Browse Publications Technical Papers 2009-01-1179
2009-04-20

Development of an Engineering Analysis Tool for Time-Temperature Analysis of Automotive Components 2009-01-1179

This paper describes the development of an engineering analysis tool that assesses the life of vehicle components, after exposure to heat.
As a standard engineering practice, each component or part of a component has a “long term” and a “short term” temperature goal based on the part’s material physical properties. At higher temperatures, component’s physical properties degrade at a faster rate, and the component’s useful life can be significantly reduced. The extent of degradation depends upon the duration of exposure, the magnitude of the over-temperature and rate of thermal degradation.
This tool utilizes actual vehicle test data from test cells or road testing, material physical properties, and expected vehicle duty cycle to determine the expected component life. When component temperature goals are exceeded, the software calculates the total duration of time above the goal temperature.
Kinetic degradation models [12] (which utilize the material’s activation energy value and Arhenius’ kinetic model) are used to calculate the component’s Equivalent Exposure Time (EET) using equation (1) at each temperature over-goal. The model then utilizes the component’s thermal duty cycle (based on the vehicle’s operating duty cycle) and the calculated (EET) values to calculate the component’s total thermal exposure during the vehicle’s lifetime (150,000 miles). The tool then uses these results for a final (Pass or Fail) assessment of the component.

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