Study On Structural Health Monitoring Of Ultrasonic Guided Wave Based On Centralized Sensor Array

In the process of industrial production,the metal plate structures are more and more widely used in the components of large structures,such as aircraft,wind blade,ship,rail and so on.Those structures are easily eroded due to their harsh service conditions and inherent structural characteristics.As service time goes by,the fatigue crack generates and develops to macro defect,which bring great security menace to structures.Therefore,timely monitoring of these defects is of great significance.Traditional non-destructive testing(NDT)has slow,time-consuming and high cost.The testing technology of ultrasonic guided wave can quickly detect the defects,which has the characteristics of wide detection range,high detection sensitivity and short detection time,and can be more suitable for the needs of modern nondestructive testing.The testing technology of ultrasonic guided wave based on centralized piezoelectric sensor array was studied in this paper.On the basis of derivating the of ultrasonic guided wave,the dispersion and multimode characteristics of the guided wave in the plate were discussed.The signal processing method and its related principles of ultrasonic guided wave were also analyzed,which laid theoretic foundation for the detection technology of ultrasonic guided wave based on centralized piezoelectric sensor array.The experimental testing platform was built independently and ultrasonic guided wave was excited in plate by stimulating PWAS.The artificial defect was produced and defect characteristics was extracted from original signal.The defect was evaluated by developing damage factor.The PWAS sensor array was constructed,and the defect testing imaging was obtained,which is applied to locate the defect.The finite element method is used to simulate the defect detection of ultrasonic guided wave.The influences of defect size and the distance between defect and the source of guided wave were analyzed.The signals obtained from numerical simulation were also used to form imaging of defect.The numerical results were compared with experimental results.The results show that the structural health monitoring technique of ultrasonic guided wave based on centralized sensor array can effectively detect the damage in plate structure.The defined damage factor can evaluate the damage degree of plate structure.The results of visual image were obtained,which were used to locate defect.The results of experiment and numerical simulation show good agreement.