Research On Health Monitoring Technology Of Flexible Inflatable Structure Based On Optical Fiber Sensor

In recent years,new flexible inflatable structures have been used more and more in the aerospace field,such as large antenna,high-power solar panels,flexible airbags,large space accommodation and so on.Intelligent identification of service status of such structures is of great significance to the design of new aerospace structures and the research of deep space exploration in orbit.For this reason,aiming at the demand of flexible inflatable structure health monitoring,this paper proposes a structure health monitoring technology based on optical fiber sensor,which can realize real-time monitoring of impact,damage and deformation of typical flexible inflatable structure,and improve the safety and reliability of the structure during service.The main contents of this paper include the following aspects:Firstly,a strain monitoring method based on FBG(Fiber Bragg grating)sensor is proposed for 210 D double-sided coated Oxford cloth and aramid fiber cloth.The integration mode of FBG sensor and flexible material is studied,and compared with strain monitoring method based on resistance strain gauge.The advantages of strain monitoring method based on FBG sensor are analyzed,which provides technical basis for subsequent research.Secondly,the static strain response characteristics of flexible inflatable structure FBG sensor under different internal pressure were studied through static loading and impact loading experiments.The impact response signals of FBG sensor were analyzed to provide theoretical basis for the impact load location method of flexible inflatable structure.Thirdly,two shock load locating methods are studied to meet the requirement of impact load monitoring of 210 D double-sided coated Oxford fabric four-sided fixed skin inflatable structure.The first method is based on FBG sensor network system,and chooses the amplitude energy of shock response signal as the characteristic quantity.A shock location method based on boundary mathematical function model and inverse function solution is proposed.The second method uses Sagnac interferometric sensor system to study the impact load location method based on time difference.Then,according to the structural characteristics of the bearing layer of large space inflatable structure and the strain mutation principle of the local damage part under load,a damage monitoring method based on optical fiber sensor is proposed,which realizes the location of the damage area and the identification of the damage length.Finally,taking the flexible cushion airbag as the research object,through ANSYS finite element simulation analysis,the air pressure monitoring method of the cushion airbag is studied,and the corresponding relationship between the internal pressure of the airbag and the surface strain of the airbag is established.Secondly,By obtaining the internal pressure of the cushion airbag and obtaining the deformation information of discrete points in the key area of the surface of the airbag,a deformation reconstruction method based on cubic B-spline interpolation is proposed.