influence road surface charactertistics on rolling resistance
TRANSCRIPT
influence of road surface characteristics on rolling resistance
Authors: dr. G.J.van Blokland, M+P (NL), ir. W. Schwanen, M+P (NL)
S.W. Boere, student TU/e (NL)
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Tentative study on effects of different road surfaces on rolling resistance and the relation with rolling noise and wet grip
Test programtest procedureroad surface typesmeasurement results
Rolling resistance explained with surface characteristicsroad surface textureroad surface mechanical impedance
Relation of rolling resistance withwet griprolling noise
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Rolling resistance
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Test vehicle
Designed and operated by TU Gdansk
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Test vehicle: Schematic representation
)tan(θNFRRC r ==
direct measurement system
θ : orientation of Arm 1
load adjustment system
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Test surfaces
Kloosterzande test track in the Netherlands40 different test tracks
ISO 10844SMA (0/6, 0/8, 0/11 and 0/16)Dense Asphalt Concrete 0/16Semi-porous thin layered surfaces Porous Asphalt Concrete with various stone-sizes and layer thicknesstwo-layer Porous Asphalt Concrete with different stone-sizes and layer thicknesseight experimental rubberized surfacestwo surface dressings
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Typical resultRolling resistance level as function for distanceGrey area is dominated by transient effectstwo different tyres
Uniroyal Tigerpaw (SRTT) 225/60 R16Continental CPC2 LI98 225/60 R16
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Test results: average rolling resistance Results for Continental tyre in categorical sequence (average over 5 measurements)Error bars indicate peak-to-peak levels
0.60%
0.80%
1.00%
1.20%
1.40%
1.60%
1.80%
2.00%
2.20%
1 19 20 21 22 23 2 3 4 5 6 7 8 9 15 24 31 38 10 11 12 13 14 16 25 26 27 28 29 30 17 18 32 33 34 35 36 37 40 41
ISO SMA DACThin layeredasphalt
PAC double layer PAC rubberized surfaces surfacedressings
Section
Rol
ling
Res
ista
nce
Coe
ffici
ent [
-]
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Test results: average rolling resistance Results for SRTT tyre in categorical sequence (average over 5 measurements)Error bars indicate peak-to-peak levels
0.60%
0.80%
1.00%
1.20%
1.40%
1.60%
1.80%
2.00%
2.20%
1 19 20 21 22 23 2 3 4 5 6 7 8 9 15 24 31 38 10 11 12 13 14 16 25 26 27 28 29 30 17 18 32 33 34 35 36 37 40 41
ISO SMA DAC Thin layeredasphalt
PAC double layer PAC rubberized surfaces surfacedressings
Section
Rol
ling
Res
ista
nce
Coe
ffici
ent [
-]
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Test results: comparison between tyresscatter diagram of rolling resistance results of both tyrespositive correlation : R2 = 0.99, slope = 1.07, residue = 0.02,
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
2.20
0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20
Continental
SRTT
ISOSMADACThin layered asphaltPACdouble layer PACrubberized surfacessurface dressings
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Surface texture
3-D laser profilometer:
•2.95 x 0.3 m area
•0,3 mm step and 20 μm resolution
12481631.56312520020
25
30
35
40
45
50
55
60
65
Wavelength [mm]
Text
ure
Am
plitu
de [d
B] (
Ref
. = 1
0 -6
m)
S19: 20 mm SMA 0/6S20: 25 mm SMA 0/8S21: 30 mm SMA 0/11S22: 40 mm SMA 0/16
rms = effective amplitude of surface texture
rmsSMA 0/6 0.53SMA 0/8 0.88SMA 0/11 1.16SMA 0/16 1.37
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Surface texture and rolling resistance
Correlation between rms of surface texture and rolling resistance coefficient. Various colors indicate the surface types, slope =0.078 %/mm , R2 =0.89 , residue = 0.016
rubberized surfaces
surface dressings
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Mechanical Impedance : measurement principle
measurement in labfrequency range 125 – 4 kHzpresented result is an average over 20 excitations
harmonic excitation :F(t)=F0*sin(2πf*t)result
stiffness of road surfaceadmittance
rolling resistance:frequency range of interest :250 – 400 Hz
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Mechanical impedance differences in mechanical behavior of flexible surfaces in frequency area relevant for rolling resistance
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Rolling resistance and mechanical impedance
0.60%
0.80%
1.00%
1.20%
1.40%
1.60%
32 33 34 35 36
S ectionRolling res
istance
coefficien
t [%
]
•influence of damping on rolling resistance ?
•part of the differences explained by difference in damping
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Rolling resistance and wet grip
results of ten surfaces including rubberized surfaces
0.6
0.8
1.0
1.2
1.4
1.6
0 0.2 0.4 0.6 0.8 1Wet Grip [-]
Rol
ling
Res
ista
nce
Coe
ffici
ent [
%]
40 mm DAC 0/1650 mm PAC 0/16double layer PACrubberized surfaces
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Rolling resistance and tyre/road noise
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rolling resistance and tyre/road noise subset of dense surfaces
relation on previous sheet spoiled by effect of acoustic absorption and elasticitysubset of test sections with no absorption and high mechanical impedance
slope = 0.21 [%/dB]
R2 = 0.79
residue = 0.14
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Conclusions
Road Surface Characteristicsgood correlation between rms of texture profile and rolling resistanceoutliers are surface dressings and elastic rubberized surfaces
Rubberized surfacesthe real part of the admittance measure for energy dissipationin relevant frequency range (250 – 400 Hz) higher energy dissipation corresponds to higher rolling resistance
Effect of rolling resistance of road surfacesIn this study we found no correlation between wet grip and rolling resistance for road surfacesFor dense surfaces a positive correlation between rolling noise and rolling resistance was found
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Recommendations
It shall be generally acknowledged that road surface characteristics have a significant effect on the rolling resistance of tyresImproving sustainability of road transport shall therefore incorporate both acoustic and fuel efficiency properties of road surfacesMeasurement methods, test procedures and evaluation criteria arerequired for large-scale implementation Integrated study’s on the basic interaction process between tyre and road incorporating safety effects, shall be initiated on short notice