VIBRATION TESTING AND ANALYSIS OF THE PICKUP HEADER OF STRAW FORAGE HARVESTER UNDER MULTI-SOURCE EXCITATION

Abstract

The complex vibration field in agricultural equipment during field operations not only predisposes key mechanical components to fatigue failure, but also leads to crop losses. This study introduces the Operating Transfer Path Analysis (OTPA) method to identify the vibration sources in the pickup header of a straw forage harvester. Finite element modal analysis, vibration testing, and operating transfer path analysis were conducted on the header frame. The findings indicate that excitation sources, including the hammer claw device, transmission, and dust box on the pickup header, are prone to resonant coupling with the header frame. The analysis reveals that the right transmission output shaft contributes 18.3% to the vertical vibrations on the right side panel of the frame. Meanwhile, the left transmission output shaft accounts for 29.4% of the horizontal vibrations on the left side panel. Additionally, the transmission input end is responsible for 54.8% of the horizontal vibrations on the front beam, while the dust box end contributes 45% to the forward vibrations on the rear beam. By identifying the primary transmission paths, the most effective strategies for the vibration reduction and optimization design of the pickup header can be developed. Furthermore, this study offers a theoretical foundation and experimental references for the vibration reduction optimization of other agricultural machinery.