اثر سرعت پيشروي بر مقاومت حركتي چرخ هاي لاستيكي

The Effect of Forward Speed on Motion Resistance of Rubber Tires

Much research has heen performed in the world on traction mechanics and parameters affecting it, lind many traction prediction models were developed, but in none ofthem the etfecr of forward speed has been taken into account. In this research, traction performance measured values or a rubber tire were compared with the same traction performance values that were calculated by three most common prediction models, and in addition the effect of forward speed on traction perfcruance parameters were measured and evaluated. Tests were performed hy fabrication of a laboratory soi/bin. Data acquisition was carried out by an instrumentation system consisting or sensors, amplifiers, data logger, and PC. Independenl variables were three levels of tor-..vard speeds, three levels of normal loads, six levels of soil strengths and three levels of slips. Dependent variables were net traction (NT), gross traction (GT), motion resistance (lv/IO and traction efficiency (TE). Camparison and evaluation of data were carried out by using a factorial experiment on the basis of randomized compelet block. design with three replications. Interactions of independent and dependent variables in addition to verification of previous research results showed that forv...ard speed has high significant effect on motion resistance. Based on lest results, a regression model tor motion resistance ratio (MRR) was developed which ill audition previous models, the toward speed and slip parameters were also cntcrd in the new model. The newly developed motion resistance ratio model is: MRR ~ ~...29 _ 0.0 15Va+ 0.35S + 0.023 Where Va is actual forward speed in km/ (~7 /hʹ S is slip in decimal and en is dimentionless mobility number.