Experimental And Numerical Analysis Of Composite Structures With Initial Delamination

The composite material is susceptible to delamination damage under external load,which results in the delamination buckling and the mechanical properties of the composite are seriously affected.Therefore,the mechanical behavior of the composite structure with initial delamintion has very practical engineering significance.In this paper,the effects of different delamination and repair methods on the mechanical properties and buckling behavior of the composite structure are studied in terms of static compression tests and finite element analysis.In this paper,the compressive behavior of composite stiffened plate with delamination and single countersunk bolt composite laminate joints with delamination is studied.The research contents include:(1)Static axial compression test of composite stiffened plates.The axial compressive tests were carried out on composite stiffened plates with or without repair.During the test,the ultimate load and failure mode of different test specimen was recorded.Three types of delamination damage in the test specimen are considered: delamination in the a quarter of the skin,delamination in half of the skin,and debonding between the skin and stiffemers.Repair methods include: mechanical repair,patch repair,repair and repair.The effects of different damage and repair methods on the mechanical properties of the stiffened plates were investigated by the numerical model.(2)Numerical simulation and parametric analysis of composites with initial delamination.Based on the ABAQUS finite element software,the finite element model of the stiffened composite plate and its repair parts with initial delamination were established.The accuracy of the numerical model was verified by the experimental results.The effects of various parameters and repair parameters on the mechanical properties of the composite stiffened plate were studied.(3)Experimental study and finite element analysis of composite bolted joint with hole delamination.The axial static compressive test of the composite bolted joint with hole delamination is carried out and the simulation in ABAQUS was performed at the sametime.The results has reached a good agreement between the FEM and experiment,which proves the validation of the finite element model.According to the numerical results,the progressive damage process of the fastening holes and fasteners in the mechanical link structure was analyzed.The effects of different delamination parameters on the mechanical properties of the mechanical joints were investigated.