Assessable Method Of Erosion Damage Tolerance On Typical Structure Of Aircraft

A series of serious corrosion questions were researched combines corrosion problem in the major axles of the tail horizontal wing on typical plane in this paper systematically, which include the main reason and mechanism for the corrosion occurrence in the tube inner structure on typical plane, accelerated corrosion test methods, probabilistic distribution and development of corrosion, corrosion influence on fatigue life and the evaluation method of corrosion damage tolerance, etc. And several innovation were made as following.1) For the first time discover there existence silk form corrosion phenomenon inside metal structure under coat. The characteristic of stress corrosion damage and silk form corrosion in metal base near the welding seam was found. In the corrosion surroundings protective coatings is harm, stress corrosion damage is increment along with increment of corrosion time. stress corrosion damage will generate and develop constantly around the welding seam, fatigue crack will generate by the influence of cyclic load on the location where the stress corrosion damage is serious, even result in rupturing. Thereby more ravel the corrosion mechanism of typical tube inner structure on service aircraft.2) The accelerated corrosive environmental spectrum and the accelerated corrosion test methods were put forward for the local environment and characteristic of corroding of tube inner structure on typical plane. The result indicated that the corrosion features the typical aircraft structures appeared during the active service were reappeared well under the condition of the laboratory, and have offered test methods for the studying of corrosion process of tube inner structure and evaluating anticorrosive quality and service life of the coating system. 3) The distribution and development of corrosion damage of the 30CrMnSiNi2A steel were studied by the accelerated corrosion experiment using the cycling soaking accelerated corrosion testing, measure two sets meantime corrosion depth, the probability density function of maximum corrosion depth of the 30CrMnSiNi2A steel accord with according to Gumbel distribution, Normal distribution, Weibull distribution and Log-Normal distribution. The results indicated that the max corrosion depth more close Normal distribution, therefore provide evidence for the corrosion damage of the 30CrMnSiNi2A steel statistic analysis.4) Establish corrosion damage influence correction coefficient, and put forward for the first time acquire dissimilarity corrosion S～N curve by the normal S～N curve with the coefficient. A set of fatigue test was carried on the result enunciation of verification, calculation life span according to the S～N curve is as same as the average experiment life span.5) The corrosion damage tolerance and token method was define, endoscopic picture was put forward to contrast to make sure corrosion damage degree, and built up connection between corrosion damage picture with fatigue life, it provide importance proof for make sure the corrosion damage tolerance, the criterion of repair and the method of repair in tube inner structure on aircraft.