aussie def veh mob cat

COMMONWEALTH OF AUSTRALIA

AUSTRALIAN DEFENCE STANDARD

DEF(AUST)8033 / Issue 2Dated 17 Feb 2006

MOBILITY CATEGORIES;

DEFENCE STANDARD

*PUBLISHED UNDER AUTHORITYOF DEPARTMENT OF DEFENCE

Usage Land

POULOPOV

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DEF(AUST)8033 / Issue 2

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Defence Group Army

Sponsoring Organisation DMO

Sponsoring Coordinator LEA

Sponsoring Appointment Land Vehicle Systems Program Office

Standardisation Committee Army Standardisation

Published by: Army Standardisation

AMENDMENT LIST

AMENDMENT

No Date of IssueDescription

Draft A 4 Dec 03 First DraftDraft B 17 May 05 Definition of AAP addedIssue 1 25 Oct 05 First IssueIssue 2 17 Feb 06 Equation for VCI estimate in Annex B corrected and its

applicability clarified. Page numbering for Annex Ccorrected.


AUSTRALIAN DEFENCE STANDARD

DEF(AUST)8033 Issue 2

MOBILITY CATEGORIES;

STANDARD

17 FEB 2006

Specific inquiries regarding the application of this Specification to Requests for Tender orcontracts should be addressed to the Procurement Authority named in the Request for Tender,or to the Quality Assurance Authority named in the contract, as appropriate.


TABLE OF CONTENTS

PARAGRAPH CONTENT PAGE

1. PURPOSE 1

2. BACKGROUND 1

3. SCOPE 1

4. DEFINITIONS 2

5. THE REFERENCE TERRAIN DATA SET 2

6 BENCHMARK VEHICLES 2

7. MOBILITY CATEGORY DEFINITIONS 3

8. DETERMINING MOBILITY CATEGORIES 4

9. ADDITIONAL VEHICLE CHARACTERISTICS 4

10. APPLICABLE DOCUMENTS 5

11. INQUIRIES 5

ANNEX A SUPPORTING INFORMATION CONCERNING THEREFERENCE TERRAIN DATA SET

ANNEX B VEHICLE DATA GUIDANCE SECTION

ANNEX C LEA-NRMM VEHICLE DATA INPUT

ANNEX D LEA-NRMM SCENARIO INFORMATION

ANNEX E AVERAGE ABSORBED POWER


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1. PURPOSE

1.1 The purpose of this specification is to define an objective method for specifying the level ofoff-road mobility for ground vehicles. The method has been designed to be performancebased rather than prescriptive. The specification also provides guidance on the influence ofseveral vehicle characteristics on off-road mobility. Guidance is also given on thecharacteristics of the terrain that is intended to be representative of the land portion of theAustralian Defence Force’s Area of Direct Military Interest.

1.2 The specification aims to assist capability development, preparation of specifications,preparation of tenders, tender evaluation, and the end-user of ground based mobileequipment.

2. BACKGROUND

2.1 The Land Engineering Agency (LEA) was tasked by the Defence Materiel OrganisationMobility Systems Program Office (DMO-MSPO) to review Defence’s mobility categoriesfor vehicles. This task was (in part) a response to the Department of Defence’s agreementto an Australian National Audit Office (ANAO) recommendation which stated:

“The ANAO recommends that, to better match vehicle capabilities to required tasking andto assist in decision making, Defence develop a set of mobility categories including criteriaand parameters that can be objectively measured.”

2.2 The system described herein satisfies the ANAO requirement. It specifies that the LandEngineering Agency NATO Reference Mobility Model (LEA-NRMM) be used to analysevehicle performance over a specific reference terrain data set and that measures for wetseason no-go and dry season speed be used to objectively place a vehicle in a particularmobility category.

2.3 The specification limits were obtained using a procedure that followed the steps below:

a. A preliminary categorisation for each vehicle in a benchmark vehicle set wasdetermined using subjective assessment by a panel of experts.

b. LEA-NRMM prediction on the Army’s reference terrain data set was performed foreach vehicle and the level of off-road wet season trafficability and dry season speedwere obtained.

c. The final mobility classification limits were based on an analysis of the nature ofclustering of predicted levels of performance according to the preliminarycategorisation.

2.4 This document will be periodically revised when significant improvements to the ReferenceTerrain Data Set or the benchmark vehicle set are made available. The ultimate aim of theReference Terrain Data Set is to be representative of the Defence Force’s Area of DirectMilitary Interest.


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3. SCOPE

3.1 This specification deals solely with the issue of off-road mobility and presents a means toquantify it.

3.2 Mission profiles, or the proportion of time spent operating on-road, on tracks, and off-roadshould be considered separately to off-road mobility performance and be based on therequirements of the end user. In the absence of such stated requirements, guidance relatingmobility categories to mission profiles for reliability testing is given in Def(Aust)5681,Environmental Test Standard For Land Based Equipment.

4. DEFINITIONS

4.1 Trafficability: The ability of a vehicle to traverse terrain, either go or no-go. It is usuallyreported as a percentage of navigable terrain for a specified area.

4.2 Speed-made-good: The straight-line distance between start and destination points dividedby the total travel time.

4.3 Mobility: A measure of the automotive performance of a vehicle based on, and only on,considerations of trafficability and speed-made-good over specified terrain.

4.4 Nominal Average Speed/Velocity (NAV): LEA-NRMM is often used to plot the maximumachievable speed of a vehicle against the cumulative percentage of area, up to the point atwhich the terrain is not navigable. The nominal average speed is the mean of the maximumachievable speed taken over the navigable area.

5. THE REFERENCE TERRAIN DATA SET

5.1 The Reference Terrain Data Set that forms the basis for the Mobility Category definitions isdescribed in Annex A Below.

6. BENCHMARK VEHICLES

6.1 120 military vehicles were used as the benchmark to determine the Mobility Categories.The vehicles tended towards the highly mobile end of the performance spectrum with theresult being that the limits between MC1, MC2 and MC3 could be established with moreconfidence than the limit between MC3 and MC4.

6.2 The distribution of as modelled vehicle mass for the benchmark vehicle set is shown infigure 1. Most vehicles were laden to their Gross Vehicle Mass condition.


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Figure 1 - Mass Distribution for Benchmark Vehicles

05

101520253035

0 to 1

1 to 2

2 to 5

5 to 1

0

10 to

15

15 to

20

20 to

30

30 to

40

40 to

50 50+

Mass Class (t)N

o in

sam

ple

6.3 The vehicles represent all LEA-NRMM data sets currently held by the Land EngineeringAgency at Dec 2002 and represent a range of fighting, logistics vehicles, and engineeringvehicles both tracked and wheeled.

6.4 Information concerning the benchmark vehicles and relationships between some vehicleparameters and Mobility Category is given at Annex B.

7. MOBILITY CATEGORY DEFINITION

7.1 The major discriminator for Mobility Category is wet season trafficability, a measure of theamount of terrain a vehicle is able to negotiate. Wet season trafficability determines thelimits between MC1, MC2, MC3 and MC4. The top two categories, MC1 and MC2 arefurther divided into high (‘H’) and low (‘L’) sub-categories. These sub-categories areintended to identify vehicles that are able to sustain high off-road speeds. The limit betweenthe high and low categories is based on the average maximum speed the vehicle is able toachieve over the reference terrain in the dry season.

7.2 The Mobility Category definitions are presented in table 1 below:

Table 1 - Mobility Category Definitions

MobilityCategory Description

Specification Limits(based on LEA-NRMM

Predictions overReference Terrain Data

Set)MC1-High Able to make maximum use of terrain to

enable rapid deployment to optimal firingpositions, weapon sites, surveillance pointsetc. and be able to out-manoeuvre highlycapable threat vehicles

Wet Go ≥ 83%

Dry NAV ≥ 25km/h

MC1-Low Able to make maximum use of terrain toenable routine deployment to optimal firingpositions, weapon sites, surveillance pointsetc

Wet Go ≥ 83%

Dry NAV < 25km/h

MC2-High Able to make use of terrain to enable rapiddeployment to good firing positions,weapon sites, surveillance points etc

Wet Go ≥ 77%Wet Go < 83%

Dry NAV ≥ 25km/h


4

Table 1 - Mobility Category Definitions

MobilityCategory Description

Specification Limits(based on LEA-NRMM

Predictions overReference Terrain Data

Set)MC2-Low Able to make use of terrain to enable

routine deployment to good firingpositions, weapon sites, surveillance pointsetc.

Wet Go ≥ 77%Wet Go < 83%

Dry NAV < 25km/hMC3 Sufficient off-road capability to reach

support echelons, distribution points,worksites and circumvent road damage orblockages.

Wet Go ≥ 60Wet Go < 77%

MC4 Limited off-road mobility (Wet Go < 60%)NAV = Nominal Average Speed Based on LEA-NRMM Prediction

8. DETERMINING MOBILITY CATEGORIES

8.1 Mobility Categories can only be authoritatively determined using the Land EngineeringAgency’s version of the NATO Reference Mobility Model (LEA-NRMM) and theassociated Reference Terrain Data Set. This can be accomplished through a request to LEAand requires submission of vehicle data to LEA-NRMM input specifications as detailed inAnnex C.

LEA Manoeuvre Systems Program – Engineering Specialist4th Floor Defence Plaza661 Bourke StVIC 3000AustraliaPh:+61 (0) 3 9622 2860, Fax: +61(0) 3 9622 2940

8.2 Scenario information used to perform the Mobility Categories LEA-NRMM analysis isgiven at Annex D. This information must be used in order to obtain valid results.

8.3 There is a Guidance Section which discusses vehicle data at Annex B. This section can beused to assist in estimating a vehicle’s Mobility Category.

9. ADDITIONAL VEHICLE CHARACTERISTICS

9.1 LEA-NRMM takes a systems approach to mobility prediction taking most vehiclecharacteristics into account. However there are limits to the engineering detail that themodel uses for these predictions. Three parameters have been identified that require explicitspecification in addition to the Mobility Category:

9.1.1 Between Kerbs Turning Circle;

9.1.2 Static Overturn Angle;

9.1.3 Fording Depth.


5

9.2 Guidance for specifying these parameters is included in tables 2 and 3, and aligns with thatspecified in UK Defence Standard 23-6, Guide to the Common Technical Requirements offor Military Logistics Vehicles and Towed Equipment.

9.3 It should be noted that the values given in Tables 2 and 3 are for Military LogisticsVehicles. Corresponding guidance for Fighting Vehicles is not available although it isrecognised that they often require and exhibit superior characteristics with regard to theseparameters.

9.4 Where statutory requirements are more stringent than the guidance proposed herein, theywill take precedence.

Table 2 - Turning Circle and Overturn Angle GuidanceMaximum Turning Circle(metres, Between Kerbs)

Minimum Static OverturnAngle at First Wheel Lift

(degrees)Veh. MassClass1 (t):

<4 4 to 8 >8 <4 4 to 8 >8

MC1 11 16 18 35 33 33MC2 12 17.5 20/21.52 33 30 30MC3 13 19 22.5 30 28 28MC4 13 25 25 28 26 26

Table 3 – Fording Depth GuidanceMinimum Fording Depth (m)

Veh. MassClass1 (t):

<4 >4

MC1 0.75 1.25MC2 0.75 0.75MC3 0.75 0.75MC4 0.5 0.5

1 The Vehicle Mass Class is based on the vehicle’s payload.2 20m for up to three axles, 21.5m for 4 axles or greater or 15t payload or greater.


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10. APPLICABLE DOCUMENTS

10.1 This standard has made reference to the following related documents:

Australian Defence Standard

Def(Aust)5681 Environmental Test Standard For LandBased Equipment

UK Ministry of Defence Standard

Def Stan 23-6 Guide to the Common Technical Requirements of forMilitary Logistics Vehicles and Towed Equipment.

11. INQUIRIES

11.1 General inquiries and suggested amendments, should be addressed to:

Assistant Program CoordinatorArmy StandardisationLand Engineering Agency3rd Floor Defence Plaza, Melbourne661 Bourke StreetMELBOURNE VIC 3000

DEF(AUST)8033 / Issue 2ANNEX A

A-1

ANNEX A

SUPPORTING INFORMATION CONCERNING THEREPRESENTATIVE TERRAIN DATA SET

1. INTRODUCTION

1.1 The mobility of ground vehicles differ due to variations of terrain parameters such as slope,soil strength, surface roughness, obstacles, vegetation stem size and spacing, visibility etc.The Mobility Categories are based upon the digital terrain database developed to berepresentative of Northern Australia. The map sheets listed in Table A-1 represent theactual area covered by the Representative Terrain Data Set, which is predominantly theregion extending from Darwin to Katherine. The following terrain attributes have beenextracted from the database to show their percent area distribution:

a. Soil Strength for Dry and Wet conditions;

b. Slope;

c. Surface Roughness;

d. Vegetation Density;

e. Obstacle Height.

1.2 The area covered by perennial water was not included in this analysis. Furthermore,separate consideration should be given to gap crossing, amphibious operation and sandydesert operation.

1.3 The quantitative values for each of the above terrain parameters have been groupedaccording to suitable class intervals.

(Table A-1) Mobility Terrain Database Summary

Database name Area (km2) 1:1250000 mapsheetDarwin ~12000 SD52-4 (4 1:100000 mapsheets)

Pine Creek 17935 SD52-8Fergusson River 5951 SD52-12 (2 1:100000 mapsheets)

Port Keats 11653 SD52-11Bradshaw 8710 Part of 4 1:250000 mapsheets SD52-11, 12, 15 &16

Katherine SP 2500 Part of two 1:100000 map sheets - Katherine and Manbulloo

2. SOIL STRENGTH

2.1 Soil strength has a significant impact on vehicle mobility on ground. While soil strength isdependent on soil type and moisture content, other significant factors such as the rainfalldepth, duration and intensity as well as soil drainage should be considered. The northernpart of Australia especially Katherine-Darwin region has two distinctive seasons mainly dryand wet. Generally high rainfall occurs during the period of December to April and ismainly dry for the rest of the year. It is also a fact that near the coast, rainfall intensity andduration is higher than that of the area away from the coast. In this analysis only dry-seasonand wet-season soil strengths are reported.


A-2

Dry Season Soil Strength

2.2 From Table 2 it is clear that significant areas of Northern Australia in the Dry Season(nearly 95%) have high soil strength due to limited soil moisture. The saline coastal inter-tidal zones, intermittent streams, billabongs and swamps covering slightly over 5% of thearea show low soil strength due to saturated soils of clayey nature. About 95% area hasindicated soil strength more than 200 CI (Cone Index) which is sufficiently strong enough toallow multi-passes of any type of vehicles.

Table 2: Per cent Area for Dry Soil Strength Class (within LEA-NRMM Terrain DatabaseArea)

Wet Season Soil Strength

2.3 In comparison the soil strength during wet periods has a considerable variation. Thedistribution is roughly uniform except for some non-occurrence classes according to Table 3as presented below. Large portions of the area exhibit soil strengths lower than 100 CI, avalue that can cause problems for vehicle mobility.

Table 3: Per cent Area for Wet Soil Strength Class (within LEA-NRMM Terrain DatabaseArea)

Class Soil Strength Area % AreaNumber (RCI/CI) (km2)

1 300 - 281 6405.99 12.492 280 - 221 0 03 220 - 161 0 04 160 - 101 1316.12 2.575 100 - 61 12,378.45 24.146 60 - 41 13,475.00 26.277 40 - 33 721.15 1.418 32 - 26 2126.06 4.159 25 - 17 7577 14.7710 16 - 11 0 011 10 - 4 7285.24 14.21

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11Soil Strength Class

% A

rea

Class Soil Strength Area % AreaNumber (RCI/CI) (km2)

1 300 - 281 48,442.59 94.462 280 - 221 0.96 03 220 - 161 0.04 04 160 - 101 0 05 100 - 61 0 06 60 - 41 0 07 40 - 33 0 08 32 - 26 0 09 25 - 17 1726.03 3.3710 16 - 11 0 011 10 - 4 1116.24 2.18

0102030405060708090

100

1 2 3 4 5 6 7 8 9 10 11

Dry Soil Strength Class

% A

rea


A-3

2.4 The majority of soils found in low lying areas are rich in clays and silts and these soils inconjunction with the high water table and poor internal drainage are responsible for soilstrength below 100 CI/RCI. Some areas remain inundated for a longer period.

3. SLOPE

3.1 The high slope in combination with low soil strength and dense vegetation offer the greatestresistance to vehicle mobility. Slope alone above 70% is not negotiable by most vehicles.In current database area, high slopes are mainly encountered for features such asescarpment, cliff, hanger, vertical wall and large gaps of rivers, creeks and gorges. Ingeneral Northern Australia has vast tracts of level to undulating lands and plateaus. Morethan 85% of the area has slope less than 5%. However these vast areas also exhibit highpercentages of obstacles and high surface roughness values that have a detrimental effect onvehicle mobility.

Table 4: Per cent Area for Slope Class (within LEA-NRMM Terrain Database Area)

4. SURFACE ROUGHNESS

Table 5: Per cent Area for Surface Roughness Class (within LEA-NRMM Terrain DatabaseArea)

4.1 Generally surface roughness is generated from the departure of height (elevation) from theheight of imaginary line after the adjustment for the prevailing slope at a regular interval ofcontour sections or survey points. This is reported in Root Mean Square (RMS) in inches ofmultiple of 10. Therefore rugged terrain in general has high surface roughness due topresence of continuous cover of rock fragments. For the Reference Terrain Data Set, the

Slope Class Slope (%) Area in % AreaNumber (km2)

1 1 - 2 34,703.82 67.672 3 - 5 9318.04 18.173 6 - 10 3965.22 7.734 11 - 20 2192.73 4.285 21 - 40 793.66 1.556 41 - 60 30.43 0.067 61 - 70 1.11 08 > 70 280.85 0.55

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1 2 3 4 5 6 7 8

Slope Class

% A

rea

Class Number

RMS (inch x 10)

Area (km2) % Area

1 1 980.5 1.912 2 - 4 6039.54 11.783 5 - 6 17,115.68 33.374 7 - 8 18,418.63 35.915 9 - 12 3377.64 6.596 13 - 16 1890.35 3.697 17 - 22 0 08 23 - 32 3463.52 6.75

05

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1 2 3 4 5 6 7 8Surface Roughness Class

% A

rea


A-4

RMS class distribution is close to uniform. However, the values are highly localised anddepend greatly on the weathering process and surface covers.

5. OBSTACLE HEIGHT

5.1 In LEA-NRMM database obstacle geometry is defined by the following parameters:obstacle height; base width; approach/departure angle; spacing as well informationindicating them as randomly occurring or linear features. Their impact on mobility is aresult of the combination of the five parameters however in the absence of a better measure,height data only has been chosen for presentation. The distribution is skewed towards thelower height as many areas have very low obstacles. For example forest areas on most soilshave limited rocks but may have logs and stumps, while open grasslands may have tussocksor hummocks that have low obstacle height.

Table 6: Per cent Area for Obstacle Height Class (within LEA-NRMM Terrain Database Area)

6. VEGETATION DENSITY

6.1 The LEA-NRMM digital database requires stem spacing and stem diameter classes torepresent vegetation. It is difficult to interpret data based on this multi-variable approach sothe proportion of broad vegetation groups based on common descriptors has been provided.

Class Obstacle Area in % AreaNumber Height (inch) (km2)

1 7.60 - 15.50 27,438.01 53.52 16.00 - 25.50 15,865.81 30.943 26.00 - 35.50 1540.6 34 36.00 - 46.00 1716.04 3.355 46.50 - 61.00 979.38 1.916 61.50 - 83.50 1198.22 2.347 84.00 - 115.00 2547.8 4.97

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1 2 3 4 5 6 7

Obstacle Height Class

% A

rea

Vegetation Density % AreaDense forest 1.2

Medium forest 23.25Scattered forest 62.5Grassland/Open 9.6

Others (urban, water etc) 3.45

DEF(AUST)8033 / Issue 2ANNEX B

B-1

ANNEX B

VEHICLE DATA GUIDANCE SECTION

1. The following table presents a number of vehicle parameters that are important in relation to off-roadmobility. The mean values and standard deviation of the parameters for the benchmark vehicles areplotted against Mobility Category. The mean gives a typical measure for a particular parameter againstMobility Category. The mean +/- the standard deviation gives an indication of the range of values of aparticular parameter. About 68% of the sampled vehicles in a Mobility Category exhibit values for thatparameter within the mean +/- the standard deviation.

2. The table can be used as a guide to help estimate the probability of a vehicle falling into a particularMobility Category. Actual Mobility Category determination can only be accomplished through use ofLEA-NRMM.

Table B-1– The General Impact of a Selection of Vehicle Parameterson Mobility Category

KeyMean ValueMean + Standard DeviationMean – Standard Deviation

Figure B-1 – Departure angle is reasonablycorrelated to Mobility Category.

Departure Angle

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1 2 3 4Mobility Category

Dep

artu

re A

ngle

(deg

)

Figure B-2 – Approach angle is somewhatmore strongly correlated to MobilityCategory than departure angle.

Approach Angle

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App

roac

h A

ngle

(deg

)

Figure B-3 – Power to weight ratio has noreal correlation to trafficability. Rather itimpacts on speed-made-good as illustrated bythe correlation between the “H” or highcategories and increased power to weightratio.

Power to Weight Ratio

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MC1-H MC2-H MC1-L MC2-L MC3 MC4Mobility Category

P/W

(kW

/t)

Mean + Std dev Mean Mean - Std Dev


B-2

Figure B-4 – Specific Tractive Effort is aratio of theoretical tractive effort (asdetermined by engine torque and drive-traingearing without regard to limitations imposedby wheel slip) and vehicle mass. MobilityCategory is significantly correlated withSpecific Tractive Effort.

Specific Tractive Effort

0

0.2

0.4

0.6

0.8

1

1.2

1.4


Spec

ific

TE (k

g/kg

)

Figure B-5 – This figure plots the maximumheight of a platform with vertical sides overwhich the benchmark vehicles could drive onand off. The values are the results of LEA-NRMM predictions. There is significantcorrelation between Maximum Step Heightand Mobility Category.

On-Off Vertical Step

0

200

400

600

800

1000

1200

1400


Max

Ste

p H

eigh

t (m

m)

Figure B-6 – Ground Clearance is theminimum distance between any part of thevehicle (other than the wheels) and theground. There is some correlation betweenGround Clearance and Mobility Category.Break-Over Angle has similar implicationsand is probably a more appropriate measurebut data for this was not available.

Ground Clearance

0

100

200

300

400

500


Gro

und

Cle

aran

ce (

mm

)

Figure B-7 – Fine Grain VCI (Vehicle ConeIndex) is a measure of the strength of theweakest fine grain soil (e.g. clay) over whicha vehicle is capable of travelling. VCI isstrongly correlated to Mobility Category.See Paragraph 5 in this Annex for anequation to estimate VCI.

Limiting Soil Strength - Fine Grained

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1 2 3 4

Mobility Category

Soil

Stre

ngth

VC

I (ps

i)


B-3

Ride Quality - Continous Vibration - 6W AAP Criteria

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70 80 90 100 110 120Terrain Roughness (mm RMS)

Spee

d (k

m/h

)

Mean + Std Dev for "H" category vehicles

Mean - Std Dev for "H" category vehicles

Mean - Std Dev for "L" category vehicles

Figure B-8 – Generally ride quality is vehicle characteristic that has most influence onachievable speed off-road. LEA-NRMM uses two measures for ride quality: one is a plot ofthe speed achievable on continuous profiles of a range of roughnesses based on the driver’sAverage Absorbed Power (AAP, ref. Annex E). A six Watt AAP criterion is used. Terrainroughness is measure using the RMS of the profile filtered using a 20m wavelength high passfilter.

Ride Quality - Descrete Semi-circular Obstacles - 2.5 G Shock Criteria

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100

0 100 200 300 400 500Obstacle Height (mm)

Spee

d (k

m/h

)

Mean + Std Dev for "H" categoryvehiclesMean - Std Dev for "H" categoryvehiclesMean - Std Dev for "L" categoryvehicles

Figure B-9 – The second measure of ride quality is characterised by a plot of the speedachievable when traversing discrete semi-circular obstacles based on the impulse received bythe driver. For this measure, a 2.5 G peak vertical acceleration criterion is used.


B-4

3. The shaded areas in figures B-8 and B-9 represent the zones in which ride-curves typical of category ‘H’vehicles reside. The curve titled Mean – Std Dev for “L” category vehicles represents the lower limit ofride quality for the bulk of the “L” category vehicles in the benchmark vehicle set.

4. Ride quality can be defined separately in a vehicle performance specification. Speeds based on the abovecriteria can be specified against roughness or obstacle height values. The Accredited Test Services (ATS)Automotive and Electrical Performance Laboratory (AEPL) at Monegeetta, Victoria has continuousroughness courses of the following severity for measuring vehicle ride quality:

Table B-2 – AEPL Monegeetta RandomRide Courses

Profile designation RMS (mm)Profile 1 10.6Profile 2 16.0Profile 3, left lane 20.8Profile 3, right lane 18.8Profile 4, left lane 27.9Profile 4, right lane 35.6Profile 5, left lane 43.2Profile 5, right lane 48.3

5. Single pass VCI (psi) can be estimated for solo all wheel drive vehicles using the following formulas1:

TCFCPVCI ⋅+⋅+= 95.103.295.1

( ) ( ) ( ) 52.02026.0026.02 hbdddbn

wCP⋅⋅+−⋅+⋅⋅⋅

=δδ

Where:TCF = 0 if radial, or 1 if bias ply (Tyre Construction Factor)w = average axle loading (lbf)n = average number of tyres per axleb = average tyre section width (in)d = average tyre outside diameter, unloaded (in)δ = average hard surface tyre deflection (in)h = average tyre section height (in)

1 Reference: Improving the Traction Prediction Capabilities in the NATO Reference Mobility Model (NRMM),J.D. Priddy, Report No. GL99-8, US Army Corps Of Engineers Waterways Experiment Station, Aug 1999.

DEF(AUST)8033 / Issue 2ANNEX C

C-1

ANNEX C

LEA-NRMM VEHICLE DATA INPUT

COMPANY / ORGANISATION:VEHICLE / PROJECT NAME:CONTACT PERSON:TELEPHONE:FAX:

1.0 INTRODUCTION• The following specifies the data necessary for an accurate engineering description of the

vehicle• Note that all data are to be for a COMBAT LADEN vehicle unless otherwise stated• UNITS of all data supplied must be clearly stated

2.0 VEHICLE IDENTIFICATION2.1 Vehicle Name:

2.2 Vehicle Make:2.3 Vehicle Model:2.4 Description:

3.0 POWER TRAIN3.1 ENGINE3.1.1 Engine Description:3.1.2 Maximum Gross Power: at rpm3.1.3 Maximum Gross Torque: at rpm3.1.4 Cycle (2-stroke or 4-stroke):3.1.5 Fuel (Petrol or Diesel):3.1.6 Number of Cylinders:3.1.7 Total Displacement:3.1.8 Configuration (In-line, Vee etc):

Engine Torque-Speed curve: Provide a clearlylabelled curve of net flywheel torque for theengine in the installed condition with allaccessories, for the full operating speedrange. Include governor droop characteristics(if applicable) as per Figure 1. Alternatively,provide a Table of Engine Torque VersusSpeed in the full operating range. Please quotestandard used (eg. SAE J1349, ISO 1585)

(Example Illustrated)

3.2 TRANSMISSION3.2.1 Transmission Description:3.2.2 Transmission Type:

Manual with Clutch:Auto with Torque Converter:Other:

3.2.3 Does Torque Converter have Lockup:


C-2

3.2.4 Main Transmission Gear Ratios:3.2.5 Transmission Efficiency in Each Ratio:3.2.6 Is an Engine to Transmission Transfer Box

Fitted?If Yes, give Ratios and Efficiencies:

3.2.7 Is a Main Transmission to Axle Transfer BoxFitted?If Yes, give Ratios and Efficiencies:

3.2.8 If a Torque Converteris fitted, provide torqueconverter characteristiccurves as per figure 2and include data onpump torque applicableto installation.Alternatively, provide atable of data whichincludes the PUMP K-FACTOR, TORQUERATIO and SPEEDRATIO.

3.2.8 If non conventionaltransmission is fittedprovide a curve of wheeltractive effort for the fullvehicle road speedrange with engine at fullthrottle, (ie Tractiveeffort speed curve) asper Figure 3.(Do not includeaerodynamic or rollinglosses, but include alltransmission efficiencyeffects.)

3.3 FINAL DRIVE3.3.1 Final Drive Description:3.3.2 Axle Gear Ratio:

Axle Gear Efficiency:3.3.3 Are Wheel, or Hub Reductions Fitted?

If Yes, Gear Ratio:Efficiency:


C-3

3.3.4 Are Cross Axle Differential Locks Provided?If Yes, which Axle(s):Efficiency:

4.0 GENERAL DATA4.1 AXLES4.1.1 Number of Axle Assemblies:4.1.2 Which Axles are Powered:4.1.3 Which Axles are Braked:4.1.4 Maximum Allowable Gross Vehicle Mass

(GVM)4.1.5 Axle Loading at GVM (or for fighting vehicle at

actual Combat Laden condition) for each axle4.1.6 Axle Loading in Unladen condition (completely

ready for operation but without crew or payload)for each axle

4.1.7 Maximum rated loading for each axle

4.2 TYRES AND RIMS4.2.1 Description of Tyres fitted to each Axle, (Radial

or Bias ply)4.2.2 Manufacturer and designation

(eg. 365/85R16):

4.2.3 Tyre Section Height (undeflected) for eachAxle:

4.2.4 Tyre Section Width (undeflected) for each Axle:4.2.5 Tyre Ply or Load Rating for each Axle:4.2.6 No. of Tyres on each Axle:4.2.7 Wheel Rim Diameter for each Axle:4.2.8 Wheel Rim Width for each Axle:4.2.9 Outside Tyre Diameter (undeflected) for each

Axle:4.2.10 Is variable Tyre Pressure Device Fitted:4.2.11 Tyre Inflation Pressure for each Axle (GVM or

Combat Laden, specify for:Clay-Soil-Mud Operation:Sand Operation:Highway Operation:

4.2.12 Deflection of Tyres on each Axle, CombatLaden at Operating Pressures specified above:

NOTE An alternative to the above is to provide the tyre manufacturer’s data sheet that providestables with recommendations for tyre pressures against wheel load, terrain type (road, mudsand), and corresponding deflections speed limitations.

4.3 TYRE, AXLE RELATED DIMENSIONS4.3.1 Inter-axle distance (distance from centreline of

1st axle to 2nd axle, 2nd axle to 3rd axle etc):4.3.2 Minimum Ground Clearance at each Axle:4.3.3 Track Width (see Figures 4 & 5) for each Axle:4.3.4 Minimum Width between Tyres (Figure 6):4.3.5 Overall Width over Tyres (Figure 7):


C-4

4.3.6 Revolutions per mile of tyres for each (At GVMor combat laden & highway tyre pressure):

4.4 CENTRE OF GRAVITY (C of G)4.4.1 C of G height above ground (unladen):4.4.2 Lateral c of g distance from vehicle centreline

(left or right) as viewed from the rear (unladen):4.4.3 Longitudinal C of G distance from centreline of

front axle (unladen):4.4.4 C of G height above ground (combat laden):4.4.5 Lateral c of g distance from vehicle centreline

(left or right) as viewed from the rear (combatladen):

4.4.6 Longitudinal C of G distance from centreline offront axle (combat laden):

4.5 APPROACH AND DEPARTURE ANGLES4.5.1 Vehicle Approach Angle (GVM or combat laden

condition, at off-road tyre pressures, Figure 8):

4.5.2 Vehicle Departure Angle (GVM or combatladen condition, at off-road tyre pressures,Figure 8):

4.6 MISCELLANEOUS4.6.1 Eye height of average driver above ground:4.6.2 Maximum water fording depth:4.6.3 Vehicle fording speed:4.6.4 Vehicle projected frontal area:4.6.5 Overall vehicle width:4.6.6 Height of vehicle push bar above ground:4.6.7 Maximum force push bar can tolerate without

damage:4.6.8 Maximum braking coefficient (deceleration)

vehicle can develop (combat laden, eg 0.5g):4.6.9 Maximum Acceleration (GVM or Combat Laden

Condition):4.6.9.1 • Time from 0 to 40km/h4.6.9.2 • Time from 0 to 60km/h4.6.9.3 • Time from 0 to 80 km/h4.6.9.4 • Time from 0 to 100 km/h4.6.10 Is vehicle transportable by C130 aircraft

(yes/no)


C-5

5.0 DYNAMICS DATA5.1 Longitudinal distance of the driver from

vehicle’s first axle (+ve if forward, -ve if rear, fordrivers location use SAE J1163 Seat IndexPoint (SIP), or pivot centre between torso andthighs):

5.2 Height of driver’s seat (SIP) above ground:5.3 Pitch moments of inertia of sprung mass about

c of g (laden and unladen) units eg. kgm2 :5.4 Description of suspension systems for each

axle assembly (eg bogie, walking beam,independent, unsprung):

5.5 Unsprung mass at each wheel station (forbeam axle use half of each axle assemblymass):

5.6 Provide loading and unloading vertical force-deflection curve from full bump to full reboundtravel for each wheel station including theregions where stiffness increases when thesuspension limits are reached.

5.7 Length of bogie or beam arms if fitted (aseparate value for each wheel specifying thelongitudinal Distance from the wheel centre topoint of attachment to sprung mass):

5.8 Provide a bump and rebound damping force-velocity curve for each wheel station:

5.9 Rotational moment of inertia of each bogie orbeam arm:

5.10 Is a driver’s suspension seat fitted?5.11 Are suspension seats provided for other

occupants?5.12 If a suspension seat is fitted provide vertical

force-deflection curve from full bump to fullrebound travel including where stiffnessincreases when the suspension limits arereached:

5.13 If a suspension seat is fitted provide a bumpand rebound damping force-velocity curve:

6.0 HULL CLEARANCE DATA6.1 Provide data or scale drawing showing the vehicle hull profile in the unladen condition, referenced

to the first axle centreline (see Figure 9). Include hitch, differential and tailshaft(s) in profile.Include all lowermost foul points. Profile is at GVM at off-road tyre pressures.


C-6

7.0 Steering Data7.1 Maximum steer-angle of steering road wheels.7.2 Minimum kerb to kerb turning circle7.3 Provide the height and longitudinal position of

the centre of trailer attachment point (pintle,hitch, turntable etc.)

8.0 Fuel Consumption Data8.1 Provide the engine Specific Fuel Consumption

Performance Map providing mass flowrate offuel against engine speed for the full range ofspeed and net fly-wheel power (or torque).(Please state standard used, if net power ortorque is not available supply data on engineaccessory power consumption (Ref. example inFigure 10)

9.0 Tracked Vehicle Data9.1 Track Pitch (figure 11)9.2 Track width (figure 11)9.3 Does track have pads?

If so what is pad height (figure 11)9.4 Track Thickness (figure 11)9.5 Bogie or Road wheel rolling radius (figure 11)9.6 Number of teeth on drive sprocket.9.7 Number of road wheels on track assembly9.8 Is track rigid or flexible?9.9 Nominal static track tension (eg. kN)


C-7

9.10 Nominal track longitudinal stiffness(eg. kN/m)9.11 Sprocket – wheel - idler layout (ref. Fig 12)Note Measure from front sprocket or idler.9.11.1 x1, x2, x3, x4, etc. road wheel locations,

xa, distance to rear sprocket or idler(provide table withreference sketch)

9.11.2 Front sprocket or idler diameter (Df)9.11.3 Rear sprocket or idler diameter (Dr)9.11.4 Height of centre of front sprocket or idler above ground (Zf)9.11.5 Height of centre of rear sprocket or idler above ground

(Zr)


C-8

BLANK

DEF(AUST)8033 / Issue 2ANNEX D

D-1

ANNEX D

LEA-NRMM SCENARIO INFORMATION

Table D-1 - LEA Reference Terrain Data Sets to be Used forThe Determination of Mobility Categories

(MTDB files)Dry Season Wet Season

DAD DAWPCKDM PCKWMFERGRD FERGRW

PKTD PKTWBRADD BRADW

KATHSDD KATHSDW

Table D-2 - Scenario File Data to be Used forthe Determination of Mobility Categories

Scenario Variable Value (Dry Season) Value (Wet Season)ntyre 1 1cohes .5e-01 .5e-01

dclmax .5e+00 .5e+00gamma .2e+00 .2e+00iover 9 9iseasn 1 3isurf 1 1

isnow 0 0lac 1 1

map 74 74mnspd 0 0mapg 1 1month 7 12nopp 1 1nslip 0 0ntrav 3 3ntux 11 11phi .21e+02 .21e+02

react .5e+00 .5e+00rdfog .1e+04 .1e+04sftypc .9e+02 .9e+02vbrake .5e+01 .5e+01vismnv .2e+01 .2e+01

vlim 100.0 100.0zsnow .3e+01 .3e+01mtdb 1 1

DEF(AUST)8033 / Issue 2ANNEX D

D-2

BLANK

DEF(AUST)8033 / Issue 2ANNEX E

E-1

ANNEX E

AVERAGE ABSORBED POWER

INTRODUCTION

Average Absorbed Power (AAP) is the measure of the rate at which vibrational energy is absorbed by ahuman and is the quantity used to determine human tolerance to vibration when a vehicle is negotiatingrough terrain. It is calculated from the vertical acceleration time history at the driver’s seat. AAP isdefined here using Fortran code (power.f). It requires a 30 Hz Low Pass pre-filter (filter.f) Alternatively,AAP is defined in The Society of Automotive Engineers Technical Publication no. 680091 (AnalyticalAnalysis of Human Vibration, by Richard A. Lee and Fred Pradko, Mobility Systems Laboratory, USArmy Tank Automotive Command, Jan 1968).

FILTER.F

Input is a file called “ufaccel.dat”. This file contains a single column of sampled, unformattedacceleration data in g's, sampled at a constant rate.

Output is a file called “filtaccel.dat” and contains a single column of unformatted, filtered accelerationdata.

A variable, “frctof” is the filter cut-off frequency and is set to 30 Hertz in the code.

The variable “timeint” is the time interval in seconds of the sampling period used. In the code it is set to0.005 seconds. This should be altered before compilation if necessary.

POWER.F

Input is a file called “accelin.dat”. This file contains a single column of unformatted, sampled andfiltered acceleration data in g's.

Output is a file called “aapout.dat” and contains a single column of unformatted Average AbsorbedPower values in Watts.

The variable “dt” is the time interval in seconds of the sampling period used. In the code it is set to0.005 seconds. This should be altered before compilation if necessary.

program filter

c.....program to exercise low-pass filter

implicit none

real smplrt,frctof,f,xin,j,t,yout,timeint real vr,c,bb0,bb1,bb2,csq,bb1c,bb2c2,bb3c3,bb4c4,bcon,ai integer i

dimension f(5,4)


E-2

c.....xin are unfiltered accelerationsc.....yout are filtered accelerations

open(unit=1,file="ufaccel.dat") open(unit=2,file="filtaccel.dat")

c.....samplerate, number of samples per second timeint=0.005 smplrt=1/timeintc.....filter cut-off frequnecy, Hz frctof=30

call lpfset(smplrt,frctof,f)

c.....filter input signal.. output will lag input by 4 samples

1 read(1,*,end=99)xin j=f(5,4) t=xin*f(5,3) do 10 i = 1,4 t=t+f(j,1)*f(i,3)-f(j,2)*f(i,4) j=j+1 if(j.gt.5)j=110 continue yout=t write(2,*)yout f(j,2)=t f(j,1)=xin f(5,4)=j

goto 199 continue close(1) close(2) end

c.....c.....subroutine to setup for low-pass filter routinec..... subroutine lpfset(smplrt,frctof,f)cc.....4 pole butterworth low pass filter set-up routinec.....smplrt = no. data samples per sec.c.....frctof = cut-off freq. in hertzc.....f = work array of 20 elementsc dimension f(5,4) vr = frctof/(0.5*smplrt) c = 1.0/tan(vr*1.5707963)c.....4 pole butterworth analog transfer function bb0 = 1.0 bb1 = 2.6131259


E-3

bb2 = 3.4142136 csq=c*c bb1c=bb1*c bb2c2=bb2*csq bb3c3=bb1c*csq bb4c4=csq*csq bcon=2.*bb1c*(1.-csq) b4con=4.*bb4c4c.....digital filter function ai = 1./(bb0 + bb1c + bb2c2 + bb3c3 + bb4c4) f(1,3) = ai f(2,3) = 4.0*ai f(3,3) = 6.0*ai f(4,3) = f(2,3) f(5,3) = ai f(5,4) = 1. f(1,4) = (4.0 + bcon - b4con)*ai f(2,4) = (6.0 - 2.*bb2c2 + 6.*bb4c4)*ai f(3,4) = (4.0 - bcon - b4con)*ai f(4,4) = (1.0 - bb1c +bb2c2 - bb3c3 + bb4c4)*ai do 10 j=1,2 do 10 i=1,5 f(i,j)=0.10 continue return

endprogram power3

implicit none

real dt,fnew,fold,delf,pwrfk,pwrvar,u1,u2,u3,u4,u5,q3 real sumabp,a,b,c, avpwr,pout7 integer i,k,kuse dimension pwrfk(7),pwrvar(7),a(4),b(4),c(4),q3(7) common /rkgabc/ a(4),b(4),c(4) dt=0.005 call rkgset(dt) pout7=0

u1=0. u2=0. u3=0. u4=0. u5=0. pwrvar(1)=0. pwrvar(2)=0. pwrvar(3)=0. pwrvar(4)=0. pwrvar(5)=0. pwrvar(6)=0. pwrvar(7)=0.

open(unit=1,file="accelin.dat")c open(unit=2,file="apout.dat")


E-4

open(unit=3,file="aapout.dat")

c.... loop drops out when end of file readc.... maximum 1,000,000 samples

do i=1,1000000 fold=pout7 read(1,*,end=139)fnew pout7=fnew delf=(fnew-fold)*0.5c..... fnew=filtered driver instantaneous g'sc..... integrate power using rkg integration do 138 k=1,4 kuse=k go to (137,136,137,136),k136 fold=fold+delf137 call power(pwrfk(1),pwrvar(1),fold,u5) call rkg(pwrvar(1),pwrfk(1),q3(1),7,kuse)138 continuec..... u5=instantaneous absorbed power sumabp=sumabp+u5c write(2,*)u5 avpwr=sumabp*dt/(dt*i) write(3,*)avpwr enddo139 close(1)c close(2) close(3) end

c.....subroutine to exercize absorbed power equationsc.....input is filtered driver g's (drvinp)c.....output is instantaneous absorbed power in watts (u5)c..... subroutine power(fk,pwrvar,drvinp,u5) dimension fk(7),pwrvar(7) u1=-pwrvar(1) u2=-(u1+0.108*pwrvar(4)) u3=-(u2+0.250*pwrvar(6)) u4=-(u3+pwrvar(7)) u5=u4*u4 fk(1)=-(29.80*pwrvar(1)+15.45*drvinp*32.2+100.*pwrvar(2)) fk(2)=-10.*u1 fk(3)=-(736.9*u1+1000.*u2) fk(4)=-(100.*u1+35.19*pwrvar(3)+39.10*pwrvar(4)) fk(5)=-(1000.*u2+684.3*u3) fk(6)=-(80.*u2+30.28*pwrvar(5)+100.*pwrvar(6)) fk(7)=-(u3+6.*pwrvar(7)) return endc.....c.....subroutine to compute runge-kutta-gill 1/4 time-step


E-5

integration

subroutine rkg(x,fk,q,n,k)

real ta,tb,tc,p,x,fk integer i,k common /rkgabc/ a(4),b(4),c(4) dimension q(1),x(1),fk(1) save /rkgabc/

c begin

ta=a(k) tb=b(k) tc=c(k) do 10 i=1,n p=ta*(fk(i)-tb*q(i)) x(i)=x(i)+p q(i)=q(i)+3.*p-tc*fk(i)10 continue

return endc.....c.....subroutine to setup constants for runge-kutta-gill integrationc.....

subroutine rkgset(h)

real a,b,c,h,s2

common /rkgabc/ a(4),b(4),c(4) save /rkgabc/

c begin

s2=sqrt(2.) a(1)=h*0.5 a(2)=h/(2.+s2) a(3)=h*(1.+1./s2) a(4)=h/6. b(1)=2./h b(2)=1./h b(3)=b(2) b(4)=b(1) c(1)=a(1) c(2)=a(2) c(3)=a(3) c(4)=a(1) return end


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