Study On Fatigue Life Of Wheel Assembly Under Multi-axis Random Load With Heavy Duty Vehicle

As a crucial part of the vehicle dynamic system,the strength and reliability of the wheels have a severe impact on the safety of the vehicle.As the only bridge of vehicle’s contact with ground,the stress of the wheels during the driving of the car is extremely complicated,and the research on the fatigue durability of the wheels still faces great challenges.This paper applies the multi-axis fatigue theory to the wheel fatigue analysis,aiming to improve the multi-axis fatigue life prediction method and improve the prediction accuracy of the wheel fatigue life under dynamic random load effects.Taking the front wheel of a heavy commercial vehicle as the research object,this paper proposes a dynamic stress-strain load spectrum acquisition method based on the combination of road load spectrum testing and finite element simulation analysis.The test field collects the six-component load spectrum of the wheel.After the load preprocessing is completed,it is edited based on the pseudo-damage retention method to obtain the input load for reliability analysis.The effectiveness of the input load is evaluated by different load spectrum quality evaluation indicators.Based on the ANSYS software platform,the finite element model of the wheel considering the pre tightening force of the bolt is established,and the pre-stressed modal analysis is carried out.Combined with the modal results of each stage,the dynamic stress-strain response of the wheel at any position can be obtained quickly by using the quasi-static method and multi variable fitting method,and the accuracy of the method is verified by using the complete transient dynamic analysis.Based on the obtained stress-strain load spectrum,the uniaxial fatigue life of the wheels in different sections of the test site was calculated.A new fatigue life prediction method of multiaxial random load is also proposed in this paper.Based on the WB multiaxial fatigue life prediction model,the concept of pseudo damage is introduced to determine the critical plane quickly and effectively.The cyclic information on the critical plane is extracted by the multiaxial rain flow counting.Combined with the linear cumulative damage theory,the fatigue life of the structure under the multiaxial random load is predicted.The results show that the fatigue life prediction results are basically consistent with the test results,which are distributed in the error band of twice the test results.Through the biaxial analysis of the stress state of wheels in different road sections,it is found that the strengthened road section is in the state of multi axis non proportion,and the high ring road section is in the state of multi axis proportion.For different road sections,different multiaxial fatigue life prediction methods are used to analyze the fatigue life,and the predicted results are in line with the actual situation.Finally,based on the principle of damage equivalence,the prediction of load spectrum compilation is given out.