Influence of tyre inflation pressure on whole-body vibrations transmitted to the operator in a cut-to-length timber harvester

Abstract

The influence of tyre inflation pressure on whole-body vibrations transmitted to the operator during the movement of a cut-to-length timber harvester was evaluated. Vibration measurements were taken in three orthogonal ( x, y, z) axes at tyre pressure settings of 138, 345 and 414 kPa. Vibration was predominant in the vertical (z) direction with the peak rms acceleration value for the operator seat (0.281 m s −2) occurring at approximately 3.2 Hz.The corresponding peak value for the operator cabin chassis was 0.425 m s −2 at 4 Hz.At 414 kPa, there was potential health risk on the operator for exposures above 8 h duration. The vibration total values recorded for the operator seat at the maximum tyre inflation pressure setting were classed as “fairly uncomfortable” (ISO standard 2631-1), and vertical seat vibration transmissibility was highest between 4 and 8 Hz at the 345 kPa tyre pressure setting. The recorded values of WBV were significantly reduced by a reduction in tyre inflation pressure which may therefore be used to moderate the magnitude of WBV on wheeled timber harvesters.