Study On Acoustic Emission Characteristics Of Delamination Damage In Carbon Fiber Laminates

Carbon fiber reinforced polymer(CFRP)is widely used in military and civil fields due to its high specific strength,high specific modulus,good performance and eas y forming,such as in space,rockets,aircraft,missiles,wind blades and other manufacturing,as structural materials,functional materials or structural and functional integration of materials,and it is gradually changing from simple parts and secondary bearing parts to large complex structures and main load-bearing structures.The poor shear resistance is the main disadvantage of composite materials,especially the laminated structure.Therefore,nondestructive testing of damage modes of composite materials under shear stress is particularly important.The interlaminar properties of the composites depend on the properties of the matrix,and the properties of the interlayer materials are only a few of the fibers,delamination damage is the most important failure mode of the composites.Therefore,the delamination damage process of carbon fiber reinforced composites is studied in this paper.In this paper,an in-plane damage model of carbon fiber reinforced composite laminates was established to simulate the damage and failure modes of the composites under in-plane shear stress.By using the subroutine function of ABAQUS,the lateral initial damage criterion of composite materials had been two developed,in fiber orientation,the fiber dominated damagewas governed by the Hashin criterion,The matrix oriented damage was governed by the Puck action surface criterion.The[0°/90°]14?[45°/-45°]14 two layers of T700 carbon fiber composite laminates in plane shear was analyzed by finite element analysis,research a nd analysis of the shear process of the damage form and the damage evolution process.Experimental study on acoustic emission monitoring of shear damage of two ply T700 carbon fiber reinforced composite laminates with [0°/90°]14?[45°/-45°]14 is conducted,The strain process of the specimen in the test process was measured by grating optical fiber technology,The acoustic emission characteristics in the process of damage were studied,and the relation between damage form and AE signal was established,the analysis of the load,strain curve and damage morphology was compared with the finite element simulation results,and the simulation results and test results could be verified each other.K-means clustering method was used to cluster the acoustic emission si gnals of the carbon fiber composites during in plane shear process,The selection,counting and duration were taken as characteristic parameters,and the pattern recognition of acoustic emission signals in the shearing process of T700 carbon fiber composites was analyzed,it provided experimental basis for monitoring and predicting the damage of carbon fiber composite materials by acoustic emission monitoring.