Study Subbing Layer In The Composite Material Damage Detection FBG Sensor And Optimization

At present,high-tech composites for the protection of spacecraft are usually used for bonding process,manufacturing and maintenance process will inevitably lead to defects and damage.Therefore,it is necessary to use accurate and reliable structural health monitoring technology to monitor the quality of composite bonding,which is very important.Fiber Bragg grating sensors have many advantages for health monitoring solve structural problems.It is widely used in the aerospace field.At present,the application of FBG sensor network for composite structure of adhesive layer structure health monitoring is a new method,After embedding the adhesive layer,the FBG sensor's own strain transfer characteristic and the sensitive range need further exploration,The optimal configuration of the sensor network needs to be combined with the structural characteristics of the FBG sensor and the mechanical properties of the structure.Therefore,based on the FBG sensing principle,this paper studies the defects of the composite layer.First of all,this paper studies the quality of adhesive bonding of composite materials used in aerospace thermal protection.The material has the characteristics of porosity,anisotropy,low thermal conductivity and strong sound absorption,This paper presents a new method for the detection of rubber layer defects in the structure of spacecraft body protection material,And this method is based on FBG sensor network monitoring system,This method places the FBG sensor into the composite adhesive layer,forming a distributed sensor network to achieve the purpose of high-precision defect detection.Experimental platform,the adhesive layer of the composite material is embedded FBG sensor experimental study of static load,obtained under external load sensing characteristics of the FBG sensor.Secondly,according to the characteristics of the structure and material,the strain transfer characteristics and the sensitive range of FBG sensor are studied in order to establish the perceptual model of FBG sensor composite layer.FBG sensor strain sensing model is established by combining modeling analysis with experiment.Based on FBG strain perception model,the number and location of sensors are optimized by intelligent optimization algorithm,and the construction method of distributed FBG structural strain monitoring network with high performance and high reliability is studied.Based on the optimal allocation criterion,FBG sensor network is optimized by particle Particle Swarm Optimization,and the algorithm is improved to make the sensor network layout more suitable for FBG sensor structure.Finally,according to the FBG sensor network optimization results to build experimental platform and carry out strain monitoring experiments.A square area monitoring experiment and a defect simulation test were carried out to verify the optimization effect,combined with the finite element simulation results to achieve the effect of defect detection.This study explored the FBG sensor network for the detection of composite material defects.Which will lay the foundation for the research of FBG sensor network for structural damage identification.