Dynamics sensitivity study of stock car shifter components.

摘要

Previous experience in race situations has shown that components in the shifter section of the stock car drivetrain are subject to failure. As the engine operates in a specific rotational speed band throughout a race event due to gearing rules, the drivetrain components may experience vibrations imposed by that frequency band. It was desired to determine the influence of exchanging components -- namely the setback brackets and shifter handle -- within the shifter assembly. In preparation for potential design changes, an experimental study was performed using a simplified setup. The outcome of this study is the topic of this thesis.;In the simplified setup, only the setback brackets, shifter tower, and shifter handle were included. These were attached to a rigid mass, rather than the stock car drivetrain. Both Finite Element Analysis (FEA) and modal analysis were used to study this simplified model. Modal testing was performed on both the simplified model and the stock car to understand the model limitations. Analysis of these two test set-ups revealed that the simplified model did not fully represent the real system. The natural frequencies of the three modes found in the simplified model matched the stock car measurements to within 17%. However, additional modes were found that were specific only to the car.;Based on these results, it is recommended that the simplified FEA model should be further developed to include all modes obtained from the stock car modal analysis test results. Once a reasonable comparison is achieved, the sensitivity design study may be completed.