Detection of damages in tractor vertical exhaust system by vibration analysis

The exhaust system is used to dispose of the residual products of combustion into the atmosphere and different forces act on it. Excessive vibration caused by various excitation forces resulting from vehicle engine operation and road surface conditions is transferred to the exhaust, causing exhaust systems to be damaged long before their useful life. The vibrations of the exhaust therefore need to be quickly evaluated and clearly analyzed. Some of the exhaust system parameters can be measured, while others can be estimated using comparisons between measurements and finite element analysis (FEA). In this study, a finite element method (FEM) based approach was adopted to solve the vibration problem of the vertical exhaust system of a 90 HP HATTAT/290 brand/model tractor. In the three-dimensional model created using ANSYS WB® software, the natural frequencies and mode shapes of the exhaust system were determined and modal analysis was performed. Improvements were made to the exhaust system in line with the design criteria of the tractor manufacturer and a new design was created. The performance of the new design was evaluated with both numerical simulations and experimental studies conducted on a real exhaust. The results obtained revealed that the rigidity of the system increased thanks to the geometric modifications made and therefore it vibrated at higher frequencies. Thus, a significant decrease was achieved in the vibration levels. The developed new exhaust model was put into production and verified in practice. The study showed that FEM is an effective tool in the vibration analysis of tractor exhaust systems and provides significant contributions to design improvements.