Abstract: To analysis the generality of C-T curve of pre-corrosion factor(C) versus corrosion time(T), the method of comparing C value or comparing parameters of C-T curves is proposed, and the weak- correlation of C-T curve with fatigue load spectrum, stress level and crack size are gained from the testing result. C is the ratio of pre-corrosion fatigue life to un-corrosion fatigue life, and C-T curve is the basis of evaluating the fatigue life for aircraft structure in corrosive environment. To decrease the task for testing the C-T curve, two methods are used to analysis the correlation of C-T curve and the factors, such as fatigue load spectrum, stress level and crack size, and the generality is proved by the pre-corroded fatigue life of the same specimen under similar spectra, constant-stress levels, and different crack sizes. The fatigue test is performed under the spectrum and comstant amplitude loading, and the same conclusion is obtained, so the generality is gained.

Key words: corrosion, pre-corrosion, fatigue life, aircraft structure, fatigue test, C-T curve, generality