Progressive damage analysis on adhesively bonding patch repair of composite laminates

A 3D FEM was presented for the progressive damage analysis on the adhesively bonding patch repair of composite laminates.The constitutive model of laminates and adhesive were established with the orthotropic damage tensor and isotropic damage variable in the frame of continuum damage mechanism,respectively.The failure initiation,progression and their interactons of both laminates and adhesive were take into considerations during the whole analysis.The proposed model was validated by the existing experiments of the bonding patch repair of laminates under compression.The effects of repair parameters on the repair strength were also evaluated with the proposed model.The results show that the patch failure is the critical factor of the repaired laminates strength when the patch is thin,while the adhesive is the critical factor of the repaired laminates strength when the patch is thick enough.Under this condition,the laminates strength will not increase with the increase of the patch thickness.Therefore,the patch and adhesive should be designed carefully and optimized before an adhesively bonding patch repair on a damaged laminates.