FATIGUE CRACK GROWTH IN D16T A1-ALLOY SHEET SUBJECTED TO BIAXIAL OUT-OF-PHASE LOADING
| Autor: | A. A. Shaniavski, V. M. Grigoriev, E. F. Orlov |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Materials science
business.industry Mechanical Engineering Fractography Fracture mechanics Structural engineering Paris' law Crack growth resistance curve Mechanics of Materials visual_art Aluminium alloy visual_art.visual_art_medium General Materials Science Growth rate Composite material business Striation Stress intensity factor |
| Zdroj: | Fatigue & Fracture of Engineering Materials & Structures. 20:975-983 |
| ISSN: | 8756-758X |
| Popis: | Fractographic peculiarities of fatigue crack development are studied in cruciform specimens of D16T aluminium alloy under out-of-phase biaxial tension and tension-compression. In the range of the biaxial load ratios λ from -0.5 to +0.5 and an R-ratio of 0.3, fatigue striation formation took place beyond a crack growth rate near to 4 x 10 -8 m/cycle. The striation spacing and the crack growth rate increase as the O-angle of the out-of-phase biaxial loads increases in the range of O-angles from 0° to 180°. The ratio between the increment of crack growth, da/dN, and the striation spacing, δ, is approximately 1 to 1 when da/dN is greater than 4 x 10 -8 m/cycle. The relationship between the number of cycles from the beginning of a test up to the growth rate of 10 -6 m/cycle (N d ), and the crack growth period, N p , from when the crack initiates up to the instant when that growth rate is reached, was determined for different λ ratios and O angles. The value of N d decreases as the O angle is increased in the range from 0° to 180°. Cycle loading parameters must be taken into account in order to describe the crack growth period when using a unified method that involves an equivalent stress intensity factor K c = K I f 1 (λ,R)F 2 (O). The values of F 2 (O) were determined. The calculated fatigue crack growth period, N c , applicable up to and including the stage of fatigue striation formation (predicted by using both of the F 1 (λ,R) and F2(O) functions) is correlated with the experimental data and the error is of the order of 15%. |
| Databáze: | OpenAIRE |
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