A DOE Based Study to Evaluate the Dynamic Performance of an Automotive Exhaust System

Virtual validation of the dynamic performance of exhaust systems with measured vehicle loads is being used increasingly by many OEM's and exhaust system suppliers. The loads induced due to power train roll motion, the vibration characteristic from the ground and power train system are collected during the RLDA (Road Load Data Acquisition). Modal transient dynamic analysis is carried out using FEA with input loading from the full event RLDA to predict the behavior of the system. The key performance measures that are studied in this work are the force transmitted by the exhaust system to the vehicle body and the damage at the critical joints. There are many design variables that could impact the dynamic response of the system like the choice of the isolator, the thickness of the parts, the weld characteristics of joints etc. Inherent variability in the vibration data obtained during RLDA could also influence the behavior of the exhaust system. All the above parameters are analyzed using a DOE (Design of Experiments) based study to identify the levers that could be used to optimize the design of an exhaust system. Also, different approaches to improve the dynamic performance of the exhaust system are discussed and presented in this work. The advantage of this approach is that it can be applied in upfront design and with the availability of virtual RLDA; comprehensive digital validation of the exhaust system is a distinct possibility.