Research On Recognition Method Of FRP Composite Material Damage Based On Acoustic Emission Technique

FRP in the airline industry,ship,chemical and electronic parts and even superconducting has been widely applied in engineering for its high specific tenacity,high specific modulus,high tolerance of damage and designable performance.However,during composite materials processing can easily produce composites defects,such as slack?cracks?pores and ill-cohesion of the interface.The factors such as loading,mechanical damage,fatigue,creep and other complex conditions which composites endured in the process of active service may cause the damage of the composite,and the serious damage will lead the entire failure of the material which may cause significant economic losses.Therefore it is important to research on the damage and performance prediction of composites at present.In the process of composite materials bearing,there are many damage forms,At present the analysis method of the FRP composites because the opposite function and the damage of the irreversible process,Often can't monitor the damage process of dynamic and the fault of effective recognition.This paper with FRP composite materials for research object,With acoustic emission as the main research means,studied different weaving method respectively FRP composite sheet damage form,FRP composite material container of water pressure blasting experimental process and Acoustic emission signal characteristics identification,put forward based on the acoustic emission of FRP composite material damage identification of the new method.In this paper application of ABAQUS finite element software FRP composite bearing damage fracture process of finite element simulation,extract crack characteristic parameters of the regional stress field,studiedthe matrix basic theory of the fracture and fiber fracture.By using finite element method to simulating matrix fracture and interface fracture between fiber and matrix,local damage features of composite material were extracted,and strain energy release rate and the corresponding stress intensity factor in different stages of fracture were calculated,and finally,simulation results were coMPared to tensile test results in order to verify the correctness of results.Establish FRP composite veneer tensile and Containers hydrostatic test acoustic emission monitoring experiment system,monitoring FRP composite sheet of tensile fracture and the vessel of water pressure blasting process using acoustic emission.Focuses on the analysis of two typical laid FRP composite materials in different Angle failure form of acoustic emission signal parameter characteristics and waveform characteristics.in the meantime Get the acoustic emission signal amplitude,duration,energy in different stages of the change law of failure through the FRP composite material container of water pressure blasting process acoustic emission signal analysis.And felicity ratio is used to judge the vessel damage degree.The study of acoustic emission characteristics under the damage status of FRP composite material can provide theoretical basis for the performance evaluation of composite materials.finally,The structure is "tight" type wavelet neural network,identify different forms of failure,the introduction of genetic algorithm to optimize network initial parameters optimization so as to avoid network into local optimal solution,then it can improve network convergence and stable performance.The constructed wavelet neural network is applied to the analysis of experimental data,which results show that the network not only satisfy higher error precision requirement but also has good recognition and generalization ability.The research shows that based on the acoustic emission technology damage identification method can provide FRP composite material damage characteristics of different state,And effectively improve the different forms of identification accuracy damage...