Finite Element Simulation Of Fatigue Crack Growth Behaviorof 5E62 Aluminum Alloy

Aircraft skin accounts for more than 50% of the whole machine structure weight, which need to bear complex pneumatic loading and was taken as an important component on the damage tolerance design for modern aircrafts. NIE Z R research group has innovated 5E62 aluminum alloy independently which mainly used in aircraft skin. It has high degree match of strength with damage tolerance. By adopting the combination of experimental and numerical simulation method to predict the fatigue damage process of material, we can save human resources, material and money, that’s why it is a good way to prevent the happening of the fatigue damage in engineering applications.XFEM method was used to calculate the crack tip stress, as well as stress intensity factors KI and fatigue crack propagation rate in fatigue crack propagation for the MT sample of 5E62 aluminum alloy. The macro finite element model of fatigue crack propagation was established by ABAQUS-XFEM method. The crack propagation path expanded along a straight line which is perpendicular to the load direction, and consistent with the experiment result well. XFEM method was used to calculate the fatigue crack propagation rate in Paris area, which had a good consistency with the theoretical and experimental value. Fatigue crack propagation rate kept approximate linear growth and increased with the increasing of the value of ?K. XFEM method was used to calculate the KI value of the half crack length from 4.5 mm to 26.5 mm, which has the maximum error 8.9% when compared with the theoretical value. The interval length of the steady state in was 5.8~24.5mm resulted from the simulation, which had the error of 22.4% and 16.3% respectively with the experimental data.By calling the rate relevant user’s material subroutine of ABAQUS crystal plasticity finite element model was established. The crack tip stress distribution, the crack tip opening displacement and J integral of single/double textures were calculated to explore the influence of the orientation on the crack propagation. The crack tip plastic zone, S22 and CTOD and J integral of Cube and S texture were less than Goss and Brass texture. However, the stress release area of Cube and S texture were bigger than Goss and Brass texture. Mises equivalent yield stress, CTOD and J integral of Cube texture was the minimum. And the Mises equivalent yield stress at the crack tip of S texture is the largest, but the other two directions shared a part of the stress, resulting the S22 play the leading role of the crack propagation relatively low. The plastic zone and J integral of Goss texture was the largest, and the CTOD of Brass texture was the largest. In conclusion, the Cube and S texture has a strong ability of resisting crack extension, while Goss and Brass texture has a low resistance to crack propagation.The crack tip plastic zone, Mises, S22 and CTOD values of Double texture was reduced when compared with single texture. The CTOD, J integral and S22 of Cube-X double texture were at the lowest level, and the CTOD, J integral and S22 of S-X double texture were at the second low level. The crack tip plastic zone, S22 and J integral of Cube-S texture were the smallest, while the crack tip plastic zone,S22, CTOD and J integral of Brass-Goss texture were the largest. In a word, the texture that contains Cube has stronger ability of resisting crack extension; the texture including Brass has the ability of poor resistance to crack propagation. The simulation of fatigue crack propagation behavior for 5E62 aluminum alloy has a certain guiding significance on experiments.