Materials Science and Engineering A 390 (2005) 385–392 A parametric study of a pressurized blister test for an elastic–plastic film-rigid substrate system K. Hbaieb a,∗ , Y.W. Zhang b a Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602, Singapore b Department of Materials Science, National University of Singapore, 10 Kent Ridge Cresent, Singapore 119260, Singapore Received 31 March 2004; received in revised form 6 August 2004 Abstract A finite element simulation of a blister test of an elastic–plastic film, bonded to a substrate and subject to plane strain conditions, is performed. A traction-separation law models the fracture process ahead of the crack tip at the interface between the thin film and the substrate. Only two parameters are significant in describing the traction-separation law: adhesion energy, Γ 0 and interface strength, ˆ σ. The dependences of the pressure, P, and the product of the pressure with the central deflection, PH, on the adhesion properties (Γ 0 and ˆ σ), the geometry and material properties of the film are studied. The latter quantity (PH) has the same unit as the adhesion energy, Γ 0 , and is “conceptually” appropriate for the analysis. We suggest a method to extract the adhesion energy, Γ 0 and the interface strength, ˆ σ, independently from the total energy dissipated. © 2004 Elsevier B.V. All rights reserved. Keywords: Interface; Thin films; Blister test; Traction-separation law 1. Introduction With the increasing application of multi-layered structures of dissimilar materials, the reliability and fail-safe design of the structure is of great concern. For example, electronic packaging and microelectromechanical system (MEMS) fre- quently undergo interface delamination that leads eventually to rupture and failure of the electronic device. Therefore, un- derstanding of interface mechanics in terms of characterizing the interface properties is important. Although many experimental tests were developed in the past [1–4], the pressurized blister test is still a common tech- nique widely used to study the adhesion between dissimilar materials. This test consists of applying a pressure through a hole in a substrate to a thin film bonded to it causing a delam- ination, as shown in Fig. 1. In this paper, a two-dimensional plane strain blister is considered. Although several analyti- cal studies have been made [1–3,5,6], they were restricted to ∗ Corresponding author. Tel.: +65 6874 7168; fax: +65 6774 4657. E-mail address: hb-kais@imre.a-star.edu.sg (K. Hbaieb). interfaces between elastic materials. However, in many ap- plications an elastic–plastic thin film is bonded to an elastic substrate. A finite element analysis is rather appropriate in this case. In this computational study, we employ a cohesive zone model to characterize the properties of an interface between elastic–plastic film and a rigid substrate under plane strain condition. We follow the concept of Needleman [7] who sug- gested a traction-separation boundary condition to specify the fracture process along a plane of crack growth. Tversgaard and Hutchinson [8] further developed this model to study crack growth in an elastic–plastic solid and ductile adhesive joints. In this model, the fracture mechanics is used indirectly and decohesion is described through a traction–displacement relationship. The area under the traction–displacement curve is the adhesion energy, Γ 0 . Since the dominant fracture pro- cess can be measured in microns rather than nanometers, the traction-separation relationship can be regarded as a phe- nomenological characterization of the zone of separation along the interface rather than atomic debonding. This model describes the fracture process through a pair of parameters: 0921-5093/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.msea.2004.08.011