Experiment And Simulation Study On Ductile Fracture Of Aluminum Alloy Under Multiaxial Load Condition

Aluminum alloy has many advantages such as low density,high strength to weight ratio,corrosion resistance,good processing performance,low maintenance cost and easy recycling.It has been widely used in aerospace,transportation,shipbuilding and building bridges,etc.It’s the most widely used non-ferrous metal structural materials in the industry.With the rapid development of the industrial economy,the demand for aluminum alloy structural parts is increasing.5083H116 aluminum alloy is a marine aluminum alloy with excellent performance and is widely used in marine structures.The fracture behavior of aluminum alloy is a typical ductile fracture.In actual engineering,the stress state of aluminum alloy structural members is very complicated.It is necessary to study the ductile fracture mechanism of aluminum alloy under multi-axial load condition in order to accurately predict the fracture failure of aluminum alloy materials..In this paper,5083H116 aluminum alloy sheet is used as the basic research material,and on the basis of the existing research results on the effect of stress state on ductile fracture,a series of circular notch specimens and shear specimens which can produce different stress triaxial T and stress Lord parameter L are designed and processed.The change of strain field near the gap area of the specimen during the experiment was observed by digital image correlation technology.The load displacement curve obtained by experiments shows that different stress states will have a significant effect on the peak load and failure displacement of the specimen.At the same time,the parameters of 5083H116 aluminum alloy in Micromechanics damage model are determined quickly by polycrystalline simulation based on crystal plasticity theory,and the calibrated parameters are applied to the finite element simulation of macroscopic ductile fracture experiment by GTN microscopic damage model.By comparing the simulation results with the experimental data,it is found that the consistency degree is very high,which verifies the accuracy of the parameter calibration,and also validates the results of the microscopic mechanical simulation based on the crystal plasticity.In the aspect of microstructure,through X-ray synchrotron radiation Experiment,the changes of material holes during the ductile fracture of aluminum alloy and the morphological appearance of holes in the polymerization process are observed,and the observation results of the microstructure of the materials are combined with the experimental results of macroscopic ductile faults and the simulation results of GTN microscopic damage model,and the comparative study is carried out.It has a more intuitive understanding of the evolution of holes in the process of ductile fracture,and also provides a reference and basis for further research in the next.To sum up,this paper studies the toughness fracture of aluminum alloy material under multi-axis load under the condition of experiment and simulation,and obtains the relevant results,tests the results of the relevant micromechanics simulation,and makes the prediction of fracture failure of aluminum alloy material under complicated working conditions more accurate and rapid,Make the application of aluminum alloy in practical engineering more safe and economical.