Research On Formation Mechanism And Inhibition Method Of Pore In Composites Repair Curing

Civil aviation composite structure repair inevitably exist pore in the process of curing, pore will greatly affect the material mechanics performance. So the research of formation mechanism and effective suppression method of the pore appears in the process of composite curing, has important guiding significance in the maintenance engineering practice of composite material structure. In this paper, based on the classical nucleation theory, forecast the effect of different curing parameters to the pore growth under the conditions of composite material maintenance, and test the result of forecast.Using Kardos pore nuclear growth model to calculation and analysis the influence of curing temperature, heating rate, heat preservation time to the porosity in the composite material. Results show that the porosity of the composite increased with the curing temperature and heat preservation time increased gradually, and with the increase of heating rate gradually reduced. Pore nuclear growth rate with the increase of curing temperature and curing time increases gradually.Comparative analysis of several kinds of composite micrograph porosity measurement method. Results show that the method of Photoshop is the most accord with GB/T3365-1982 standard, and has the highest accuracy; the method of Matlab is the fastest method in measuring porosity, the Image tool method is the most pithy method in measuring pore microstructure.Adopt the method of microscopic photography to statistic pore morphology and porosity of the composite sample preparation of different curing temperature, heating rate and heat preservation time, compared and analyzed with theoretical calculation results. Results show that the porosity of the composite increased with the curing temperature increased gradually, and the porosity of the composite is gradually increasing with the extension of heat preservation time, and the porosity of the composite reduced gradually with the increase of heating rate, these are consistent with the results of calculation; Composite pore size, length, width, aspect ratio and the probability of occurrence of big pore gradually increased with the increase of curing temperature, holding time and the decrease of heating rate. The specific data of Porosity calculation results and the testing results of the experiments are different, but the trend is consistent.