Integrating Road Load Data Acquisition and Signal Processing Techniques to Generate Reliable Drive Files for Electrodynamic Shakers in Testing the Exhaust Systems of Off-Highway Applications

Generating a reliable drive file for an electrodynamic (ED) shaker from Road Load Data Acquisition (RLDA) and validating its correlation with real-world conditions through damage and fatigue analysis is crucial for accurate component testing, particularly in complex systems like off-highway exhaust systems. This paper presents a methodology for creating such a drive file and establishing its validity, highlighting the necessity of ED shakers for simulating the intricate dynamic loads experienced by these systems. The process begins with acquiring comprehensive RLDA under representative operational conditions of the off-highway vehicle. Drive files are generated using this data, which records accelerations at important exhaust system mounting locations. Advanced signal processing techniques are employed to condense the raw RLDA into a format suitable for shaker control. To establish proper correlation, the generated drive file is used to excite the exhaust system on an ED shaker. Acceleration and strain responses at key locations are measured and compared with the original RLDA. Furthermore, fatigue damage calculations, based on material properties and stress-life (S-N) curves, are performed using both the RLDA and the shaker test data. A strong correlation in predicted fatigue life serves as a critical validation metric. The complexity of modern off-highway exhaust systems, characterized by intricate geometries, multiple mounting points, and exposure to severe operating environments, necessitates the use of ED shakers for comprehensive durability testing. Field testing alone can be time-consuming, expensive, and difficult to control. This research demonstrates that a well-correlated ED shaker drive file, derived from RLDA and validated through damage and fatigue analysis, provides a reliable and efficient method for simulating real-world loads with thermal (hot gas) considerations in a controlled laboratory environment. This application-oriented approach offers significant advantages for predicting component life, optimizing designs, and ensuring the long-term reliability of exhaust systems in demanding off-highway applications.