13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- old aircraft. 2. The test method and result 2.1. Manufacture of the specimen The material of specimen is 2A12-T4 aluminum alloy with the thickness of 4 mm and the size is shown in Fig.1. The tensile strength bσ is 450 MPa, the yield strength sσ is 325 MPa, the extensibility δ is 15%. 190 18 50 39 15 60 Figure 1. Specimen size The old specimen came from fuselage slab component of some no- corrosive retired aircraft (2A12-T4 aluminum) and was machined as picture 1 according to the loading direction. 2.2. The test method The accelerated environment test was processed in the environment box and the environment spectrum as shown in Fig.2, was used to simulate the natural environment. At present, a mount of tests on the accelerated corrosion in laboratory were aimed at the corrosive fatigue critical component and the effect of environment on the no- corrosive fatigue critical component didn’t be considered [5]. Consequently, on the basis of accelerated environment spectrum of the metallic material and organic material in laboratory, the accelerated corrosive environment spectrum used on engineering at present was modified in this paper and then was applied to the accelerated test of the fatigue critical component. The fatigue critical component would suffer the environment of high temperature and humidity as the corrosive fatigue critical component was suffered, the corrosive factor could weaken as far as possible. The accelerated environment spectrum: ①Temperature:(40±2) ℃； ②Humidity: 90%~95%RH; ③Corrosive liquor: 5%NaCl liquor; ④The time for soak every period: 7.5min, the time for exterior: 22.5min; ⑤Under the glare of the far infrared lamp, keep the surface of specimen dry.
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