JST Vol. 21 (1) Jan. 2013 - Pertanika Journal - Universiti Putra ...

Modelling of Motion Resistance Ratios of Pneumatic and Rigid Bicycle Wheels
TABLE 7: Determination of the factors between motion resistance ratio of the pneumatic wheel obtained
by empirical and analytical methods at different dynamic loads and 414 kPa
Dynamic Load
(N)
98.1
196.2
392.4
A: MRR (Empirical) B: MRR (Analytical) C: Factors (A/B)
Tilled wet Tilled Wet Tilled Wet
0.0878 0.2540 0.0527 0.0474 1.6660 5.3586
0.1108
0.1041
0.2250
0.2332
0.0504
0.0518
0.0472
0.0482
588.6 0.1116 0.1945 0.0501 0.0495 2.2275 3.9293
Mean 2.0254 4.7233
Coefficient of variation 12.758% 12.52%
Inflation Pressure, P = 414 kPa and Overall Wheel Diameter (metallic rim), D = 660mm.
Field Condition: Tilled Surface (Sandy-Clay-Loam Soil)
Added Dynamic Load range: 98.1 – 588.6 N
Field condition: Wet soil (sandy-clay-loam soil) surface
Added dynamic load range: 98.1 – 588.6 N
From Brixius’ (1987) equation for bias-ply tractor tyres, the motion resistance ratio is as
stated in Equation 5. Therefore, for the 660 mm pneumatic bicycle wheels at 414 kPa inflation
pressure, the motion resistance ratio was derived as follows:
1
MRR ( Bicycle ) = 4.7233 (0.04 + )
B
4.7233
MRR( Bicycle)
= 0.1889+
B
From Brixius’ (1987) equation for bias-ply tractor tyres, the motion resistance ratio is as
stated in Equation 5. For the rigid bicycle wheel on tilled surface, the motion resistance ratio
was therefore derived as follows:
Pertanika J. Sci. & Technol. 21 (1): 283 - 298 (2013)
n
n
2.1984
2.0097
4.7669
4.8382
TABLE 8: Determination of the factors between motion resistance ratio of the rigid wheel obtained by
empirical and analytical methods at different dynamic loads
Dynamic Load
(N)
98.1
196.2
392.4
A: MRR (Empirical) B: MRR (Analytical) C: Factors (A/B)
Tilled wet Tilled Wet Tilled Wet
0.1778 0.3180 0.0515 0.0578 3.4524 5.5017
0.1704
0.1818
0.3513
0.2605
0.0529
0.0646
0.0606
0.0662
3.2212
2.8142
5.7970
3.9350
588.6 0.2431 0.2637 0.0797 0.0675 3.0502 3.9067
Mean 3.1345 4.7851
Coefficient of variation
Field Condition: Tilled Surface (Sandy-Clay-Loam Soil)
8.60% 21%
Added Dynamic Load range: 98.1 – 588.6 N
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