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A variety of parameters influence the durability of a converter to pipe joint of an automotive exhaust system. Some of the parameters are design variables and some factors are related to manufacturing. The design parameters include the thickness of the components, diameter of the pipe, sleeve length of the cone etc. While the variables like the weld penetration and the fit-up of the joint are related to manufacturing. Traditional durability simulations utilizing computer aided engineering (CAE) methods are conducted using nominal values of the design and manufacturing variables. In reality scatter and randomness in parameters are present due to the tolerance in components and limitations of the manufacturing process. In this paper a CAE based stochastic approach to determine the life distribution for a converter joint of an automotive exhaust system is presented.

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.