Research On Composite Material Honeycomb Structure Impact Localization Applied With Optical Sensing Technology

Composite material honeycomb structure is a special kind of composite structure.It consists of two layers and honeycomb core.Composite material honeycomb structure in the process of using and maintenance are prone to injuries caused by low speed/high speed impact.Damage caused by impact is difficult to detect and great harm.Impact problem of composite honeycomb panel is related to the normal use and maintenance of aerospace structure,so there is a need for monitoring of related research.In this paper,optical fiber sensing technology is used in the composite material honeycomb structure and application research on the impact of the location.The concrete research content is as follows:First,in view of the fiber Bragg grating sensors using only a single wavelength modulation quantity is not enough,we design a fiber Bragg grating tunable linear chirp method based on nickel titanium alloy rod.The relation between strain and displacement of compressive bar has been calculated by material mechanics and simulated by the finite element analysis.Combining the Runge-Kutta method and transfer matrix method,the simulation for chirp grating reflection spectrum has been established.The relation between compressive bar displacement and chirp grating bandwidth and center wavelength displacement is obtained by experimental research.The experimental results show that the chirp fiber grating sensors have a certain application prospect.Secondly,the finite element analysis software ABAQUS has been used to set up a finite element model of composite material honeycomb structure with assembly holes for modal analysis.According to the model,modal resonant frequency has been calculated respectively from one to four class.And steel hemisphere model is established to calculate the impact condition of the upper and lower layers,honeycomb core under three different kinds of working condition in stress analysis respectively.The analysis builds the foundation for the impact experiment and algorithm research.Then,the impact monitoring experiment system based on of the optical fiber Bragg grating sensor for the carbon fiber reinforced composite material aluminum honeycomb sandwich panel with assembly holes has been designed and established.10 fiber Bragg grating sensors are used to record pendulum impact response under different angles.The impact response signal obtained has been preliminary analyzed in both time domain and frequency domain.The assembly hole as damage of honeycomb panel can be recognized according to the impact signal.Finally,the impact location algorithm based on sparse representation is designed.Impact time domain signal is used to establish an over complete dictionary.Measurement vector has been designed.Through orthogonal matching pursuit algorithm and centroid algorithm,impact location can be inferred with good accuracy.The experimental results proved that the impact location method has certain engineering application.