Identification Of The Cohesion Zone Model Parameters Based On Digital Image Correlation Technique

Compared with the traditional connection technology,adhesive bonding not only have the advantages on getting smooth surface of the structure,achieving a uniform stress transfer,but also can be used for the connection between the same or different materials.Therefore,adhesive bonding have been widely used in many fields,such as aerospace,mechanical engineering,automobile industry,electrical and electronic industry and so on.But the subsequent degumming,interfacial cracking and delamination damage becomes one of the main damage types for material including interface,this makes the interface performance plays an important role in the overall performance of the material.Therefore,it is particularly important to the interface mechanics performance of the adhesive structure in the engineering application.In the aspect of theory,many theoretical models has been put forward to used to describe the interface mechanical properties,including cohesive zone model,which has been widely applied in all kinds of adhesive interface crack,cracking and toughness composites interface delaminating and so on.Cohesion model parameter acquisition is the precondition of its successful application in various fields.Therefore,how to obtain the bonding interface parameter is problem,which is worthy to in-depth discussion.According to the above problem,based on the bonding structure related experimental results,combined with the finite element model which contains interfacial damage,inversion identification methods were introduced to study the adhesive interface mechanical properties.In this paper,the main work includes the following aspects:(1)Design the aluminum alloy 6061-6T cementing uniaxial tensile test of the double cantilever beam,and obtain the load-displacement curve.The measured displacements and strain field were attained by the digital image correlation(DIC)method from a double cantilever beam(DCB)under mode I tensile loading.(2)Based on the basic theory of cohesive zone model,the corresponding simulated results of damage and failure of interface were obtained by using a cohesive zone model(CZM),which was implemented through the user subroutine UEL in ABAQUS.(3)An inverse analysis was conducted to determine cohesive parameters of flexible adhesive joints based on the Nelder-Mead(N-M)algorithm and the response surface method,in which an optimization model was developed by using the measured local displacement information around crack tip and the corresponding simulated results.The measured displacements were attained by the digital image correlation(DIC)method from a double cantilever beam(DCB)under mode I tensile loading,and the simulated results were obtained by using a cohesive zone model(CZM)which was implemented through the user subroutine UEL in ABAQUS.The predicted load-displacement response curves based on the CZM and the model parameters from inverse analysis are compared with the experimental results to verify the result of parameters properly or not.