Research On Damage Identification For Composite Laminates With Piezoelectric Wafer Active Sensors Array

Structural health monitoring technology is one of the leading research directions in the research of materials, mechanics, measurement and control, and information communication. So far, the technology has been studied for nearly 20 years. Because advanced composite materials have high strength and stiffness, they can reduce the quality and improve the performance of the aircraft structure, which are used more and more in the aircraft structure. So the reliability and safety of the composite structure should be considered. In the process of manufacturing and using of composite materials, it is inevitable to be affected by different degree of damage, especially the matrix cracking, internal delamination and fiber fracture damage caused by impact and fatigue. The continuous accumulation of these damage will greatly reduce the safety performance of the aircraft. If we can’t discover the damage in the structure in time, it can result in disastrous consequences. So it is very important to study the damage monitoring of composite materials. The structure health monitoring technology based on Lamb is sensitive to the crack and delamination in the structure. It is considered to be a more effective method for on-line structural damage detection at present, which has become an international research hotspot and has a broad application prospect. In this paper, the damage detection of composite laminates based on piezoelectric wafer sensors is studied, which provides a certain theoretical and practical basis for the application of active structural health technology based on Lamb wave in practical engineering. The main research contents include the following aspects:Firstly, the basic theory of Lamb wave is studied and the propagation characteristics of Lamb wave in the structure are discussed. This paper introduces the principle of the excitation signal generated by the piezoelectric wafer sensor and deduces the relationship between the surface of the piezoelectric wafer sensor and the composite laminate. The equivalent simulation model of the sensor is obtained. The damage modeling methods for composite laminates are introduced.Then, a finite element simulation method of Lamb in composite lamin ates is introduced in detail. The finite element simulation of the propagation of Lamb wave in the composite laminated plates under the condition of damage and damage is carried out respectively by the finite element method. The propagation process of Lamb wave in the structure is obtained and the displacement response signal received by the sensor array is presented Damage identification of composite laminates under different damage conditions are simulated and calculated.Finally, the displacement response signal received by the sensor is processed by data processing. The existence of damage in the structure is judged. And the signal was processed by the Fast Fourier Transform of the typical frequency domain method. The existence of the damage is further verified. The results of the composite laminates under different damage conditions are compared and analyzed.