Research On Damage Identification Based On FBG Monitoring Data And PCA Method

For large structures,health monitoring systems are the most important part of the structural safety assurance system,and the most important and core part of health monitoring is structural damage identification and location.Damage identification is the basis of structural health monitoring,and all follow-up activities of health monitoring begin with this.The fiber Bragg grating sensor has low price,good stability and strong anti-interference ability.It is a new type of sensor.Principal component analysis can reduce the dimension of data and better find the difference.In order to further study these two methods,the main work includes:1)A review of the current development of structural health monitoring,illustrating the need for health monitoring of civil engineering structures;The working principle of the fiber Bragg grating sensor and its superiority in modern large-scale structures are introduced.The basic working principle of principal component analysis is introduced.The way of data expansion and organization is determined.The T2 statistic and Q statistic are established as damage indicators,and the types of damage are classified.2)Install fiber Bragg grating sensor and acceleration sensor on the surface of small-scale steel beam model,and collect two kinds of dynamic response data under different working conditions.A fiber Bragg grating sensor is installed inside the large-scale T-beam model,and an acceleration sensor is mounted on the surface to collect structural dynamic response data under different working conditions.3)By using the T2 statistic and Q statistic control graph of Principal Component Analysis,the indicators for judging the damage condition are analyzed to identify the damage state of the structure,and the damage position of the structure is made by using the control variable method.Qualitative analysis.At the same time,the advantages and disadvantages of the traditional sensor and the fiber Bragg grating sensor are also analyzed,and the advantages of the fiber sensor relative to other sensors are obvious.The damage identification combined with the fiber Bragg grating sensor monitoring data and principal component analysis method proposed in this paper is applicable to the beam structure with simple structure,which provides a certain basic research for the future monitoring of complex structure health and has certain practical significance.