Estimation of Trafficable Grades from Traction Performance of a Forwarder

• Main Author: Jörg Hittenbeck
• Format: Article
• Language: English
• Published: University of Zagreb, Faculty of Forestry 2013-01-01
• Series: Croatian Journal of Forest Engineering
• Online Access: https://hrcak.srce.hr/file/172579

Wood as a renewable resource is getting more and more popular for material use as well as for energy usage. In order to meet the demands, it is important to make previously unused wood potentials accessible to the timber market. One area of interest is the incompletely utilized resources in inclined regions. Problems arise in these areas by the topographic limitations of highly mechanized timber harvesting. These limitations occur from the stability of the machine as well as from the damages done to the soils. Considerations about the downhill slope forces acting on the machines show a direct relation between the inclination of a grade and the traction coefficient. In theory, it seems possible to calculate a trafficable grade for an accepted level of wheel slip. On the basis of a 25% slip limitation, a model for trafficable grades was developed and tested for typical hillside conditions. Measurements of traction force vs. slip identified the soil water content and the skeletal rate as the main soil parameters that affect the climbing ability of machines. Test drives in inclined terrain indicated that the approach of calculating limitations (for trafficable grades) from traction tests under level conditions lead to a fairly good prediction.