Fatigue Life Prediction Of Aluminum-alloy Wheels In Consideration Of Casting Defects

The wheel is an important safety component of the vehicle traveling system and its performance plays a crucial role in the safety and reliability of the complete vehicle.The fatigue performance is an important performance index of the wheel so that GB in China,SAE,and ISO all have made detailed technical requirements about it,among which the bending fatigue test and the radial fatigue test are performance tests that the wheel must pass.Most of the traditional wheel design relies on the experience of designers and has great blindness,resulting in the high cost of research and development and the long design cycle.In order to adapt to the increasingly fierce market competition,most of the wheel companies at home and abroad have already introduced the finite element method to guide the improvement and design process of the wheel.At present,the finite element analysis has been developing more and more mature.However,there is still a certain gap between the predicted results and the actual results.The main reason for this phenomenon is that the input data of material is not accurate enough,and the setting of the boundary condition is different from the truth-condition.The manufacturing process of aluminum alloy hub is a complicated low-pressure casting process.The defects and structural irregularities generated during the casting process will affect the mechanical properties of the material.Therefore,if a uniform material property is set during the finite element analysis process,it will inevitably affect the analysis result.To solve this problem,this paper first simulates the low-pressure casting process of aluminum alloys,predicts their defects and distribution of the structure,and then prepares a material model with secondary dendrite arms as the influencing factor by compiling the Fortran program.Based on the secondary development of ABAQUS,a material model considering casting defects was introduced through the UMAT interface to simulate the bending and radial fatigue test of the wheel,and finally through the FE-SAFE software to analyze and predict the fatigue life of the aluminum alloy wheel.This paper realizes the integration of casting simulation,structural finite element analysis and fatigue life analysis.In order to verify the accuracy of the fatigue life prediction of the integrated casting defect,also analyzed the fatigue life under uniform material properties.By comparing with the real physical experiments,it was found that the fatigue life prediction of the hub considering the casting defect can be more accurate in predicting the location of the occurrence of fatigue cracks and the number of cycles experienced when fatigue cracks occur.