An Onboard Load Measuring Device for Off-Highway Log Trucks

Abstract

This paper was motivated by the current concern of brake failure in off-highway log trucks descending steep grades and the lack of onboard weighing systems for off-highway log trucks. This paper considers using the leaf spring U-bolts as load transducers and is divided into two stages: preliminary strain measurement with a partially loaded off-highway tractor and finite element modelling (FEM) of a U-bolt from the tractor’s leaf spring suspension. Preliminary results showed that incremental strain at two locations on the U-bolt varied linearly with payload, for an incremental load of 22.5 kN. FEM of the U-bolt was carried out to predict the maximum incremental strain occurring on the U-bolt surface for an incremental load of 105 kN. Incremental strain on the top of the curved portion of the U-bolt was found to be relatively constant and close to the maximum level of incremental strain and is recommended as a preferred position for the strain gauges.