Research On Infrared Detection Technology Of Thick Skin Honeycomb Sandwich Structur

Honeycomb sandwich structure composite material consists of carbon fiber skin,epoxy resin binder and aluminum honeycomb core plate,with high specific stiffness,high specific strength,low density and other characteristics,widely used in the aerospace industry.In the engineering application,it is found that after the honeycomb sandwich panel is cured,the thermal expansion coefficient of the thinner carbon skin honeycomb sandwich structure and the metal embedment is different,which will lead to the carbon skin cracking,and after the carbon skin is thickened to 0.8mm,the honeycomb sandwich structure has no cracking phenomenon.However,at present,the detection of carbon skin honeycomb sandwich structure plate larger than 0.8mm is difficult and cannot effectively obtain excellent detection results.The infrared thermal imaging detection technology is relatively good for the detection of masked honeycomb sandwich structure plate,therefore,the infrared detection technology is studied.Firstly,for the problem of loading uniformity of infrared excitation of honeycomb sandwich structure plate,the theory of infrared detection of honeycomb sandwich structure is established,the heat transfer process of infrared excitation on honeycomb sandwich structure plate is systematically analyzed,and the temperature difference equation between defects and nondefects on honeycomb structure plate is deduced.After that,the simulation and data processing software are used to conduct a comparative study of the pulse fitting derivative method,the phaselocked-amplitude method and the phase-locked-phase method in the infrared detection technique for the planar and curved honeycomb sandwich structure panels,respectively,to verify the infrared detection theory of honeycomb sandwich structure and to determine the experimental research methods for the planar and curved honeycomb sandwich structure panels.Finally,the influencing parameters of the infrared detection technique are analyzed and it is determined that both excitation parameters and sampling parameters affect the infrared detection results.Therefore,an experimental study of infrared inspection process parameters for curved honeycomb sandwich structure panels and flat honeycomb sandwich structure panels was conducted to optimize the process parameters for infrared inspection techniques.The test results show that after the process parameter optimization,the infrared inspection technology can efficiently and in large quantities inspect the thick skin honeycomb sandwich structure,solving the problem that the previous inspection technology cannot effectively inspect the curved panel honeycomb sandwich structure.