Study On Pyrolysis Mechanism And Combustion Charact Eristics Of Sandwich Structure Aircraft Panel Materials

Fiber reinforced resin-based sandwich structure panel,as an emerging aviation interior material,has begun to gradually replace laminate material and become the main material of aircraft interior panel because of its remarkable advantages of high specific strength,corrosion resistance and high specific modulus.Nowadays,this fiber reinforced resin-based sandwich structure material is used in Airbus aircraft and some aircraft cabin and cargo cabin interior panels in China.Fiber-reinforced resin-based sandwich panels are widely used in the aerospace field.However,the research on the pyrolysis and combustion behavior of fiber-reinforced resin-based sandwich panel materials has not been publicly reported.Therefore,this paper takes the panel material of civil aircraft sandwich structure and its constituent materials-laminated plate material and honeycomb core material as the research object.The pyrolysis mechanism and combustion characteristics were studied.The main conclusions are as follows:1.The initial pyrolysis temperature and final pyrolysis temperature of resin base platen and honeycomb core materials shift to the direction of high heating rate during pyrolysis.When the heating rate increased from 15°C/min to 30°C/min,the apparent activation energy of pyrolysis of laminate material increased from 288.09 k J/mol to 313.73 k J/mol,and the apparent activation energy of honeycomb core material increased from 346.53 k J/mol to 370.14 k J/mol.The initial pyrolysis temperature and final pyrolysis temperature of resin base platen material and honeycomb core material decrease with the increase of oxygen concentration.When the oxygen concentration increased from 10%to 30%,the apparent activation energy of pyrolysis of laminate material decreased from 287.25k J/mol to 275.27 k J/mol,and the apparent activation energy of pyrolysis of honeycomb core material decreased from 360.76 k J/mol to 326.77 k J/mol.By comparing the apparent activation of the material,it is determined that the laminate material in the sandwich panel material is the weak part of the pyrolysis stability.2.During the pyrolysis of the laminate material,CO began to produce at 467°C,peaked at530°C,and no longer released at 600°C.During the pyrolysis process of honeycomb core materials,ammonia gas began to be generated from 384°C,and the yield remained basically unchanged when the temperature reached 460°C.3.At 400°C,the laminate material undergoes a significant pyrolysis reaction,mainly generating phenolic substances.At 600°C,the laminate material no longer releases water vapor and carbon monoxide.Mainly release phenolic substances.At 800°C,the main substance produced by the laminate material is anthracene compounds.The main products after pyrolysis of honeycomb core materials are carbon dioxide and 1,3-phenylenediamine,and the content of1,3-phenylenediamine decreases with increasing temperature.4.When the heat radiation intensity increases from 30 k W/m² to 50 k W/m²,the ignition time required for material combustion is shortened by about 34%.The peak value of the first peak of the heat release rate peak increases from 20.33 k W·m^-2 to 43.52 k W·m^-2,and the peak value of the second peak increases from 3.28 k W·m^-2 to 47.36 k W·m^-2.The total amount of flue gas release increases by about 1 times,and the peak value of O₂ consumption increases by about 4 times.The enhancement of thermal radiation intensity promotes the combustion reaction of the material to the right.The ignition temperature prediction model of sandwich panel material is established.The theoretical critical heat flux of sandwich panel material is11.43 k W/m² and the ignition temperature is 683.78 K.