Load Spectrum Extraction of Double-Wishbone Independent Suspension Bracket Based on Virtual Iteration

The displacement of the shaft head fails to be accurately measured while the three-axle heavy-duty truck is driving on the reinforced pavement. In order to obtain accurate fatigue load spectrum of the suspension bracket, the acceleration signals of the shaft heads of the suspension obtained by the reinforced pavement test measurement are virtually iterated as responses. A more accurate model of the rigid-flexible coupled multi-body dynamics (MBD) of the whole vehicle is established by introducing a flexible frame based on the comprehensive modal theory. Furthermore, the vertical displacements of the shaft heads are obtained by the reverse solution of the virtual iterative method with well-pleasing precision.

The accuracy of the virtual iteration is verified by comparing the simulation results with the vertical acceleration of the shaft head under the reinforced pavement in the time domain and damage domain. The results show that the rms between the simulated signal and the measured signal is less than 20%, and the relative damage value is in the range of 0.5-2. It can be demonstrated that the rigid-flexible coupled MBD model of the vehicle can obtain relatively accurate iterative results. Compared to durability test results, fatigue simulation analysis using virtual iteration results can accurately predict the location of the damage. It is further verified that virtual iterations can accurately extract the load spectrum for fatigue analysis. Compared with the traditional fatigue load extraction method, the virtual iterative technique can more quickly obtain accurate loads that fails to be directly measured.