Table 1. Vehicle sinkage and snow density data (after Richmond et
al. 1990).
Contact
Snow
Initial
Rut
pressure*
depth
Sinkage
density
density
(Mg/m3)
(Mg/m3)
Vehicle
(kPa)
(cm)
(cm)
HMMWV†
101.8
15.0
8.0
0.20
0.38
123.3
15.0
8.0
0.20
0.48
101.8
19.5
11.9
0.20
0.47
123.3
19.5
13.8
0.20
0.50
101.8
23.5
19.1
0.20
0.535
123.3
23.5
21.0
0.20
--
101.8
19.5
14.5
0.20
0.455
123.3
17.5
13.1
0.20
0.470
101.8
18.0
14.5
0.20
0.445
123.3
18.0
13.0
0.20
0.475
101.8
13.0
9.0
0.12
0.320
123.3
12.0
8.5
0.12
0.410
101.8
19.5
14.0
0.12
--
123.3
18.0
14.0
0.12
--
123.3
10.0
9.0
0.19
0.575
HEMTT**
233
20.0
12.4
0.25
0.490
230
21.0
16.9
0.25
0.440
225
20.0
16.2
0.25
0.520
218
20.0
15.6
0.25
0.460
233
16.5
12.4
0.25
0.490
230
18.0
13.2
0.25
0.490
225
20.5
15.4
0.25
0.510
218
20.0
15.6
0.25
0.510
233
20.0
14.3
0.245
--
218
17.0
12.6
0.245
0.460
233
13.0
10.0
0.12
--
HEMTT††
177
17.0
12.6
0.245
0.510
174
18.0
15.1
0.245
0.525
224
17.5
14.6
0.245
0.430
212
16.0
13.1
0.245
0.455
212
16.0
12.2
0.245
0.455
212
4.0
3.0
0.095
--
177
12.0
10.5
0.12
0.300
212
11.0
9.0
0.12
0.315
*Contact pressure of the wheel behind which the rut density measurement was made.
†With an inflation pressure of 137.9 kPa (front) and 151.7 kPa (rear).
**With an inflation pressure of 241.3 kPa (front two axles), 275.8 kPa (rear two axles).
††With an inflation pressure of 137.9 kPa (front two axles) and 206.8 kPa (rear two axles).
Tests were conducted at the Keweenaw Re-
A static calibration procedure (Shoop 1992) was
search Center of the Michigan Technological Uni-
used. Prior to collecting data in the snow, we
versity, in northern Michigan, during January and
conducted at least four tests on hard surfaces.
February 1993. The testing areas had been graded
These hard surfaces were sometimes covered with
free of vegetation prior to any snowfall, and were
packed snow or ice; however, an attempt was
nearly level. A layer of packed snow was beneath
made to use areas that were as smooth as possible.
the undisturbed snow in which the tests were
These hard surface data were averaged for each
conducted. The CIV was equipped with Michelin
load cell and used to remove from the subsequent
LT 235XCH4 tires for these tests.
snow resistance data the hard surface rolling resis-
Initial tests were done with the tires inflated at
tance and any zero offset (remaining from the
103 kPa (15 lb/in.2), while most of the tests were
static calibration) in the load cells.
run at an inflation pressure of 179 kPa (26 lb/in.2).
In these tests the vehicle was towed with all four
Tire data are in Table 2.
hubs locked out. During initial calibration tests,
2
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