Failure analysis of composite wing adhesive joints using 3D cohesive interface element

Due to high strength and stiffness in comparison with their weights، laminated composite materials are widely used in many structures such as aerospace. Therefore to predict their mechanical response، the understanding of their failure mechanisms is very important. The delamination between composite layers and adhesive joints is one of the main damage modes of these materials. In this research، the cohesive zone model is used to predict the damage evaluation of composite wing adhesive joints. The advantage of this method is the modeling of delamination growth without any requirements to the presence of initial crack and remeshing. Moreover to predict the probable damage in composite layers the Ladeveze progressive damage model has been implemented in Abaqus using user defined code (Umat) and also the importance of considering the intralaminar failure on the acceleration in damage initiation and propagation in adhesively bonded joints have been evaluated. The results verify the proper accuracy of implemented method. Furthermore، the results of solid cohesive elements showed to be more accurate in predicting damage initiation and evaluation in comparison to shell elements. Finally effects of adhesive properties such as thickness and quality of bonding in load capability of wing structure have been investigated.