This article is taken from (Soofastaei et al., 2018).
The rolling resistance (RR) is a major component of total resistance (TR), and it is one of the main controllable effective parameters for haul truck fuel consumption. TR is equal to the sum of RR and grade resistance (GR) when the truck is moving against the grade of the haul road.
RR depends on the tyre and hauling road surface characteristics and is used to calculate the rolling friction force, which is the force that resists motion when the truck tyre rolls on the haul road. GR is the slope of the haul road, measured as a percentage and is calculated as the ratio between the rise of the road and the horizontal length.
GR is positive when the truck is travelling up the ramp, and it is negative when it travels down the ramp. RR is defined as a measure of the force required to overcome the retarding effect between the tyre and road. This resistance is predominantly measured as a percentage of the GVW but can also be expressed as energy divided by a distance or force.
Tyre RR can also be characterised by a rolling resistance coefficient (RRC), a unit-less number. RR manifests itself predominantly in the form of hysteresis losses described as the energy lost, usually in the form of heat, when a section of vulcanised rubber is regularly deformed, such as during the operation of a haul truck.
The parameters affecting RR can be categorised into four groups: road, tyre, system and weather properties. The effective parameters on RR are also categorised into the design (D), construction (C), operational (O) or maintenance (M) parameters. The surface material of the haul road is a major contributor to RR.
Table 1 illustrates the parameters affecting RR, and their categories.
|
Rolling resistance |
Group | Categorya | Parameter | |||
| D | C | O | M | |||
| Road | ✓ | ✓ | Roughness | |||
| ✓ | ✓ | ✓ | Defects | |||
| ✓ | ✓ | ✓ | Material density | |||
| ✓ | Moisture content | |||||
| ✓ | Road maintenance | |||||
| Tyre | ✓ | ✓ | ✓ | Tyre penetration | ||
| ✓ | Tyre diameter | |||||
| ✓ | Tyre pressure | |||||
| ✓ | ✓ | ✓ | Tyre condition | |||
| ✓ | Tyre loading | |||||
| ✓ | Tyre temperature | |||||
| System | ✓ | Truck speed | ||||
| ✓ | Driver behaviour | |||||
| Weather | ✓ | Humidity | ||||
| ✓ | Precipitation | |||||
| ✓ | Ambient temperature |
aD: Design C: Construction O: Operational M: Maintenance
Reference
Soofastaei, A., Karimpour, E., Knights, P., & Kizil, M. (2018). Energy-Efficient Loading and Hauling Operations (K. Awuah-Offei, Ed.; pp. 121–146). Springer International Publishing. https://doi.org/10.1007/978-3-319-54199-0_7
