Frequency Domain Loads Processing for Exhaust Systems

Philippe Leisten; Neil Bishop; Arnulf Spieth

doi:10.4271/2020-01-0180

A previous SAE paper (2018-01-1396), (see ref 5) introduced the concept of using the frequency domain for exhaust system analysis under road excitation as a fast and efficient approach. During the intervening period further benchmarks have confirmed the validity of the approach for several exhaust systems comparing the results of simulations performed in the time domain and frequency domain for different applications.

This paper will present that data and also introduce a new technique which has been developed to create, from the originating road load data (RLD), the cutting plane loads at any desired section of the exhaust system. Those loads can be used directly to determine safety factors against load capacities based, for example, on part SN curves from current or former hardware testing or even derived from statistics.

The advantage lies in the early availability of virtual models in the development process, providing information about the loads acting on the system before any hardware can be built or measured.

Another big benefit relates to the high variability and flexibility of post-processing using CAE tools which stands in opposition to the fixed strain gage positions in measurement which makes sensitivity studies or additional evaluations impossible.

Last but not least, this method can also be applied to provide better information about load targets to be achieved by, for example, supplier parts, like flex pipes or flaps. This can therefore support early application-tailored designs. Or it can be used for the extraction of loads for shaker testing and replace generic loads that may lead to over engineering.

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Frequency Domain Loads Processing for Exhaust Systems 2020-01-0180

SAE MOBILUS