Elastic Foundation ◽  
Cantilever Beam ◽  
Release Rate ◽  
Closed Form Solution ◽  
Integral Approach ◽  
Sandwich Composite ◽  
Closed Form Expression

The goal of this paper is to derive closed form expressions for the energy release rate and mode partitioning offace/core debonds for the Single Cantilever Beam Sandwich Composite testing configuration, which is loaded with an applied shear force and/or bending moment. This is achieved by an elastic foundation approach, in which a finite length sandwich beam is treated as having a free “debonded” section and a “joined” section where a series of springs exists between the face and the substrate (core and bottom face). The elastic foundation analysis is done for a general asymmetric sandwich construction. A J-integral approach is subsequently used to derive a closed form expression for the energy release rate. It is also shown that the energy release rate is very close to the differential energy stored in the springs at the beginning of the elastic foundation, i.e. the energy released by the “broken” differential spring element as the debond propagates. In the context of this elastic foundation model, a mode partitioning measure is defined based on the transverse and axial displacements at the beginning of the elastic foundation. Since the normal springs account for the transverse compressibility of the core but not for the shear, a correction for the shear of the substrate is included by deriving the expression for the corresponding shear angle and accounting for the additional horizontal “tip” displacement. The results are compared with finite element results for a range of core materials and show very good agreement.

Elastic Foundation Solution for the Energy Release Rate and Mode Partitioning of Face/Core Debonds in Sandwich Composites

2019 ◽  
Vol 86 (12) ◽  
Author(s):  
George A. Kardomateas ◽  
Niels Pichler ◽  
Zhangxian Yuan
Keyword(s):  
Energy Release Rate ◽  
Closed Form ◽  
Energy Release ◽  
Elastic Foundation ◽  
Release Rate ◽  
Sandwich Beam ◽  
Integral Approach ◽  
Closed Form Expression ◽  
Sandwich Composites ◽  
Sandwich Construction

Abstract The goal of this paper is to derive closed form expressions for the energy release rate and mode partitioning of face/core debonds in sandwich composites, which include loading in shear. This is achieved by treating a finite length sandwich beam as having a “debonded” section where the debonded top face and the substrate (core and bottom face) are free and a “joined” section where a series of springs (elastic foundation) exists between the face and the substrate. The elastic foundation analysis is comprehensive and includes the deformation of the substrate part (unlike other elastic foundation studies in the literature) and is done for a general asymmetric sandwich construction. A J-integral approach is subsequently used to derive a closed form expression for the energy release rate. In the context of this elastic foundation model, a mode partitioning approach based on the transverse and axial displacements at the beginning of the elastic foundation (“debond tip”) is proposed. The results are compared with finite element results and show very good agreement.

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