Multiaxial Fatigue Life Prediction of Rear Suspension

Abstract:

Considering the elastoplastic deformation of material,a transient dynamic analysis for rear suspension is conducted under the boundary condition of cobblestone strengthen road loads.Crack initiation life of rear suspension is accounted by using traditional uniaxial strain life method.However,biaxial analysis of stress—strain time history indicates that the hazardous areas of rear suspension are subjected to a multiaxial non-proportional loading.Based on multiaxial fatigue theory,the material non-proportional appending hardening mechanism and crack type are considered.The multiaxial fatigue life is predicted by using Bannantine model and Wang-Brown model which are deduced with the critical plane method.Uniaxial fatigue life on the basis of the same material is also predicted for a comparison.It indicates that the life under the non-proportional loading is largely decreased and the result predicted by uniaxial fatigue theory is dangerous.

Key words:twisted beam rear suspension; multiaxial fatigue; critical plane method; multiaxial non-proportional loading; life prediction