Computational Simulation to Ascertain Hot Vibration Test Assembly for Converter Validation 2015-26-0214

Automotive exhaust system components are exposed to many types of vibrations, from simple sinusoidal to maximum random excitations. Computer-Aided engineering (CAE) plays an inevitable role in design and validation of hot vibration shaker assembly.

Key Life Test (KLT), an accelerated hot vibration durability test, is established to demonstrate the robustness of a catalytic converter. The conditions are chosen such a way that the parts which passes key life test will always pass in the field, whereas the parts which fail in the key life test need not necessarily fail in the field. The hot end system and the test assembly should survive in these aggressive targeted conditions. The test fixture should be much more robust than the components that it should not fail even if the components fail.

This paper reveals the computational methodology adopted to address the design, development and validation of the test assembly. The breakdown issue of the system due to oxidation, creep, plasticity, and mechanical load factors are discussed. Thermal expansion aggregated over the mechanical loading for different configurations helps in detecting the failure mechanism. A correlation factor of less than 5% error has been achieved. The correlation results and the suggested design modification with proper material selection which has been implemented with appropriate bellow selection along with its displacements and stresses are explained. Non-linear material properties are considered in analysis to achieve better accuracy towards reality conditions.