drdo project work

8/13/2019 DRDO Project Work

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KARTIKA MOHANKARTIKA MOHAN

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Defence Research and Development Organisation

Emblem of DRDO

DRDO Bhawan, New Delhi, The Headquarters of DRDO

The Defence Research and Development Organisation(DRDO) is

an agencof de!elo"ment of technologfor use b the militar,

headquartered in New Delhi, #ndia$ #t was formed in %&' b the

merger of the Technical De!elo"ment Establishment and the

Directorate of Technical De!elo"ment and roduction with the Defence

*cience Organisation$

#t has a networ+ of ' laboratories which are engaged in de!elo"ingdefence technologies co!ering !arious fields, li+e aeronautics,

armaments, electronic and com"uter sciences, human resource

de!elo"ment, life sciences, materials, missiles, combat !ehicles

de!elo"ment and na!al research and de!elo"ment$ The organi-ation

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http://en.wikipedia.org/wiki/New_Delhihttp://en.wikipedia.org/wiki/Government_agencyhttp://en.wikipedia.org/wiki/Technologyhttp://en.wikipedia.org/wiki/Military_of_Indiahttp://en.wikipedia.org/wiki/New_Delhihttp://en.wikipedia.org/wiki/File:DRDO_Bhawan2.jpghttp://en.wikipedia.org/wiki/File:DRDO_Bhawan2.jpghttp://en.wikipedia.org/wiki/File:DRDO-logo.pnghttp://en.wikipedia.org/wiki/Government_agencyhttp://en.wikipedia.org/wiki/Technologyhttp://en.wikipedia.org/wiki/Military_of_Indiahttp://en.wikipedia.org/wiki/New_Delhihttp://en.wikipedia.org/wiki/New_Delhi


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includes more than ',... scientists and about ',... other scientific,

technical and su""orting "ersonnel$

Histor

%.'mm light field gun "rotot"e

Defence Research and De!elo"ment Organisation (DRDO) was

established in %&' b amalgamating the Defence *cience

Organisation and some of the technical de!elo"ment establishments$ /

se"arate De"artment of Defence Research and De!elo"ment was

formed in %&. which later on administered DRDO and its '.

laboratories0establishments$ 1ost of the time the Defence ResearchDe!elo"ment Organisation was treated as if it was a !endor and the

/rm Headquarters or the /ir Headquarters were the customers$ #f the

could get a 1i2 %from the world mar+et, the wanted a 1i2 % from

DRDO$345DRDO started its first ma6or "ro6ect in surface7to7air

missiles(*/1) +nown as ro6ect #ndigoin %&8.s$ #ndigo was

discontinued in later ears without achie!ing full success$ ro6ect

#ndigo led to ro6ect De!il, along with ro6ect 9aliant, to de!elo" short7

range */1 and #:B1in the %&;.s$ ro6ect De!il itself led to the later

de!elo"ment of the rith!imissile under the #ntegrated 2uided 1issileDe!elo"ment rogram(#21D) in the %&.s$ #21D was an

#ndian 1inistr of Defence"rogram between the earl %&.s and ..;

for the de!elo"ment of a com"rehensi!e range of missiles, including

the/gni missile, rith!i ballistic missile,/+ash missile, Trishul

missileand Nag 1issile$ #n .%., then defence minister/$


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De!elo"ment Organisation (DRDO) to gi!e =a ma6or boost to defence

research in the countr and to ensure effecti!e "artici"ation of the

"ri!ate sector in defence technolog=$

ro6ects

Aeronautics

The DRDO is res"onsible for the ongoing >ight :ombat /ircraft$ The

>:/ is intended to "ro!ide the #ndian /ir ?orcewith a modern, fl b

wire, multi7role fighter, as well as de!elo" the a!iation industr in #ndia$

The >:/ "rogram has allowed DRDO to "rogress substantiall in the

fields of a!ionics, flight control sstems, aircraft "ro"ulsion and

com"osite structures, along with aircraft design and de!elo"ment$

The DRDO "ro!ided +e a!ionics for the *u+hoi *u74.1 are also being fitted into

1alasian *u74.s$

The DRDO is "art of the #ndian /ir ?orce=s u"grade "rograms for

its 1i27;and *e"ecat Aaguarcombat aircraft, along with the

manufacturer Hindustan /eronautics >imited$ DRDO contributed

subsstems li+e the Tarang radar warning recei!er, Tem"est 6ammer,

core a!ionics com"uters, bra+e "arachutes, coc+"it instrumentation

and dis"las$

Avionics

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http://en.wikipedia.org/wiki/HAL_Tejashttp://en.wikipedia.org/wiki/Indian_Air_Forcehttp://en.wikipedia.org/wiki/Fly_by_wirehttp://en.wikipedia.org/wiki/Fly_by_wirehttp://en.wikipedia.org/wiki/Multi-role_fighterhttp://en.wikipedia.org/wiki/Sukhoi_Su-30MKIhttp://en.wikipedia.org/wiki/Su-30http://en.wikipedia.org/wiki/Indian_Air_Forcehttp://en.wikipedia.org/wiki/Indian_Air_Forcehttp://en.wikipedia.org/wiki/MiG-27http://en.wikipedia.org/wiki/Sepecat_Jaguarhttp://en.wikipedia.org/wiki/Hindustan_Aeronautics_Limitedhttp://en.wikipedia.org/wiki/File:DRDO_Bhawan.jpghttp://en.wikipedia.org/wiki/HAL_Tejashttp://en.wikipedia.org/wiki/Indian_Air_Forcehttp://en.wikipedia.org/wiki/Fly_by_wirehttp://en.wikipedia.org/wiki/Fly_by_wirehttp://en.wikipedia.org/wiki/Multi-role_fighterhttp://en.wikipedia.org/wiki/Sukhoi_Su-30MKIhttp://en.wikipedia.org/wiki/Su-30http://en.wikipedia.org/wiki/Indian_Air_Forcehttp://en.wikipedia.org/wiki/MiG-27http://en.wikipedia.org/wiki/Sepecat_Jaguarhttp://en.wikipedia.org/wiki/Hindustan_Aeronautics_Limited


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The DRDO=s a!ionics "rogram has been a success stor with its

mission com"uters, radar warning recei!ers, high accurac direction

finding "ods, airborne 6ammers and flight instrumentation in use across

a wide !ariet of #ndian /ir ?orce aircraft$ The organi-ation began

de!elo"ing these !arious items for its u"grades, and for the >:/"ro6ect$ 9ariants were then de!elo"ed for other aircraft$ The lead

designer in se!eral of these efforts has been D/RE, or the Defence

/!ionics Research Establishment, DRDO=s designated mission

a!ionics laborator$ Other laboratories ha!e also chi""ed in, from the

radar s"ecialist >RDE, to electronic warfare focused DE/> to the /DE,

which de!elo"s /9s and flight control sstems$

>:/ uses DRDO7

de!elo"ed a!ionics

The DRDO is also co7de!elo"ing more ad!anced a!ionics for the >ight

:ombat /ircraftand the #/?=s combat fleet$ These include a range of

"owerful O"en /rchitecture com"uters, better defensi!e a!ionics

including modern RCR=s, self7"rotection 6ammers, missile a""roach

warning sstems and integrated defensi!e suites, o"tronics sstems

and na!igational sstems such as Ring >aser 2ro based #nertial

na!igational sstems$

Unmanned aerial vehicles

The DRDO has also de!elo"ed two

unmanned aerial !ehicles7

the Nishant(Midnight) tactical /9

and the >a+sha(Target) ilotless

Target /ircraft (T/)$

The DRDO is also going ahead with its "lans to de!elo" a new class of

/9s$

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http://en.wikipedia.org/wiki/Light_Combat_Aircrafthttp://en.wikipedia.org/wiki/Light_Combat_Aircrafthttp://en.wikipedia.org/wiki/DRDO_Nishanthttp://en.wikipedia.org/wiki/Lakshya_PTAhttp://en.wikipedia.org/wiki/File:HAL_Tejas.jpghttp://en.wikipedia.org/wiki/Light_Combat_Aircrafthttp://en.wikipedia.org/wiki/Light_Combat_Aircrafthttp://en.wikipedia.org/wiki/DRDO_Nishanthttp://en.wikipedia.org/wiki/Lakshya_PTA


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Armaments

DRDO often coo"erates with the state owned Ordnance ?actories

Boardfor "roducing its items$ #t also hel"s #ndian /rmed forces b

manufacturing *mall /rms, 1issile "ro6ects and tactical roc+et sstem$

?or the #ndian /ir ?orce, DRDO has de!elo"ed Retarder Tail nits and

fu-e sstems for the '. +g bomb used b stri+e aircraft, 8 mm

@/rrow@ roc+ets (HE, ractice and HE/T) for roc+et "ods used in air to

ground and e!en air to air (if need be), a '. +g high s"eed low drag

(H*>D) bomb and "ractice bombs ?or the #ndian /ir ?orce, DRDO has

de!elo"ed Retarder Tail nits and fu-e sstems for the '. +g bomb

used b stri+e aircraft, 8 mm @/rrow@ roc+ets (HE, ractice and HE/T)

for roc+et "ods used in air to ground and e!en air to air (if need be), a

'. +g high s"eed low drag (H*>D) bomb and "ractice bombs$

DRDOLaboratories

Aeronautics%$ /DE $/DRDE 4$ :/B*$ :E1#>/:'$ D/RE

8$ 2TRE

Armaments %$ /RDE $ :?EE* 4$ HE1R> $ E '$ TBR>

Combat vehicles

and engineering%$ :9RDE $ #RDE 4$ RFDE */*E '$ 9RDE

Electronicsand computing

%$ DE*#DO: $/NR/2 4$ :/#R $ DE/> '$

D>R>

6. DTRL ;$ >/*TE: $ >RDE &$ 1TRD: %.$

*/2 %%$ **>

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Life sciences%$ D/R> $ DEBE>4$ D?R>$ D#R'$ D#/* 8$

DRDE ;$ DR>$ ?R> &$ #N1/*

aterials R!D %$ D>A $ D1R> 4$ D1*RDE

issiles %$ DRD> $ #**/ 4$ #TR $ R:#

"aval R!D %$ NO> $ N*T> 4$ N1R>

icro electronics

anddevices#ED$

%$ DE*#DO: $/NR/2 4$ 1TRD: $ **>

Others %$ D#/T $ #T1

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http://en.wikipedia.org/w/index.php?title=Defence_Agricultural_Research_Laboratory&action=edit&redlink=1http://en.wikipedia.org/wiki/Defence_Bioengineering_and_Electromedical_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Food_Research_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Institute_of_Psychological_Researchhttp://en.wikipedia.org/wiki/Defence_Institute_of_Physiology_and_Allied_Scienceshttp://en.wikipedia.org/wiki/Defence_Research_and_Development_Establishmenthttp://en.wikipedia.org/w/index.php?title=Defence_Research_Laboratory&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Field_Research_Laboratory&action=edit&redlink=1http://en.wikipedia.org/wiki/Institute_of_Nuclear_Medicine_%26_Allied_Scienceshttp://en.wikipedia.org/wiki/Materials_sciencehttp://en.wikipedia.org/wiki/Defence_Laboratory,_Jodhpurhttp://en.wikipedia.org/wiki/Defence_Metallurgical_Research_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Materials_and_Stores_Research_and_Development_Establishmenthttp://en.wikipedia.org/wiki/Missileshttp://en.wikipedia.org/w/index.php?title=DRDL&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Institute_for_System_Studies_and_Analyses&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Integrated_Test_Range&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Research_Centre_Imarat&action=edit&redlink=1http://en.wikipedia.org/wiki/R%26Dhttp://en.wikipedia.org/wiki/Naval_Physical_and_Oceanographic_Laboratoryhttp://en.wikipedia.org/wiki/Naval_Science_and_Technological_Laboratoryhttp://en.wikipedia.org/wiki/Naval_Materials_Research_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Scientific_Information_and_Documentation_Centrehttp://en.wikipedia.org/wiki/Advanced_Numerical_Research_and_Analysis_Grouphttp://en.wikipedia.org/wiki/Microwave_Tube_Research_and_Development_Centerhttp://en.wikipedia.org/wiki/Solid_State_Physics_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Institute_of_Advanced_Technologyhttp://en.wikipedia.org/w/index.php?title=Institute_of_Technology_Management&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Defence_Agricultural_Research_Laboratory&action=edit&redlink=1http://en.wikipedia.org/wiki/Defence_Bioengineering_and_Electromedical_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Food_Research_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Institute_of_Psychological_Researchhttp://en.wikipedia.org/wiki/Defence_Institute_of_Physiology_and_Allied_Scienceshttp://en.wikipedia.org/wiki/Defence_Research_and_Development_Establishmenthttp://en.wikipedia.org/w/index.php?title=Defence_Research_Laboratory&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Field_Research_Laboratory&action=edit&redlink=1http://en.wikipedia.org/wiki/Institute_of_Nuclear_Medicine_%26_Allied_Scienceshttp://en.wikipedia.org/wiki/Materials_sciencehttp://en.wikipedia.org/wiki/Defence_Laboratory,_Jodhpurhttp://en.wikipedia.org/wiki/Defence_Metallurgical_Research_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Materials_and_Stores_Research_and_Development_Establishmenthttp://en.wikipedia.org/wiki/Missileshttp://en.wikipedia.org/w/index.php?title=DRDL&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Institute_for_System_Studies_and_Analyses&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Integrated_Test_Range&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Research_Centre_Imarat&action=edit&redlink=1http://en.wikipedia.org/wiki/R%26Dhttp://en.wikipedia.org/wiki/Naval_Physical_and_Oceanographic_Laboratoryhttp://en.wikipedia.org/wiki/Naval_Science_and_Technological_Laboratoryhttp://en.wikipedia.org/wiki/Naval_Materials_Research_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Scientific_Information_and_Documentation_Centrehttp://en.wikipedia.org/wiki/Advanced_Numerical_Research_and_Analysis_Grouphttp://en.wikipedia.org/wiki/Microwave_Tube_Research_and_Development_Centerhttp://en.wikipedia.org/wiki/Solid_State_Physics_Laboratoryhttp://en.wikipedia.org/wiki/Defence_Institute_of_Advanced_Technologyhttp://en.wikipedia.org/w/index.php?title=Institute_of_Technology_Management&action=edit&redlink=1


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Defence Terrain Research Laborator%

Defence Terrain Research >aborator (DTR>) is a laboratot of the

Defence Research and De!elo"ment Organisation (DRDO)$ #t wasestablished in %&8 and is located in Delhi$ #ts "rimar function is

research and de!lo"ement of techniques to e!aluate terrains and

assess mobilit "otential of inaccessible areas$ The Defence Terrain

Research >aborator focuses on "ro!iding state7of7the7art terrain

intelligence to the armed forces$

&istor%

The DTR>=s origin dates bac+ to %&8 when a Terrain E!aluation :ell(TE:) was set u" as a unit of the DRDO$ The cell=s ob6ecti!es were tode!elo" techniques needed for e!aluating terrain and assessing themobilit "otential in inaccessible areas$ #t became a full7fledgedlaborator in %&%, and was renamed the Defence Terrain Research>aborator

Charter of duties

%$ To de!elo" a reliable sstem for "rediction of terrain characteristics

and deri!ation of militar "otential of !arious t"es of terrains basedon modern techniques of terrain e!aluation$

$ To de!elo" infrastructure, com"etence and instrumentation in thelatest techniques related to terrain research$

4$ To e!ol!e terrain data storage and retrie!al sstem for use bDefence *er!ices$

$ To interact with the *er!ices F other agencies including ni!ersitiesfor basic and a""lied as"ects of terrain research$

'$ To de!elo" methods for automatic feature eGtraction from remotelsensed data$

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8$ To "ro"agate the techniques of terrain e!aluation in Defence*er!ices and conduct training in this field$

Vision

To become a technological leader in "roducing high resolutionterrain intelligence "roducts for defence a""lications$

Mission

De!elo" eG"ertise and technologies for terrain databasemanagement$ :reate and u"date thematic ma"s and terrain

intelligence re"orts for the users$

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TRA''(CA)(L(T* ! CO+AR(,O" O' (L(TAR* -E&(CLE,.

2enerall s"ea+ing, trafficabilit is the ca"acit of soils to su""ort militar!ehicles$ The following "oints are to be +e"t in mind while e!aluating thetraffic abilit of militar !ehicles$

% O"erating and maintaining the soil7trafficabilit test set$ 1easuring trafficabilit with the results of the tests "erformed b the

cone "enetrometer and remolding equi"ment$4$ 1a+ing trafficabilit estimates from terrain data (to"ogra"h and soildata) and weather conditions$ Engineers must be cautious as thecalculated results can !ar b . or more from changes in tire "ressure

and deflection$

The trafficabilit of fine7grained soils (silts and clas) and sands thatcontain enough fine7grained material to beha!e li+e fine7grained soilswhen wet is more difficult to assess than trafficabilit in coarse7grainedsoils (clean sands)$ Relationshi"s that describe the soil7!ehicleinteractions are based on soil shearing7resistance measurements madewith the cone "enetrometer and corrected for soil remolding under!ehicle traffic b the remolding indeG (R#) "rocedures$

Toda most relations are used for one "ass and the combined effects on!ehicle "erformance of terrain features such as soil, !egetation, andslo"e can onl accuratel be determined through the use of thecom"uteri-ed /rm mobilit "rediction sstem contained in the N/TOReference 1obilit 1odel (NR11)$ The engineering relationshi"s which"roduce !ehicle s"eed "redictions or 2O0NO 2O "erformance based onmeasured terrain and !ehicle characteristics are contained in the NR11

)A,(C TRA''(CA)(L(T* 'ACTOR,

The following factors im"act soil trafficabilitI

,O(L ,TRE"T&

Bearing and traction ca"acities of soils are functions of their shearingresistance$ *hearing resistance is measured b the cone "enetrometerand is eG"ressed in terms of cone indeG (:#)$ Because the strength offine7grained soils (silts and clas) ma increase or decrease when loaded

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or disturbed, remolding tests are necessar to measure an loss of soilstrength eG"ected after traffic$ The fine7grained soil :# multi"lied b theR# "roduces the rating cone indeG (R:#) used to denote soil strengthcorrected for remolding$ / com"arison of the R:# with the !ehicle coneindeG (9:#) indicates whether the !ehicle can negotiate the gi!en soilcondition for a gi!en number of "asses$ ?or eGam"le, if a soil has a :# of%. and an R# of .$8. in its critical laer, the soil strength ma beeG"ected to fall to %. times .$8., or an R:# of ;, under traffic$Therefore, such soil is not trafficable for !ehicles with 9:# %is greater than;

,T(C/("E,,

*tic+iness ma seriousl ham"er !ehicles o"erating in wet, fine7grainedsoil$ nder eGtreme conditions, stic+ soil can accumulate in a !ehicle=srunning gears, ma+ing tra!el and steering difficult$

,L(++ER("E,,

EGcess water or a laer of soft, "lastic soil of low >> o!erling a firm laerof soil can "roduce a sli""er surface$ *uch a condition ma ma+esteering difficult or ma immobili-e rubber7tired !ehicles$ 9egetation,es"eciall when wet and on a slo"e, ma cause immobili-ation of rubber7tired !ehicles$

-AR(AT(O" O' TRA''(CA)(L(T* 0(T& 0EAT&ERCeather changes "roduce changes in soil trafficabilit$ ?ine7grained soilsincrease in moisture during rain "eriods$ This results in sli""eriness,stic+iness, and decreased strength$ Dr "eriods "roduce the o""ositeeffects$ >oose sands im"ro!e trafficabilit through an increase incohesion during rain "eriods and return to the loose, less trafficablestate during dr "eriods$ The absence of snow allows frost to "enetratemore dee"l into the soil$ Techniques ha!e been de!elo"ed for "redictingthe effects of weather on soil trafficabilit$ These techniques are "art of

the com"rehensi!e NR11 and are not included in this "ublication$

CR(T(CAL LA*ER

The critical laer is the laer in the soil that su""orts the weight of the!ehicle in question$ The critical laer=s de"th !aries with the soil t"e, thesoil=s strength "rofile, the !ehicle t"e and weight, and the number of

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"asses required$ Table ;7% summari-es these !ariations for commonmilitar !ehicles$

(",TRUE"T, A"D TE,T, 'OR TRA''(CA)(L(T*

Trafficabilit measurements are made with the soil7trafficabilit test set$This set consists of one can!as carring case, one cone "enetrometerwith 407inch steel and '07inch aluminum shafts and a .$'7square7inchcone, one soil sam"ler, remolding equi"ment (which includes a 407inchsteel shaft and a .$7square7inch cone, a '07inch steel shaft with footand handle, a J7"ound hammer, a clinder and base with "in), and a

bag of hand tools$ The items are shown in ?igure ;7% in their "ro"er"laces in the carring case$ The set is carried on the bac+ as shown in?igure ;7$ The com"lete set weighs %& "ounds$

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The "rimar instrument of the soil7trafficabilit test set is the cone"enetrometer$ #t is shown in ?igures ;74 and ;7 and ?igure ;7'$ #t isused to determine the shearing strength of low7strength soils$ There isalso a dnamic cone "enetrometer, but this instrument is used todetermine shear strength of high7strength soils such as those found in thebase courses of roads and airfields$

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The amount of force required to mo!e the cone slowl through a gi!en"lane is indicated on the dial inside the ring$ This force is an indeG of thesoil=s shearing resistance and is called the soil=s :# in that "lane$ Thedial=s range is . to 4.. "ounds "er square inch

EA,UR(" TRA''(CA)(L(T*

Chene!er reconnaissance "arties ha!e time to ta+e trafficabilitmeasurements, the should obtain data to determine the number andt"e of !ehicles that can cross the area and the slo"es the can climb$

RA"E O' CO"E ("DE1E,

/ :# ranging between %. and 4.. in the critical laer is required tosu""ort most militar !ehicles$ EGce"t for a few !ehicles, a :# below %. isconsidered to be a nontrafficable area and a :# abo!e 4.. is consideredtrafficable to all but a few !ehicles for '. "asses$ These limits usuallma+e it "ossible, while gathering data for trafficabilit e!aluation, to

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classif large areas as abo!e or below the critical range without eGtensi!etesting$

"U)ER O' EA,UREE"T,

The number of measurements ta+en is determined b the time a!ailable,the 6udgment of the range of soil strengths, and the general uniformit ofthe area$ Trafficabilit7measuring instruments are designed for ra"idobser!ations$ The accurac of the a!erage of an series of readingsincreases with the number ta+en$ 9ariations in soft soils require that atleast %' readings be ta+en to establish a true a!erage :# at an s"ot at agi!en de"th$ The %' readings should be distributed throughout a uniformarea$

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The numbers in the numerator are the indi!idual readings$ The number inthe denominator re"resents the number of tests conducted$ The resultingquotient is the a!erage :# for that de"th$

/fter all indi!idual readings are added together, the are a!eraged withthe reading abo!e and below to obtain the a!erage :# for that laer$ #nthe case of the .7 to 87inch laer, the 88 and ;% are added and thena!eraged (8)$ The 8 is the :# for the .7 to 87inch laer$ Readings arethen a!eraged for the 87 to %7inch laer and so on$

,TRE"T& +RO'(LE"ormal ,trength +rofile in 'ine2rained soils and Remouldable ,ands

#n a soil with a normal strength "rofile, the :# readings either increase orremain constant with each increment of de"th$ :#s should be measuredat 87inch increments down to % inches in the earl stages of areareconnaissance$ #f these measurements consistentl re!eal that the"rofile is normal, onl readings in the critical laer need to be recorded$

?or a trac+ed !ehicle weighing less than %..$... "ounds, such as the

1%%4/4 armored "ersonnel carrier (/:), readings are recorded for the87 and %7inch de"ths$

Abnormal ,trength +rofile in 'ine2rained ,oils and Remoldable ,ands

/n abnormal strength "rofile has at least one :# reading that is lowerthan the reading immediatel "receding it

Chen an abnormal strength "rofile eGists, :# readings should be madeand recorded at 87inch increments from the to" of the normal critical laer

(87inch de"th for the 1%%4/4 /:) to 8 inches below the bottom of thenormal critical laer (% inches for the 1%%4/4 /:)$

,trength +rofile in Coarse2rained ,oils

The critical laer for most !ehicles in coarse7grained soils is the .7 to 87inch laer$ 1ost coarse7grained soils ha!e a normal strength "rofile with

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a large increase in strength with de"th when com"ared to fine7grainedsoils$ ?or this reason, :# measurements should be ta+en at 47inchincrements to % inches or until the maGimum ca"acit (4.. :#) of the"enetrometer has been reached$

RAT(" CO"E ("DE1

The R:# is the :# that will result under traffic$ This !alue is com"ared tothe 9:# to determine the trafficabilit of the area for a s"ecific !ehicle$

To estimate how man !ehicles will cross an area when the R:# is lessthan the 9:#'.or to see what the 9:# for less than '. !ehicles will be,use the following formulaI

9:#'.7 9:#%K 9:#

will gi!e an increment for one !ehicle that, when added to the willgi!e the 9:# for an amount of !ehicles u" to '.$

OT&ER TRA''(CA)(L(T* E-ALUAT(O" 'ACTOR,

#n addition to the :# of an area, consider the factors that follow whene!aluating trafficabilit$

,lope

The stee"est slo"e, or ruling grade, that must be negotiated should bedetermined b studing a contour ma"$ ?or tra!el o!er slo"es, the :#requirements must be increased o!er those required for le!el terrain$

,tic3iness

*tic+iness occurs in all fine7grained soils when the are wet$ The greaterthe "lasticit of the soil, the more se!ere the effects of stic+iness$*tic+iness ad!ersel affects the s"eed and control of all !ehicles but will

not cause immobili-ation eGce"t for the smallest trac+ed !ehicles$

,lipperiness

>i+e stic+iness, the effects of sli""eriness cannot be measured$ *oils thatare co!ered with water or a laer of soft, "lastic soil usuall are sli""erand often cause steering difficult, es"eciall in rubber7tired !ehicles$

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#mmobili-ation can occur when sli""eriness is associated with low7bearing ca"acit$

-egetation

The effects of !egetation on trafficabilit are not within the sco"e of thismanual, but some "oints are worth of mention$ Dense grass, es"eciallif wet, ma "ro!ide sli""er conditions$

Organic2,oil Areas

1uch of the terrain in northern latitudes is blan+eted with a laer oforganic material com"osed of roots, mosses, and other !egetation in

!arious stages of decom"osition$ >imited testing with militar !ehiclesre!eals that low7ground7"ressure, trac+ed !ehicles, such as the 1&;4small7unit su""ort !ehicle (**9), can tra!el '. "asses o!er organicmats that are more than 8 inches thic+$

Other Obstacles

/ com"lete assessment of the traffic abilit of a gi!en area must includean e!aluation of obstacles such as forests, ri!ers, boulder fields, ditches,and hedgerows$ EGact effects of such obstacles on the "erformance of!ehicles are determined b the com"rehensi!e NR11 but are not withinthe sco"e of this manual$

,EL'2+RO+ELLED4 TRAC/ED -E&(CLE, A"D ALL20&EEL2DR(-E-E&(CLE, "EOT(AT(" ,LO+E,

The maGimum slo"e negotiable and the maGimum towing force or gross!ehicle weight for the R:# are essentiall equal$ Therefore, when the R:#is +nown, the maGimum slo"e negotiable b a gi!en !ehicle for '. "asses(or b '. similar !ehicles in straight7line formation) can be estimated from

?igure ;7;$

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sing ?igure ;7;, the maGimum slo"e equals '. "ercent$ The maGimumslo"e the 1%/% can negotiate under the gi!en conditions is '. "ercent$

,elf2+ropelled4 Trac3ed -ehicles and All20heel2Drive -ehicles Up ,lopes

The maGimum slo"e negotiable and the maGimum towing force (as a

"ercentage of gross !ehicle weight) for the same R:#G are essentiallequal$ Therefore, when the R:# is +nown, the maGimum slo"e negotiableb a gi!en !ehicle for one "ass in a straight line u" a slo"e can bedetermined b using the information in ?igure ;7$

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sing ?igure ;7, at R:#GK 8., the maGimum slo"e K 84 "ercent$ nder

the stated conditions, the maGimum slo"e the 1%/l tan+ can negotiate is84 "ercent$

#n ?igure ;7, at R:#GK ;, the maGimum slo"e K % "ercent$ nder thestated conditions, the 1&4 truc+ can climb a slo"e less than or equal to% "ercent$

+ER'ORA"CE CATEOR(E,

1ilitar !ehicles can be di!ided into se!en arbitrar categories according

to the minimum :# requirements (9:#%and 9:#'.)$ The range of 9:#%sand 9:#'.s for each categor (eGce"tions are numerous) are shown inTable ;74$

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TRAC/ED -E&(CLE, O" LE-EL TERRA("

/s a general rule, trac+ed !ehicles are able to tra!el on all le!el, coarse7

grained soils regardless of soil strength$ erformance "redictions in theNR11 are made for two categories of trac+ed !ehiclesL fleGible, found onmost militar !ehicles, or girderi-ed, found on most bulldo-er7t"e!ehicles$

CALCULAT(O", O' -E&(CLE CO"E ("DE1

:alculation of a coarse7grained 9:# for a !ehicle configuration isconsidered beond the sco"e of this manual$ These "redictions are madeusing the com"rehensi!e NR11$ #n general, wheeled !ehicles o"erating

in sands should use the lowest tire "ressures "ossible and all7wheel7dri!efor maGimum off7road "erformance$

TRA''(CA)(L(T* DATA

The ob6ecti!e of ma""ing trafficabilit data is to "ro!ide commandingofficers with an estimate of an area=s trafficabilit "rior to actual o"eration$The estimate consists of "lacing smbols that describe the trafficabilit of

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a small area at strategic "oints on eGisting ma"s as shown in ?igure ;7%$The ma"s "roduced b the techniques described in the following"aragra"hs are elementar com"ared with the com"licated andcom"rehensi!e ma"s now in "roduction for use with the NR11$

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E,T(AT("

Trafficabilit can be estimated if weather conditions, soils, and areato"ogra"h are generall +nown$ Ceather and climatic informationusuall are a!ailable, e!en for remote areas, from meteorological

records, climatolog teGtboo+s, or "ersonnel interrogation

0eather Conditions

?or estimating trafficabilit, consider onl two general weatherconditions77the @dr season@ and the @wet season$@

Dr% ,eason$ / dr season is defined as a time when climatic and!egetation factors combine to "roduce, in general, low soil moistures$During the dr season, fine7grained soils and remoldable sands of an

t"e usuall are trafficable and, in general, are of higher trafficabilit thandr, coarse7grained soils

0et ,eason$ / wet season is defined as a time in which weatherconditions combine to "roduce high soil moistures$ /dding moisture to asoil affects the strength of that soilL the effect differs with soil t"es$

TRA''(CA)(L(T* A+,

/ wide !ariet of mobilit7related "roducts can be obtained from

com"uteri-ed mobilit models such as the NR11 or :/11*$ #n"utterrain data includes land useI terrain slo"eL obstaclesL soil t"esL!egetation t"e, densit, and s"acingL surface geometrL linear andhdrologic feature dataL and road and trail data$ This data is used b themodels with in"ut !ehicle data to ma+e s"eed or 2O0NO 2O "redictionsfor each indi!idual terrain unit (on a quad sheet) formed b the com"leGinter"la of the in"ut !ariables$

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?igure ;7%is a dis"la of "otential landing -ones from :/11* for the

same areas as in ?igure ;7%4$ The "otential landing7-one ma" indicates"rimaril unfa!orable landing7-one sites, with fa!orable sites located inthe northwest third and southeast corner of the quad$ This dis"la hel"sguide the user to the most suitable sites for landing7-one construction$

?igure ;7%', is a dis"la of *:* soil7t"e descri"tions from :/11* forthe same area as in ?igures ;7%4 and ;7%$ This dis"la indicates thelocalit of soil t"es that ma be useful in scouting for constructionmaterials or sites more suitable for road and airfield construction$

A"UALL* A++(" ,O(L CO"D(T(O", A"D TRA''(CA)(L(T*

/lthough ma""ing soil conditions and trafficabilit through manual meansis rarel done since the de!elo"ment of com"uteri-ed mobilit models, itis im"ortant that the "rocedure be "resented should the need e!er arise$

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The tan+s can negotiate the 4.7"ercent slo"e in single file (a!ailable R:#of . is greater than the required R:# of 84)$ /ll truc+s cannot negotiatethe slo"e in single file (a!ailable R:# of . is less than the required R:#of ), but the can fan out and negotiate the slo"e on a one7"ass basis(a!ailable R:# of . is greater than the required R:# of %)$ Theconclusion is that all !ehicles could tra!el from to M through areas %, ',and 8, res"ecti!el, "ro!ided caution is used with the truc+s$ This route isshown as a dashed line$

This eGam"le indicates the usefulness of ma""ed trafficabilit data in"lanning o"erational eGercises$

,O(L2TRA''(CA)(L(T* CLA,,('(CAT(O"

*oil classification of a s"ecific area can be accom"lished ra"idl for

seasonal (high7moisture) conditions when the soil has been classified interms of the *:*, the to"ogra"h (high or low) has been identified, andthe 9:# for !ehicle categor has been determined $

'("E2RA("ED ,O(L,

The trafficabilit classification of fine7grained soils is shown in Table ;7$

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9ehicles with a 9:#'.or 9:#%equal to or greater than will ha!e a less than '. "ercent"robabilit of tra!ersing the area$

9ehicles with a 9:#'.or 9:#%equal to or greater than '8, but less than , will ha!e a"robabilit equal to or greater than '. "ercent, but less than ' "ercent, of tra!ersing the area$

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9ehicles with a 9:#'.or 9:#%equal to or greater than %, but less than '8, will ha!e a"robabilit equal to or greater than ;' "ercent, but less than &. "ercent, of tra!ersing the area$

9ehicles with a or 9:#'.or 9:#%less than % will ha!e a "robabilit equal to or greater than &."ercent, but no more than %.. "ercent, of tra!ersing the area$

COAR,E2RA("ED ,O(L,

The trafficabilit classification of coarse7grained soils can be obtainedfrom ?igure ;7%8$ The classification inter"retation is the same as for thetrafficabilit of fine7grained soils from Table ;7$ To use ?igure ;7%8,identif onl the coarse7grained soils (location and origin) and determinethe 9:#s from the equation "resented earlier in this cha"ter$ ?igure ;7%8a""lies to wheeled !ehicles onl$ The effect of the strength of coarse7grained soils on trac+ed7!ehicle "erformance is negligible$

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T&EOR* O' ROU"D -E&(CLE,

echanics of -ehicle 5 Terrain interaction

Terramechanics

(ntroduction

Chile trans"orting "assengers and goods b !ehicles on "a!ed roadsconstitutes a significant "art of the o!erall trans"ortation acti!ities in amodem societ, a wide range of human endea!ors in such fields asagriculture, logging, construction, mining, eG"loration, recreation, and

militar o"erations still in!ol!es locomotion o!er un"re"ared terrainusing s"eciali-ed off7road !ehicles$ *stematic studies of the "rinci"lesunderling the rational de!elo"ment and design of off7road !ehicles,therefore, ha!e attracted considerable interest, "articularl since CorldCar ##$

%$ The stud of the "erformance of an off7road !ehicle in relationto its o"erating en!ironment (the terrain) has now become +nown as@terramechanics@

$ #n off7road o"erations, !arious t"es of terrain with differingbeha!ior, ranging from desert sand through soft mud to fresh snow,ma be encountered$ The "ro"erties of the terrain quite often im"osese!ere limitations to the mobilit of off7road !ehicles$ /n adequate+nowledge of the mechanical "ro"erties of the terrain and its res"onseto !ehicular loading7terramechanicsis, therefore, essential to the"ro"er de!elo"ment and design of off7road !ehicles for a gi!enmission and en!ironment$

4$ On a gi!en terrain, the "erformance of an off7road !ehicle is,to a great eGtent, de"endent u"on the manner in which the !ehicleinteracts with the terrain$ :onsequentl, an understanding of themechanics of !ehicle7terrain interaction is of im"ortance to the "ro"erselection of !ehicle configuration and design "arameters to meets"ecific o"erational requirements$ / central issue in terramechanics is

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to establish a quantitati!e relationshi" between the "erformance anddesign of an off7road !ehicle for a gi!en o"erating en!ironment$ O!erthe ears, a !ariet of methods, ranging from em"irical to theoretical,for "redicting the "erformance of trac+ed and wheeled !ehicles o!erun"re"ared terrain ha!e been de!elo"ed or "ro"osed$

D(,TR()UT(O" O' ,TRE,,E, (" T&E TERRA(" U"DER-E&(CULAR LOAD,

:ertain t"es of terrain, such as saturated cla and com"act sand,which co!er "art of the trafficable earth surface, ma be com"ared toan ideal elasto"lastic material with the stress7strain relationshi" shownin I

or

Chen the stress le!el in the terrain does not eGceed a certain limit,such as that denoted b "a", the terrain ma eGhibit elastic beha!ior$The ideali-ation of the terrain as an elastic medium has found

a""lications in the "rediction of stress distribution in the soil, inconnection with the stud of soil com"action due to !ehicular loads

The "rediction of stress distribution in an elastic medium sub6ect to ans"ecific load ma be based on the analsis of the distribution of stressesunder a "oint load$ The method for calculating the stress distribution in asemi7infinite, homogeneous, isotro"ic, elastic medium sub6ect to a !ertical

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The "oints in the medium that eG"erience the same le!el of stress form afamil of isostress surfaces commonl +nown as "ressure bulbs$ Thegeneralcharacteristics of the bulbs of !ertical "ressure under a uniformstri" load are illustrated$

Fig. 2.4Distribution of vertical stresses in a semi-infinite elastic medium under a tracked

vehicle

There is a tendenc for the com"ressi!e stress in the soil to concentratearound the loading aGis$ This tendenc becomes greater when the soilbecomes more "lastic due to increased moisture content or when the soilis less cohesi!e, such as sand$ #n !iew of this, !arious semi7em"iricalequations ha!e been de!elo"ed to account for the different beha!ior of!arious t"es of soil$ ?rohlich introduced a concentration factor v toBoussinesq=s equations$

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The factor ! reflects the beha!ior of !arious t"es of soil in differentconditions$ #ntroducing the concentration factor, the eG"ressions for the!ertical and radial stress in the soil sub6ect to a "oint load on the surfaceta+e the following formsI

The !alue of the concentration factor de"ends on the t"e of soil and itsmoisture content

/ tire transfers its load to the soil surface usuall not at one "oint, but

through a finite area of contact$ To determine the stress distribution in thesoil due to tire loading, the actual si-e of the contact area and the"ressure distribution o!er the contact "atch must be +nown$ ?igure $;shows the measured contact areas of a tire under different soil conditions[2.5]. The rut becomes dee"er with increasing "orosit and moisturecontent of the soil$ /n a""roGimatel uniform "ressure o!er the entirecontact area ma be assumed for tires without lugs in hard, dr soil$ #n softsoils, the "ressure o!er the contact area !aries with the de"th of the rut$suall, the contact "ressure decreases towards the outside of the

contact area, and is more concentrated towards the center of the loadingarea$ Re"resentati!e "ressure distributions o!er the contact area in hard,dr soil, in fairl moist, relati!el dense soil, and in wet soil are shown in?ig$ $(a), (b), and (c), res"ecti!el

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remains the same$ This indicates that the stress distribution in a soil is afunction of not onl contact "ressure, but ,also contact area$

A++L(CAT(O", O' T&E T&EOR* O' +LA,T(C E7U(L()R(U TO T&EEC&A"(C, O' -E&(CLE2TERRA(" ("TERACT(O"

Chen the !ehicular load a""lied to the terrain surface eGceeds a certainlimit, the stress le!el within a certain boundar of the terrain ma reachthat denoted b @a@ on the ideali-ed stress7strain cur!e shown in ?ig$ $%$

/n infinitel small increase of stress beond "oint @a;= "roduces a ra"idincrease of strain, which constitutes "lastic flow$ The state that "recedes

"lastic flow is usuall referred to as "lastic equilibrium$ The transition fromthe state of "lastic equilibrium to that of "lastic flow re"resents the failureof the mass$

There are a number of criteria "ro"osed for the failure of soils and othersimilar materials$ One of the widel used and the sim"lest criterion is thatdue to 1ohr7:oulomb$ #t "ostulates that the material at a "oint will fail ifthe shear stress at that "oint in the medium satisfies the followingconditionI

where r is the shear strength of the material, c is the a""arent cohesion ofthe material, a is the normal stress on the sheared surface, and C8 is theangle of internal shearing resistance of the material$

:ohesion of the material is the bond that cements "articles togetherirres"ecti!e of the normal "ressure eGerted b one "article u"on the other$On the other hand, "articles of frictional masses can be held together onlwhen a normal "ressure eGists between them$ Thus, theoreticall, theshear strength of saturated cla and the li+e does not de"end on the

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normal load, whereas the shear strength of dr sand increases with anincrease of the normal load$

?or dr sand, therefore, the shear strength ma be eG"ressed b

and for saturated cla and the li+e, it ma ta+e the form

2ranular masses that co!er most of the trafficable earth surface, howe!er,

usuall ha!e both cohesi!e and frictional "ro"erties$ The meaning of the1ohr7:oulomb criterion ma be illustrated with the aid of the 1ohr circleof stress$ #f s"ecimens of a soil are sub6ect to different states of stress, foreach mode of failure a 1ohr circle can be constructed#f a straight lineen!elo"e is drawn to the set of 1ohr circles so obtained, it will be of theform of Eq$ $%., with the cohesion of the soil being determined b theinterce"t of the en!elo"e with the shear stress aGis, and the angle ofinternal shearing resistance being re"resented b its slo"e$ The 1ohr7:oulomb criterion is sim"l that if a 1ohr circle re"resenting the state of

stress at a "oint in the soil touches the en!elo"e, failure will ta+e "lace atthat "oint$

E+(R(CAL ET&OD, 'OR +RED(CT(" O''2ROAD -E&(CLE+ER'ORA"CE

The general a""roach to the de!elo"ment of em"irical methods for"redicting off7road !ehicle "erformance is to conduct tests of a selectgrou" of !ehicles considered to be re"resentati!e o!er a range of terrains

of interest$ The terrain is identified (or classified) b sim"le measurementsor field obser!ations$ The results of !ehicle "erformance testing and theterrain characteristics identified are then em"iricall correlated$ This canlead to the de!elo"ment of em"irical relationshi"s for e!aluating terraintrafficabilit on the one hand, and !ehicle mobilit on the other$

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Empirical ethods )ased on the Cone (nde9

These methods were originall de!elo"ed during Corld Car #% b the $*$/rm Caterwas EG"eriment *tation (CE*) to "ro!ide militar intelligenceand reconnaissance "ersonnel with a sim"le means to assess !ehiclemobilit on a @golno go@ basis in fine7 and coarse7grained soils$ ?ine7grained soils are silt or clae soils for which '. or more b weight ofthe grains being smaller than .$.; mm in diameter (or "assing through aNo$ .. sie!e)$ :oarse7grained soils are beach and desert soils, usuallcontaining less than ; of the grains smaller than .$.; mm in diameter,or soils containing ; or more of the grains smaller than .$.; mm indiameter but not in a wet condition, that is, the are nonremoldable$ Theform the basis for the subsequent de!elo"ments of the N/TO Reference1obilit 1odel (NR11)$

The basic com"onent of a cone "enetrometer

Cith recent ad!ances in electronics and com"uter technolog, a !arietof cone "enetrometers using electronic (or electrical) sensors formonitoring the force and "enetration de"th, as well as com"utertechnolog for storing and "rocessing measured data, ha!e beende!elo"ed$

Empirical Method for Predicting Tracked Vehicle Performance:

#n the method de!elo"ed b CE* for "redicting trac+ed !ehicle"erformance, an em"irical equation is first used to calculate the mobilitindeG (1#) of a gi!en !ehicle$

Based on the mobilit indeG (1#), a "arameter called the !ehicle coneindeG (9:#) is calculated$ The 9:# re"resents the minimum strength of a

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soil in the critical laer that "ermits a gi!en !ehicle to successfull ma+e as"ecific number of "asses, usuall one "ass or '. "asses$

/fter the 9:# and soil strength ha!e been determined, the !alues of the"erformance "arameters of a trac+ed !ehicle, such as the net maGimumdrawbar "ull coefficient (the ratio of drawbar "ull to !ehicle weight),maGimum slo"e negotiable, and towed motion resistance coefficient (theratio of towed motion resistance to !ehicle weight), are then em"iricalldetermined as functions of !ehicle t"e, number of "asses to becom"leted, and the eGcess of R:# o!er 9:# (i$e$, R:#79:#) for fine7grainedsoils or :# for coarse7grained soils$

Empirical Methods for Predicting Wheeled Vehicle Performance I

*imilar to the em"irical method for "redicting trac+ed !ehicle "erformancedescribed abo!e, in this method de!elo"ed b CE*, an em"iricalequation is used to calculate the mobilit indeG of an off7road wheeled!ehicle$

The em"irical relations for "redicting tire "erformance based on soil7tirenumerics, "articularl the sand7tire numeric, ha!e undergone a number ofre!isions since the were first "ro"osed as new eG"erimental dataemerged

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Empirical ethods )ased on the ean a9imum +ressure

/nother em"irical method for e!aluating the mobilit of off7road !ehicles isbased on the conce"t of mean maGimum "ressure (11) "ro"osed bRowland, which is defined as the mean !alue of the maGima occurringunder all of the roadwheel stations$ Em"irical equations for "redicting the!alues of 11 of trac+ sstems with different design features are gi!enbelow$

EA,UREE"T A"D C&ARACTER(:AT(O" O' TERRA("RE,+O",E

Owing to the limitations of the theories of elasticit and "lastic equilibrium,as well as the em"irical methods described abo!e, methods for "arametricanalsis of off7road !ehicle "erformance based on the measurement ofterrain res"onse under loading conditions similar to those eGerted b anoff7road !ehicle and on a detailed analsis of the mechanics of !ehicle7terrain interaction ha!e been de!elo"ed$

One of the well7+nown techniques for measuring the res"onse of terrainto loading "ertinent to !ehicle mobilit studies is that "ro"osed b Be++er$This technique has now become +nown as the be!ameter technique$ #tcom"rises two basic sets of testsI one is a set of "late "enetration tests,and the other is a set of shear tests$ #n the "enetration test, a "late of

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suitable si-e is used to simulate the contact area of the !ehicle runninggear, and the "ressure7sin+age relationshi" of the terrain is measured

A sim"lified model for "redicting trac+ed !ehicle "erformance

The basic features of a be!ameter designed to carr out the testsdescribed abo!e are illustrated$ / hdraulic ram is usuall used to a""lnormal load to the sin+age "late in the "ressure7sin+age test$ lates ofcircular sha"e are commonl used$ The a""lied "ressure and the resultingsin+age of the "late are recorded as shown$ #n shear tests, a shear ring isusuall em"loed to a""l shear loading to the terrain surface under!arious normal "ressures$ The torque a""lied and the resulting angulardis"lacement of the shear ring are recorded, as shown, from which theshear stress7shear dis"lacement relationshi" and the shear strength"arameters of the terrain can be deri!ed$ To "redict the traction de!elo"ed

b a rubber tire or b a rubber trac+, the characteristics of rubber7terrainshearing should be measured$ These can be obtained using a shear ringco!ered with a laer of rubber of the same com"osition as that for the tiretread or the trac+$

*chematic !iew of a be!ameter for measuring terrain "ro"erties$

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/ !ehicle7mounted$ be!ameter in field o"eration

Organic Terrain (Muskeg

?or a commonl encountered organic terrain (mus+eg), there is a mat ofli!ing !egetation on the surface with a laer of saturated "eat beneath it$ /re"resentati!e "ressure7sin+age cur!e for the organic terrain obtained inthe field is shown$

ressure7sin+age relationshi" for an organic terrain (mus+eg)$

#t can be seen that, initiall, the "ressure increases with an increaseinsin+age$ Howe!er, when the a""lied "ressure (or load) reaches a certain

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"enetrometer$ /fter that we can find out how man !ehicles cannegotiate this terrain$ *o we measure onl the @soil factor@$ On the otherhand there is a method described in the field manual @lanning andDesign of Roads, /irfields, and Heli"orts in the Theater of O"erations Road Design@, where it is +nown the number of !ehicles and it is wantedto learn if the can go through the area or not$ *o in this sstem we ta+ewith account two factors 7 @soil factor@ and @!ehicle factor$

; ; ; ; ; ; ; ; ;

drdo project work

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