Fatigue Life Of The Aluminum Alloy Material Based On X-Ray Scanning

Most of the damage to mechanical parts belongs to fatigue failure. When fatigue failure happens, mechanical parts have a brittle fracture instead of producing significant plastic deformation. Fatigue failure is in an invisible form, which will lead to serious accidents when it happens. The essence of the problem is that there are kinds of defects inside material or structures. The evolution and expansion of defects finally lead to fatigue failure. Then the issues of fatigue defects and fatigue life become the focus topic of this paper.Firstly, on the basis of the equivalence of complementary elastic energy, a multiresolution rule that transforms different levels of material defects to the equivalent degradation of material properties will be introduced. One of the advantages of this rule is that we can simplify the process of establishing complex model, and also avoiding calculation and analysis of the complex process of meshing and calculating. The other advantage is that it facilitates partial damage transformation.Then, a series of numerical simulations about multiresolution rule will be conducted. The damage variable is effective Young’s modulus. Compared with the results of numerical simulation and calculating, it is found that the results are very close, which can verify the feasibility of this rule.Subsequently, a series of fatigue test of constant amplitude cyclic loading will be conducted. The damage variable is also effective Young’s modulus. Compared with the results of fatigue test and calculating, it is found that the results are also very close, which can further validate the accuracy of this rule.Finally, to the aluminum alloy specimens of fatigue test, determine the characteristic length of detects by scanning aluminum alloy specimens which in a cyclic loading phase that you do not know by X-Ray. Then these detects will be divided into different levels. Calculate effective Young’s modulus with multiresolution rule.Comparing the relations of effective Young’s modulus and fatigue life, the used fatigue life and residual fatigue life of these aluminum alloy specimens can be judged.