Development of a Simple Numerical Method of the Exhaust System to Find Optimized Design Values 1999-01-1666

During numerical analysis of an exhaust system, the use of shell elements gives accurate results. However, it requires a lot of modeling and calculation time and a big computer system. In this paper, bar elements have been utilized for the numerical analysis of the exhaust system. It shows that the adoption of bar elements providing appropriate results can reduce modeling efforts and computing costs since less than 200 bar elements are enough during the numerical analysis of the exhaust system. To find the equivalent bar properties of curved pipe, the strain energy concept is utilized. The bellows of the exhaust system is simplified with modification of stiffness of bar elements. The developed model can be utilized to find possible hanger position with the analysis of vibration mode. The prediction of endurance performance is another benefit of the developed numerical model with bar elements. Considering endurance performance as well as low vibration level of the exhaust system, optimized design variables such as hanger position, bellows length and location of silencers can be calculated without many efforts or long period of calculation time.