Research On Fatigue Simulation Of A Light Cabinet Based On Virtual Iteration

Nowadays, car companies and car users pay more attention to fatigue failure. Since fatigue failure is one of the main failure modes of automobile parts and one of the most important quality indicators for a car. Aiming at one truck cab, the paper puts forward the method of obtaining loading spectrum which is based on virtual iteration method(VIM), conducts the structural and spot fatigue simulation analysis on the cab and assesses the results of simulation based on the results of the real durability test.Firstly, the finite element model(FEM) of cab was built, in which the welding spots were simulated by Cweld units. Cab’s stress distribution and spots’ force and torque were obtained based on inertia relief method.Secondly, a rigid and flexible cab-frame model was established, in which the frame was made flexible by importing a modal neutral file(MNF) in ADAMS. Meanwhile, the original signal of acceleration obtained from proving ground was processed. On this basis, the load spectrum was obtained through virtual iteration, which was based on the rigid and flexible cab-frame model and the processed road signals.Thirdly, the cab’s structure and spot weld fatigue simulation analysis was conducted with the FEM, load spectrum and fatigue properties of material as inputs. The result of simulation indicated that components and spots which are most likely to crack during using were around the mounting holes of the middle and rear suspensions as well as the corners of the B-pillars and C-pillars. Finally, combined with the result of real vehicle test, the result of simulation was assessed. Study shows that the weak positions obtained through the cab’s structure and spot fatigue simulation are basically consistent with the results of real vehicle test, which verified the rationality and feasibility of this method, providing a theoretical basis for further study on fatigue analysis and structural improvements.