Accelerated Corrosion Environment Spectrum for Aircraft Dissimilar Metal Joint Structure Based on Small Sample Parameter Estimation Method

The natural environment spectrum and equivalent conversion relationship are important input parameters for the complication of aircraft acceleration test environment spectrum. Due to the large discrete nature of environmental data and the small number of sample data, traditional parameter estimation methods are no longer suitable for compilation of natural environment spectra. Based on the idea of small sample parameter estimation, this paper established a high confidence natural environment spectrum through Bootstrap data expansion and grey confidence interval estimation. Subsequently, electrochemical tests were carried out on 7050 aluminum alloy and TC18 titanium alloy, which were typical dissimilar metal connection materials for aircraft, and their equivalent conversion coefficients were calculated at the temperature of accelerated test environment based on the principle of isoelectric quantity. On this basis, the accelerated test environment spectrum of aluminum-titanium alloy joint structure was given, w