An Experimental and Numerical Study of Geometrical parameters Effects on the Strength of Adhesively bonded aluminum Double-cantilever Beam Specimens Using Modified-PPR CZM

The main objective of this study is the feasibility of using Modified Park-Paulino-Roesler (M-PPR) cohesive zone model to simulate The damage in adhesive layer of the double cantilever beam specimen with metal adherents. Considering VIS method for capturing the crack initiation, fracture energy of Araldite® AV138 adhesive with bond-line thickness equal 0.2 mm has been identified based on the linear elastic fracture mechanics (i.e. classic beam theory (CBT), corrected beam method (CBM) and compliance based beam method (CBBM)) and J-integral method (Pradeep method). Following, the bi-linear traction-separation law is first utilized to numerically simulate damage in adhesive layer. The force-displacement curve results obtained through experiments would further be compared with the simulated model and thus bi-linear parameters for this specific adhesive thickness would be inversely obtained. The M-PPR cohesive parameters can be determined by satisfying the boundary conditions along with bi-linear extracted cohesive parameters. First, it is concluded that CBBM is the best method to obtain adhesive fracture toughness in mode I. Using the obtained cohesive parameters and calibration of both models, M-PPR cohesive model in addition to use in metal adhesive joints, presented comparative advantage relative to bi-linear model to simulate adhesive joints under peeling. Meanwhile, effects of the geometrical parameters such as the initial length of the crack and the thickness of substrates on the ultimate strength and stiffness of the adhesively bonded joint have been evaluated.