Based On The Strain Modal Research Of Piezoelectric Smart Laminated Structural Damage Identification

Composite laminated plate is easily cause to damage in the process of use,which will lead to a decline in the comprehensive performance of its material and cause great damage to the important structure. In order to solve this problem, in this paper, Based on the background of aerospace and used piezoelectric intelligent system to identify the damage of composite laminated structure and evaluation analysis. The main research contents are as follows:(1) By contrast the advantages and disadvantages of the damage identification method of strain modal and structural natural frequencies, found that based on structural natural frequencies can detect damage, but can’t determine the location of the damage. based on strain modal can be very good for damage location and quantitative analysis.(2) Simulation and analysis the damage identification of composite laminated plate. It mainly includes the damage identification, damage location, damage quantitatively the three steps of composite laminated plate damage identification. At first, it based on the natural frequency, displacement mode and strain mode on the three aspects of composite laminated plate damage analysis, found that the strain modal identification effect is the most sensitive to the damage. Then based on the change rate of strain modal, strain modal and the strain modal difference this tripartite face of composite laminated plate is used to identify the damage analysis, found that these kinds of methods for single point of damage identification have very good effect. But only the change rate of strain modal can be good at a multipoint damage positioning and quantitative analysis.(3) Identification a single point damage of composite laminated plate by test. First, set up the test platform according to the theoretical analysis. Then, through the sampling point gather the piezoelectric signal and by filtering noise reduction and the Fourier transform of signal processing, getting the amplitude frequency signal and finding out the composite laminated plate each order natural frequency and amplitude. Then according to the data drawing strain modal vibration mode diagram using three difference spline curve method, by comparing the damage and spoil the vibration mode of the structure diagram can be found about location of damage occur. By increasing piezoelectric strain gauge, to determine the damage location. At the same time using this method for quantitative analysis of the damage.