Research On Damage Identification Of Aircraft Structure Based On Fiber Bragg Grating

The composite material has the advantages of light weight,high strength and modulus,and it has become mandatory advanced aircraft structure at present.The use of composite material can not only reduce the weight of aircraft body,and improve the carrying capacity of aircraft,but also improve the design,fatigue resistance and corrosion resistance of aircraft.Therefore,the application location and the application amount of the composite in the aircraft can be used to evaluate the advanced structure of the aircraft.Due to the bad aircraft service environment,any slight structure damage may affect the flight safety.Therefore,it is very important to identify aircraft structure damage accurately and efficiently by studying aircraft structure damage identification which is very important for ensuring the safety of aircraft flight.In this paper,the aircraft composite laminate(model BA9912-G0827)is used as specific research object.First,the structural characteristics,damage factors and damage formation mechanism of the aircraft composite are studied,and the damage identification scheme of aircraft structure is designed.Second,impact and fatigue loading tests are carried out,and the information of aircraft composite laminate under different damage conditions is collected by fiber bragg grating sensors.Then,the variational mode decomposition is used to decompose the original data adaptively,and the singular entropy feature information is extracted.In order to characterize the damage state of aircraft composite structure more efficiently,the kernel independent component analysis is used to fuse the singular entropy feature information of multiple sensors.The obtained fusion feature information is used as the final characterization of the damage state of the aircraft structure.At last,three damage identification models of GRNN,ELM and GRNN-ELM combined neural network are designed,and the accuracy of each damage identification model is verified by the actual test data.The results show that the three damage identification models can achieve the effectiveness of aircraft structural damage identification,and the accuracy of damage identification is 80%,85%,and 90% respectively.Among them,the damage identification model based on GRNN-ELM has the highest accuracy and has a good prospect of engineering application.