vehiclebodyengineeringbyvs-160120145611-converted.pptx

VEHICLEBODYENGINEERING
Complied & Edited by Velmurugan Sivaraman
1/20/2016
1

T
e
r
m
susedtodescribeearlyvehiclebodystyles
2
Berlina RarelyusedbeforetheFirstWorld War
.A closed
luxury car with small windows which allowed the
occupantstoseewithoutbeing seen.
Cab A term tak
en directly from the daysof the horse-
drawn carriages. Used to describe an enclosed vehicle
which carried two passengers, while the driver w
a
s
situatedinfrontofthiscompartmentandunprotected.
Cabriolet Used tow
a
rds the end of the period.
Describesacarwithacollapsiblehoodandseating two
orfourpeople.
Coupé A vehicle divided by a fixed or movable glass
partition, behind the front seat. The driver’s position
w
a
sonly partially protected by the roof whilstthe rear
compartmentw
a
stotallyenclosedandveryluxurious.
Compiled & Edited ByVelmuruganSivaraman 1/ 20/ 2016

T
e
r
m
3
Coupé cabriolet or double cabriolet A long
vehicle having the front part designed as a
coupéandtherearpartdesignedasa cabriolet.
Therewereoftentwosupplementary seats.
Coupé chauffeur A coupé with the driving
position completely covered by an extension of
therearroof.
Coupé de ville A coupé having the driving
positioncompletely open.
Coupé limousine A vehicle having a totally
enclosed rear compartment and the front
drivingpositionclosedonthesidesonly
.

T
e
r
m
4
Double Berlina AlongerversionoftheBerlina but
havingthedrivingpositionseparatedfromthe
rearpartofthevehicle.
Double landaulet Alongerversionof thelandaulet. It
had twopermanentsea
tsplustwooccasional sea
ts
intherearandadriving positioninfront.
Double phaeton A phaeton which had two double
sea
tsincludingthedriver’sseat.
Double tunneau A longer version of the tonneau in
which the front sea
ts were completely separated
fromtherearseats.
Landau Acabrioletlimousinehavingonlytheroof
behindtherearwindowscollapsible.

T
e
r
m
5
Landaulet or landaulette Asmalllandauhaving
onlytwosea
tsintheclosedcollapsibleroof
portion.
Limousine Alongerversionof thecoupéwith
doublesidewindowsintherear compartment.
Limousine chauffeur A limous
ine with
an extendedrearrooftocoverthe
driving position
Phaeton A term from the days of the horse-
drawn carriage. In early motoring it w
a
s used to
describe a lightweight car with large spoked
wheels,onedoubleseatandusuallyahood.
Runabout Anopensportingtypeofvehiclewith
simplebodyworkandtwosea
tsonly
.

T
e
r
m
6
TonneauAnopenvehiclehavingafrontbenchseatanda
semi-circularrearseatwhichw
a
sbuiltintothereardoors.
Glasssaloon Alargeclosedvehiclesimilartoadouble Berlina
butwithenlargedwindows.
SaloonAvehiclehavingthedrivingseatinsidetheenclosed
carbutnotseparatedfromtherearseatbyapartition.
TorpedoAlongsportsvehiclehavingitshoodattachedto
thewindscreen.
Victoria Anothertermderivedfromtheeraofhorses.The
Victoriaw
a
salong,luxuriousvehiclewithaseparatedriving
positionandalargerearseat.Itw
a
sequippedwithhoods
andsidescreens.
Wagon saloon Aparticularlyluxurioussaloonusedfor
officialpurposes.

Basic Feature of an Automobile
7

• Progressofcivilizationisintimatelyconnectedwiththemeansoftransportation
• Aself-propelledvehicleusedfortransportationofgoods&passengersonlandis
calledAutomobileorAutomotive/ MotorV
ehic
le
• Anautomobileiscomprisedofac
hassis&body
• Chassisismadeupofaframesupporting;body/ powerunit/ transmissionsystem
/ controlsystem
• Ac
hassisframeissupportedbywheels&tyresthroughsuspensionsystemand axles
• Thepowerdeliveredbypowerunit(engine)istransmittedthroughclutchorfluid
coupling,transmissionsystem,andaxletothewheels
8

• Automobile ispropelled on roadduetofrictionbetweenthetireandroadsurface
• V
arioussub- systemsoftheautomobileareproperlydesigned&heldtogetherfor
efficientfunctioningindividually&a
swella
swholeunit.
• Thebodyandsuspensionprovidesprotection&comfort
• Automobilehasitslimitationsinregardtoload,speed&distanceitcantravel
9

10

11

General Classification of Automobiles
12

13

14

15
Automobilescanbeclassifiedfromvariouspointofviewofconsiderations like;
Use
Capac
it
y Make
Model
Fuel
Wheels
Drive
T
ransmission
:Motorcycle,car
,Bus,…
:L
C
V
,M&HCV
,…
:AshokLeyland,Maruti,Hyundai,T
a
ta
,Honda,Bajaj,…
: Zen,..
:Petrol,Diesel,CNG, …
:T
w
o
,three,four
,...
:Lefthanddrive,Righthanddrive,Frontwheeldrive,...
:Conventional(Manual),Automatic…

16
Construction :
 Unitizedbodyconstruction
 V
ariousbodysectionsareuseda
sstructuralstrengthmembertohelpsupport
&stiffentheentireunit
 Allsectionsareweldedtogethertoformanunit.
 thiseliminatestheneedofheavyc
hassisframe
 SeparateBody&Chassisconstruction
 Theframeisconstructeda
saseparateunitandbodyisboltedtoitatvarious
points
 Theframemustbequiterigid,sincethesuspensionsystem,engineandbody
dependsupontheframetosupportandk
eepallunitsin alignment

1/ 20/ 2016
Compiled•&
17
T
ypesof V
ehicle :
• Single-unitV
ehic
lesorloadcarriers
• Conventionalfourwheeltypeswithtwoaxledesign
• Frontaxleisasteeringnon-drivingaxle
• Rearaxleisdrivingaxle
• ArticulatedV
ehic
les
• Three- wheelerswithsinglesteeringwheelinfront&rearaxlea
sdrivingaxle
• Itcanturnarounditsowntailwithgreaterhandlingability
• Acouplingmechanismbetweensemitrailerandtractorinmostc
a
s
e
sdesignedfor
automaticconnection

18
• HeavyT
ractorV
ehic
les
• Moreheavyloadtractorsorindependenttractorvehicles
• Commonlyoperateinpaireitherintandemora
spullerorpusher
• U
s
e
snumberofaxles&wheelsa
sdrivewheelsorotherwise
• Loadperaxlecanbereducedwhichprotectstyresfromoverloadingandroadsurface
fromdamage
• Wheelaxlesarecalled“live”if driveandcalled“dead”if non-drive
• Aliveaxlesupportsthepayload&drivingtractiveeffortwhiledeadaxlesupportsload only

Car body details – The motor car
o Thepassengercarisusedfortransportationofonetose
venpassengersinsitting
positionandaccommodatestheirluggage.
o Spaceisprovidedforengine,transmission,steering,suspension,brakingsystems,
etc.
o Itisdesignedforsafety
,comfortandeconomy
CarbroadlyclassifiedonBodyStylea
s:
a)Closedcars
b) Opencars
c)SpecialStyles
;Saloon,Coupe,…
;Sports,Convertible,…
;Estate,StationWagon,…
19

Car body Construction
Identification&FunctionsofBody Pressings
o Inaseparatebodyandc
hassisconstruction
o Chassisresistsbending&twistingloads
o Bodyprovidesonlyfunctionalneeds
o Separatebody&c
hassistypeofconstructionisbeingsupersededbytheintegralor
mono-constructionsystem
o Inintegralconstructiontheframemembersbecomeanintegralpartofthe body
20

Car body Construction
Carbodyassemblies
21

Car body terminology
22

Car body terminology
23

Body Components
24
1. OuterBody Components
2. WeatherStrips
3. GlassandMirrors
4. MovableParts
5. Windshield Wiper
6. V
ehicleLightingandSignalling

Vehicleclassification
25
Distinctivegroupsof passengervehiclebodiesinclude
thefollowing
o Small-bodiedmass-producedvehicles
o Medium-bodiedmass-producedvehicles
o Large-bodiedmass-producedvehicles
o Modified mass-produced bodywork to give a
standard production model a more distinctive
appearance
o Speciallybuiltvehiclesusingthemajorcomponentsof
mass-produced models
o High-qualitycoach-builtlimousines(handmade)
o SportsandGTbodywork(mass-produced)
o Speciallycoach-builtsportscars(hand made).

Vehicleclassification- Stylingforms
26
SaloonThemostpopularstyleforpassengerv
ehiclesisthetwo-doororfour-
doorsaloon.Ithas
afullyenclosed,fixed-roofbodyforfourormorepeople.Thisbodystylealso
hasaseparateluggageorbootcompartment
Hatchback Thisbody styleisidentifiedbyitscharacteristicsslopingrear tailgate,
whichisc
lassedasoneof thethreeorfivedoors.Withtherearsea
ts downthere
is no division between the passenger and luggage compartments and this
increasestheluggagecarryingcapacityofthevehicle
EstateThistypeofvehicleisstyledsothattheroofextendstothereartogive
moreluggagespace,especiallywhentherearsea
tsare lowered
Sports coupé and coupé A sportscoupé isatwo-seater sportscarwithafixed
roof and a high performance engine. A coupé isa two-door, fixed roof, high-
performancevehiclewithsimilarstylingbutwithtwoextrasea
tsattherear
, andis
sometimesreferredtoasa‘2-plus-2’

Vehicleclassification- Stylingforms
27
Convertible or cabriolet Thiscanhaveeithertwoorfourdoors.Ithasasoft-topfoldingroof (hood)
andwind-upwindows,togetherwithfullyenclosedoropen bodywork
Sports Thisisatwo-seatervehiclewithahighperformanceengineandafoldingorremovable
roof (hood)
Limousine Thisvehicleischaracterizedbyitsextendedlength,ahighrooflinetoallowbetter
headroomforseatingfivepassengerscomfortablybehindthedriver
,ahigh-qualityfinishand
luxuriousinteriors

Theevolutionofdesign
28
The planning, design, engineering and
development of anewmotor carisan extremely
complex process. With approximately 1
5 000
separate parts, the car is the most complicated
piece of equipment built using m
a
ss production
methods.
Computer-aided design (CAD) Computer-
assisteddesignwork,basicallyusinggraphics.
Computer-aided engineering (CAE) All computer
aided activities with respect to technical data
processing, from idea to preparation for
production,integratedinanoptimumw
a
y
.

Theevolutionofdesign
29
Computer-aided manufacturing (CAM)
Preparation of production and analysis of
production processes.
Computer-integrated manufacturing (CIM) All
computer-aided activities from idea to serial
production.

Stagesofthedesignprocess
30
Thevariousstagesofthedesign process
area
sfollows
o V
ehic
lestyling,ergonomicsandsafety
o Productionofscaleandfull-sizemodels
o Engineperformanceandtesting
o Windtunnel testing
o Prototypeproduction
o Prototypetesting
o Bodyengineeringforproduction

Vehiclestyling,ergonomicsandsafety
31
V
ehiclestyling
Theautomotivestylistneedstobea combination
ofartist,inventor
,craftsmanand engineer
,withthe
abilitytoconceivenewand imaginative ideasand
tobring theseideasto economicrealitybyusing
up-to-datetechniques andfacilities.
He must have a complete understanding of the
vehicle and its functions, and a thorough
knowledge of the materials available, the costs
involved, the capabilities of the production
machinery
, the sources of supply and the
directionsofworldwidechanges.

32
V
ehiclestyling
Hisresponsibilitiesincludetheconception, detail,
design and development of all new products,
both visual and mechanical. This includes the
exterior form, all applied facias, the complete
interior
,controls,instrumentation, seating,andthe
coloursandtexturesof everythingvisibleoutside
andinsidethevehicle.

33
Ergonomics
Ergonomics is a fundamental component of the process
of vehicle design. It is the consideration of human
factors in the efficient layout of controls in the driver ’
s
environment. In the design of instrument panels, factors
such as the driver’s reach zones and his field of vision,
together with international standards, all have to be
considered.
Legal standards include material performance in relation
to energy absorption and deformation under impact.
The vision and reach zones are geometrically defined,
and allow for the elimination of instrument reflections in
thewindshield.

34
E
rgonomics
Bas
ic elements affecting the driver’s
relationship to the instrument panel
controls, instruments, steering wheel,
pedals,sea
tsand othervitalelementsin the
cararepositionedforinitialevaluation using
the ‘Manikin’, which is a two- and three-
dimensionalmeasuringtool developeda
sa
resultof numerous anthropometricsurveys
and representing the human figure.
Changesarerecorded until thedesigneris
satisfied that an optimum layout hasbeen
achieved.

35
Safety
Everycarshouldbedesignedwiththefollowingcrash safety
principles in mind
o Theimpactfromacollisionisabsorbedgradually by
controlleddeformationoftheouterpartsof thecarbody
.
o Thepassengerareaiskeptintactaslongaspossible.
o Theinteriorisdesignedtoreducetheriskofinjury
.
Primaryoractivesafety
This refers to the features designed into the vehicle which
reduce the possibility of an accident. These include primary
designelementssucha
sdual-circuitbrakingsystems,anti- lock
brakingsystems,highaerodynamicstabilityandefficient bad-
weather equipment, together with features that mak
e the
driver’senvironmentsafer
,sucha
sefficientthrough ventilation,
orthopaedic seating,improved all-round vision, easyto read
instrumentsandergonomiccontrols.

36
Secondaryorpassivesafety
Ifacrashdoeshappen,secondarysafetydesignshouldprotectthepassengersby
o Makingsurethat,intheeventof anaccident,theoccupantsstayinsidethecar
o Minimizing the magnitude and duration of the deceleration to which they are
subjected
o Restraining the occupants so that they are not injured by secondary impacts
withinthecar
,and,iftheydostrik
epartsof theinsideof thevehicle,making sure
thatthereissufficientpaddingtopreventseriousinjury
o Designingtheoutsideof thevehiclesothattheleastpossibleinjuryiscaused to
pedestrians and others who may come into contact with the outside of the
vehicle.
There are also engineering features such a
s impact energy-absorbing steering
columns, head restraints, bumpers, anti-burst door locks,and self aligning steering
wheels.Anti-burstdoorlocksaretopreventunrestrainedoccupantsfromfalling out
of thevehicle,especiallyduringroll-over.Thechancesof survivalaremuch reducedif
theoccupantisthrownout.

Stagesofthedesignprocess Production
ofscaleandfull-size models
37
Scalemodels
Once the initial designs have been accepted, scale models are
produced for wind tunnel testing to determine the aerodynamic
values of such a design. These models are usually constructed of
wood and clay to allow for modifications to be made easily
. At the
same time, design engineering personnel construct models of
alternative interiors so that locations of instruments can be
determined.

38
Scalemodels
A¼or⅜scalemodelisproducedfromthestylist’sdrawingstoenablethestylistdesignerto evaluate
thethree-dimensionalaspectof thevehicle.Thesescalemodelscanlookconvincingly real.Theclay
surfacesarecovered withthin coloured plasticsheetwhichcloselyresembles genuinepaintedmetal.
Bumpers,doorhandlesandtrimstripsareallcleverlymade-updummies, andthewindowsaremade
ofPlexiglass.Thescalemodelsareexaminedcriticallyandtested. Changestothedesigncanbemade
atthisstage.

39
Full-size models
A full-size clay model is begun when
thescalemodelhasbeen satisfactorily
modified. Itis constructedin asimilar
w
a
y to the scale model but uses a
metal,wood andplasticframecalleda
buck. The clay is placed on to the
framework by professional model
mak
ers, who create the final outside
shape of the body to an accuracyof
0.375mm. Thehighstandardof finish
anddetail resultsinane
x
actreplicaof
the futurefull-sizevehicle.

40
Full-size models
This replica is then evaluated by the
stylingmanagementandsubmitted to
top management for their approval.
Theaccuratelife-size modelisusedfor
furtherwindtunnel testingandalsoto
provide measurements for the
engineering and production
departments. A scanner
, linked to a
computer
,passes overtheentirebody
and records each and every
dimension.Theseare storedand can
beproduced onan
automaticdraftingmachine.

Engineperformanceandtesting
must be wellinhandbythistime.
Compiled & Edited By VelmuruganSivaraman 1/ 20/ 2016
41
Engineperformanceandtesting
Development engineers prepare to test an engine in a
computer-linkedtestcelltoestablishtheoptimumsettings for
best performance, economy and emission levels. With the
increasing emphasis on performance with economy
,
computersareusedtoobtainthebestpossiblecompromise.
Theyarealso used to monitor and control prolonged engine
testingtoestablishreliabilitycharacteristics.If current engines
and transmissions are to be used for a new model, a
programme of refining and adapting for the new installation
hastobeinitiated.
Howe
ver
,if acompletelynewengine,transmissionor driveline
configurationistobeadopted,developmentwork

Aerodynamicsandwindtunneltesting
42
Aerodynamics is an experimental science whose aim is the study of the
relativemotionsof asolidbodyandthesurroundingair
.Itsapplication to
thedesignof acarbodyconstitutesoneof thechieflinesof the searchfor
energyeconomyinmotorvehicles.
Inordertomoveoverflatground,acarmustovercometwoforces
o R
esistancetotyretreadmotion,whichvarieswiththecoefficientof
tyrefrictionoverthegroundandwiththevehicle’smass.
o Aerodynamicresistance,whichdependsontheshapeof thecar
,on
itsfrontalarea,onthedensityof theairandonthesquareof the
speed.
An aerodynamic or streamlined body allows faster running for the same
consumptionof energy
,orlowerconsumptionforthesamespeed.

43
R
esearch for the ideal shape is done on reduced-scale models of the
vehicle. The models are placed in a wind tunnel, an experimental
installation producing wind of a certain quality and fitted with the
meansformeasuringthevariousforcesduetotheactionof thewind on
themodelorthevehicle.Moreover
,atagivencruisingspeed,the more
streamlinedvehiclehasmorepowerleftavailablefor acceleration:thisis
asafetyfactor
.
Thedesignof amotorcarbodymust,however
,remaincompatible with
imperatives of production, of overall measurements and of inside
spaciousness. It is also a matter of style, for the coachwork must be
attractive to the public. This mak
es it impossible to apply the laws of
aerodynamics literally
. The evolution of the motor car nevertheless
tendstowardsagradualreductioninaerodynamicresistance.

44
Aerodynamicdrag
Theforcewhichopposestheforwardmovementofanautomobileisaerodynamicdrag,inwhichairrubs
againsttheexteriorvehiclesurfacesandformsdisturbancesaboutthebody
,therebyretardingforward
movement.Aerodynamicdragincreaseswithspeed;thusifthespeedofavehicleisdoubled,the
correspondingenginepowermustbeincreasedbyeighttimes.Engineerse
xpressthemagnitudeof
aerodynamicdragusingthedrag coefficient Cd.Thecoefficiente
xpressestheaerodynamicefficiencyof the
vehicle:thesmallerthevalueofthecoefficient,thesmallertheaerodynamicdrag.
Overtheyears,thevalueofCdhasbeenreducedroughlya
sfollows:
1
9
1
00.95 1
9
6
00.40
1
9
2
00.82 1
9
7
00.36
1
9
3
00.56 1
9
8
00.30
19400.45 1
9
9
00.22
1
9
5
00.42 1
9
9
30.20

Prototypeproduction
45
Prototypeproduction
The new model now enters the prototype phase. The mock-ups give
w
a
y to the first genuine road going vehicle, produced with the aid of
accuratedrawingsandwithoutcomplextoolingandmachinery
.
Theprototypemustaccuratelyreproducethee
xactshape, construction
andassemblyconditionsofthefinalproductionbodyit representsif itis
to beof anyvaluein illustratingpossible manufacturingproblemsand
accuratetestdata.Theprocessbegins withtheissueof drawingoffice
instructionsto theexperimental prototype workshop.

Prototypeproduction
46
Prototypeproduction
Details of skin panels and other large
pressings are provided in the form of
tracings or a
s photographic
reproductions of the master body drafts.
Asthevariousdetailedpartsaremade, by
either simple press tools or traditional
handmethods, theyarespotwelded into
minorassembliesorsubassemblies; these
laterbecomepartof amajor assemblyto
formthecompletedvehicle body
.

Prototypetesting
47
Prototypetesting
Whilst still in the prototype stage, the new car has to
faceanumberof arduous tests.Forthesetestsa mobile
laboratoryisconnectedtothevehiclebya cable,which
transmits signals from various sensors on the vehicle
bac
k to the on-board computer for collation and
analysis. The prototype will also be placed on a
computer-linked simulated rig to monitor
, through
controlled vibrations, the stresses and strains
experiencedbythedriveline,suspensionandbody
.

Prototypetesting
48
Prototypetesting
Crashtestingisundertakentoestablishthatthevehicle will
suffer the minimum of damageor distortion in the event
of an impact and that the occupants are safely installed
within the strong passenger compartment or safety cell.
Thebasiccrashtestisafrontalcrashat30 mile/h(48km/h)
into a fixed barrier set perpendicularly to the car’s
longitudinalaxis.
The collision is termed 1
0
0 per cent overlap, as the
completefrontof thecarstrik
esthebarrierandthereis no
offset. The main requirement is that the steering wheel
mustnotbemovedbackbymorethan12
0mm(5 in),but
thereisnorequirementtomeasuretheforceto whichthe
occupantswillbesubjectincollision.

Prototypetesting
49
Prototypetesting
Extensiv
edurabilitytestsareundertakenona variety
ofroadsurfacesinallconditions.V
ehic
les arealsorun
throughwatertestsandsubjectedto extremeclimatic
temperaturechangesto confirm theirdurability
.The
final stages are now being reached; mechanical
specifications,trimlevels, engineoptions,bodystyles
andthefeaturelistsare confirmed.

Bodyengineeringforproduction
50
The body engineering responsibilities are to
simulate the styling model and overall
requirements laid down by the management in
terms of drawings and specification. The
engineering structures are designed for
production,atagivendate,atthelowest possible
toolingcostandtoahighstandardof qualityand
reliability
.
As competition between the major car
manufacturers increases, so does the need for
lighter and more effective body structures.Until
recently the choice of section, size and metal
gaugesw
a
sbaseduponprevious experience.

51
Howev
er
,methodshavenowbeen evolved which allow
engineers to solve problems with complicated
geometry on a graphical display computer which can
beconstructedtoresembleabody shape.The stiffness
and stress can then be computed from its geometry
,
and calculations made of the load bearing of the
structuresusingfinite-element methods.With thefinal
specifications approved, the new car is ready for
production.Atthisstageaninitialbatchof carsis built(a
pilot run) to ensure that the plant facilities and the
workforce are ready for the start of full production.
Whentheproductionlinebeginstoturnoutthebrand
new model, every stage of production is carefully
scrutinized to ensure quality in all the v
ehicles to be
built.

Regulations
52
Regulations
The governments in most countries
have some form of regulations
covering vehicle safety. These
regulations are aimed at giving both
the occupants of the vehicle
protection in the c
a
se of an accident,
and ensuring that pedestrians and
cyclistsarenot subjectto unnecessary
injury if they comeinto contactwitha
car. Theregulations are in most c
a
s
e
s
veryminimal.
Frontimpacttest
Frontal impact takes place at 64 kph
(40 mph) when a car strikes a
deformable barrier that is offset. This
test is similar to many road accidents
where one car hits another car, or
anotherobject,offsettooneside.

Regulations
53
Regulations
Sideimpacttest
This is similar to accidents
wherethecarishitby another
on theside.The impacttak
es
place at 50 kph (30 mph)
when a trolley with a
deformable front is towed
intothedriver’ssideof the car
tosimulateaside-on crash.

Regulations
54
Regulations
Poletest
In this test, the car being tested is propelled
sidewaysat29 kph (18mph) into arigid pole.
The pole is relatively narrow
, like a telegraph
pole of lamp post, so there is major
penetration into the side of the car
. In an
impact without the head protecting airbag, a
driver’s head could hit the pole withsufficient
forcetocauseafatalheadinjury
.

Regulations
55
Regulations
Pedestrianimpacttest
A series of tests are carried out to
replicate accidents involving child and
adult pedestrians where impact occurs
at 40 kph (25 mph) – maximum speed
inbuildup areasinF
rance.Impact sites
are then as
s
es
sed and rated fair
, w
e
a
k
and poor
.

Methodsof construction
56
Thesteelbodycanbedividedintotwomaintypes
Thosewhicharemountedonaseparatec
hassisframe,andthose in
whic
htheunderframeorfloorformsanintegralpartofthe body
.
Theconstructionoftoday’smass-producedmotorcarhas changed
almost completely from the composite, that is conventional
separate c
hassis and body
, to the integral or mono unit. This
changeistheresultoftheneedto reducebody
.
o Compositeconstruction(conventionalseparatec
hassis)
o Integral(monoorunity)construction
o Semi-integralmethodsofconstruction
o Glassfibrecompositeconstruction
o Galvanizedbodyshellcladentirelywithcompositeskin
panels
o V
ariationsinbodyshape

preassembledinunitstoformacompletebody shell.
57
Compositeconstruction(conventionalseparatechassis)
Thec
hassisandbodyarebuilta
stwoseparateunits. The
bodyisthenassembledontothec
hassiswith mounting
brack
ets, which have rubber-bushed bolts to hold the
bodytotherigid c
hassis.Theseflexible mountingsallow
thebodytomoveslightlywhenthe carisinmotion.
Thismeansthat the carcanbe dismantled into the two
units of the body and c
hassis. The c
hassis assembly is
builtupof engine,wheels,springsandtransmission. On
tothisassemblyisaddedthebody
,whichhasbeen

58
Integral(monoorunity) construction
Integral body construction employs the same principles of
designthathavebeenusedforyearsintheaircraftindustry
. The
mainaimisto strengthenwithoutunnecessaryweight,and the
construction does not employ aconventional separate c
hass
is
frame for attachment of suspension, engine and other c
hass
is
andtransmissioncomponents.
The major difference between composite and integral
constructionishencethedesignandconstructionof thefloor
.
In integral bodies the floor pan area is generally called the
underbody
.Theunderbodyismadeupof formedfloor sections,
channels, boxed sections, formed rails and numerous
reinforcements. In most integral underbodies a suspension
memberisincorporatedinboththefrontandrearof thebody

59
Semi-integral methods of
construction
Insomeformsof integralor mono
assemblies,theentirefront endor
subframe forward of the
bulkhead is joined to the co
wl
assembly with bolts. With this
construction, the bolts can be
easilyremovedandtheentire front
(or in some c
a
s
e
srear) subframe
canbe replaced a
sone assembly
intheeventof extensivedamage.

60
Glassfibrecompositeconstruction
Thismethodof producingcomplexshapes involvesapplyinglayersof glass
fibreandresinina preparedmould.Afterhardening,a strong mouldingis
producedwithasmoothoutersurfacerequiringlittle maintenance.Among
the many shapes available in this composite material are lorry cabs, bus
frontcanopies,containervehicles,andthe bodiesofcars.
This allows the panels to be bolted directly to the supporting square-
section steel tube armatures located on the main c
hassisframe. The inner
body
,whichrestsdirectlyonthec
hass
isframeandwhichformsthebase for
allinternaltrimequipment,isacomplexGRPmoulding.
The windscreen aperture is moulded as a part of the inner body
, and
incorporatessteelreinforcinghoopswhicharebraceddirectlytothe chassis.
Thebootcompartmentisalsoaseparatehand- laidGRP moulding,a
sare
the doors and some of the other panels. Most of the body panels are
securedbyself-tappingboltswhichofferverypositive locationandauseful
savinginassemblytime.

61
Galvanizedbodyshellcladentirelywithcompositeskinpanels
Renaulthavedesigneda high-risecar whichhasa skeletalsteelbody shell,
cladentirelywithcompositepanels.Afterassemblythecomplete bodyshell
isimmersedinabathofmoltenzinc,whichappliesanall-over
6.5 micron (millionth of a metre) coating. The process gives anti-rust
protection, while the chemical reaction caus
es a molecular change in the
steelwhichstrengthensit.Lighter-guagesteelcanthereforebeused without
sacrificingstrength,resultinginasubstantialweightsavingeven withthezinc
added.
Skinpanelsareformedinreinforcedpolyestersheet,madeofequalparts of
resin, fibreglass and mineral filler
. The panels are joined to the galvanized
frameanddoorsbyrivetsor bondingasappropriate.The one-piecehigh-
rise tailgate is fabricated entirely from polyester with internal steel
reinforcements. Damage to panels through impact shoc
ks is contained
locally and absorbed through destruction of the material, unlike the steel
sheet which transmits deformation. Accident damage and consequent
repaircostsarethus reduced.

62
Variationsinbodyshape
Amongthemotorcarmanufacturerstherearevariations in
constructionalmethodswhic
hresultindifferentbody types
andstyles.Fourtypesof bodyshell– asaloonwitha boot,a
hatchback,anestatecarandalightvan.
Figure on the right sho
ws a coach-built limousine of
extremely high quality
, built on a Rolls-Royce Silver Spirit
c
hassisbythecoach-buildersHooper&Co.Thisvehicle has
been designed for the use of heads of state and world-
ranking VIPs.

Basicbodyconstruction
63
Atypicalfour-doorsaloonbodycanbelikened to
a hollow tube with holes cut in the sides. The
bulkhead towards the front and rear completes
the box-like form and as
s
i
s
ts in providing
torsional stability
. The roof, even if it has to
accommodate a sunshine roof, is usually a quite
straightforward and stable structure; the curved
shape of the roof panel prevents lozenging
(goingoutofalignmentinadiamond shape).

64
The floor is a complete panel from front to
rear when assembled, and is usually fitted
with integral straightening ribs to prevent
lozenging. With its bottom sides or sill
panels, wheel arches, cross members and
heelboard, it is the strongest part of the
wholebody
.

65
Therearbulkhead,mainlyintheformof a
rear squab panel, is again a very stable
structure.
Howev
er
, the scuttle or forward bulkhead
is a complex structure in a private motor
car
. Owing to the awkward shape of the
scuttle and the accommodation required
for much of the v
ehicle’s equipment, it
requires careful designing to obtain
sufficientstrength.

66
Bodysideswiththinpillars,large windows
and door openings are inherently w
eak,
requiring reinforcing with radiusing
corners to the apertures to give them
sufficientconstructional strength.
Theproblemsarebasicallythesame:
o tomaintainstrengthandstability
,
o agoodstandardoffinishand
o easeofproduction.

Structureofthebodyshell– Mainfloorunit
67
Figureintherightsho
wsthebuild-up detailsof a four
door saloon, from the main floor assembly to the
completeshellassembly
.
Unit(1),Mainfloorunit
Themainfloor commencing atthe front, comprisesa
toeboard or pedal panel, although in some c
a
s
e
sthis
maybecome apart of the scuttleor bulkhead. Apart
from providing arest for the front passengers’ feet, it
seals off the engine and gearbox from the body and
connectsthescuttletothemainfloor
.

Structureofthebodyshell– Maincentrefloorpanel&A
c
c
e
s
sHoles
68
Unit(2), Maincentrefloor panel
The main centre floor panel should be
sufficientlyreinforced to carry the weight of the
frontsea
tsand passengers.
Unit(3),AccessHoles
Itmaybenecessarytohaveatunnelrunning the
length of the floor in the centre to clear the
transmissionsystemfrom theengine to therear
axle,andholesmayhavetobecutintothe floor
to allow a
c
c
e
s
s to the gearbox, oil filler
, and
dipstick,inwhichca
s
eremovablepanelsor large
grommetswouldbefittedinthesea
c
c
e
s
sholes.

Structureofthebodyshell– BottomSills
69
Unit(4),BottomSills(RH&LH)
The front end of the main floor is fixed to
the toeboard panel and the sides of the
main centre floor are strengthened by the
bottom sills and / or some form of side
members which provide the necessary
longitudinal strength.
The transverse strength is provided by the
cross members. The floor panel itself
prevents lozenging, and the joints between
side members and cross members are
designedtoresisttorsionalstresses.

Structureofthebodyshell– Rearseatheelboard
70
Unit(5),Rearseatheelboard
The rear end of the floor is stiffened
transverselybytherearseatheelboard. This
heelboard also stiffens the front edges of
the rear seat panel. In addition it often
provides the retaining lip for the rear seat
cushion, which is usually made detachable
from the body
. The heelboard, together
with the rear panel and rear squab panel,
formstheplatformfortherearseat.

Structureofthebodyshell– Rearseatpanel
71
Unit(6),Rearseatpanel
The rear sea
t panel is reinforced or s
waged if
necessary to gain enough strength to support
the rear passengers. Usually the rear sea
t panel
has to be raised to provide sufficient clearance
for the deflection of the rear axle differential
housing.Thefrontedgeof therearseatpanel is
stiffenedbytherearsea
theelboard,andthe rear
edge of the sea
t panel is stiffened by the rear
squab panel. The rear squab panel completes
this unit and provides the rear bulkhead across
the car
. It seals off the boot or luggage
compartmentfromthemainbodyor passenger
compartment.

Structureofthebodyshell– Bootfloor,Crossmember
,Wheelarchpanel
72
Unit(7),Bootfloor
Thebootfloor
,whichextendsfromthebac
kofthe rear
squab panel to the e
xtreme bac
k of the body
,
completes the floor unit. In addition to the luggage,
thesparewheelhastobeaccommodatedhere.
Unit(8),CrossMember
The front edge of the boot floor is reinforced by the
rearsquabpanelandtherearendbyacross member
of someform. The sidesof the floor are stiffened by
vertical boot side panels at the rear
, while the wheel
archpanelscompletethefloor structurebyjoiningthe
rearendofthemainfloor anditssidemembers.
Unit(9),Wheelarchpanel(RH&LH)
Thewheelarchpanels(9)themselvessealtherear road
wheelsfromthe body
.

Structureofthebodyshell– Rearsquabs
73
Unit(10),Rearsquabs
In general the floor unit ismade up from a
seriesofpanelswithsuitable cross members
or reinforcements.Theedgesof thepanels
are stiffened either by flanging reinforcing
members, or by joining to the adjacent
panels. The boot framing is joined at the
bac
ktotherearendof theboot floor
,atthe
sidestothebootsidepanels andatthetop
totheshelf panelbehind therearsquab.

Structureofthebodyshell– Bootlitlockstrikingplate
74
Unit(11),Bootlitlockstriking plate
It has to be sufficiently strong at the point
where the boot lid hinges are fitted to
carrytheweightof thebootlidwhenthis is
opened. Surrounding theboot lid opening
there is a gutter to carry aw
ay rain and
water to prevent it entering the boot;
opposite the hinges, provision is made for
thebootlidlockstrikingplateto befixed.

Structureofthebodyshell– Roofstructure,Canopyrail,Cantrial, A-post
75
From the forward edge of the boot, the ne
xt
unit is the bac
k light and roof structure (Unit
12), and this extends to the top of the
windscreenor canopyrail(Unit13).Theroof is
usually connected to the body side frames,
which comprise longitudinal rails or stringers
andapairof cantrails(LH&RH)whichform the
door openings (Unit 14). Provision in the roof
should be made for the interior lights and
wiring and also the fixing of the interior
trimming. The scuttle and windscreen unit,
including the front standing pillar or A-post
(LH&RH)(Unit15),providesthefront bulkhead
and seals the engine from the passenger
compartment.

Structureofthebodyshell–Scuttle
76
Unit(16),Scuttle
Accommodation has to be made for the
instrumentationof thecar
,thewiring, radio,
windscreen wipers and driving cable,
demisters and ducting, steering column
support,handbrakesupportandpedals.
Thescuttleisacomplicatedstructure which
needs to be very strong. When the front
door is hinged at the forward edge,
provision hasto be made in the front pillar
for the door hinges, door c
hec
k and
courtesylights
witc
hes.

Structureofthebodyshell– Centrestandingpillar (BC-Post)
77
Unit(17),Centrestandingpillar(BC– post)
Thecentrestandingpillar or BC-post (LH&
RH)isfixed tothesidemembersofthe main
floor unit and supports the cantrails of the
roof unit.Itprovidesashutfacefor thefront
door
, a position for the door lock striking
plate and buffers or dovetail, and also a
hinge face for the rear door; a
s with the
front standing pillar
, provision is made for
thedoorhingesanddoorcheck.

Structureofthebodyshell– Rearstandingpillar(D–post)
78
Unit(18),Rearstandingpillar(D– post)
Therearstandingpillaror D-post(LH& RH)
provides the shut face for the rear end of
thefloorsidemembersatthebottom, whilst
the top is fixed to the roof cantrails and
formsthefrontofthequarters.

Structureofthebodyshell– Quarterpanels
79
Unit(19),QuarterPanels
Thequarters (19)aretheareasof thebody
sides between the rear standing pillars and
thebac
klightandboot.If thebodyisa six-
light saloon therewillbe aquarter window
here with its necessary surrounding
framing, but in the cas
e of a four-light
saloon this portion will be more simply
constructed.
Apart from thedoors, bonnet, boot lid and
front wings this completes the structure of
theaveragebodyshell.

Identificationofbodypressings– Majorbody panels
80
Thepassenger-carryingcompartmentofcar is
called the body, and to it is attached all the
doors, wingsand suchpartsrequired to form
acompletebodyshellassembly.
Majorbodypanels
1. Roofpanel
2. Bonnetpanel
3. Bootlid
4. Frontwing
5. Radiatorgrille
6. Frontbumper bar
7. Headlamps
8. Sidelamps
9. Sillpanel
10. Frontdoor
11. Reardoor
12. Centrepillar
13. Rearquarterpanel
14.Rearbumperbar

Identificationofmajorbodypressings– Bodyshellassembly
81
Outerconstruction
This can be likened to the skin of the
body, and is usually considered a
sthat
portion of a panel or panels which is
visiblefromtheoutsideofthe car.
Innerconstruction
This is considered a
s all the brackets,
races and panel assemblies that are
usedto give the carstrength (Figure in
right). In some c
a
s
e
s the entire panels
are inner construction on one makeof
car and a combination of inner and
outeron another.
1
Underbodyassembly
2 Boysideframeassembly
3 Windscreenupperrailassembly
4 Cowlanddashpanelassembly
5 Frontwheelhousecompletepanel
6 Instrumentpanel assembly
7 Cowlsidelowerbrace
9. Roofpanelassembly
10. Roofbow assembly
11. Bulkheadbraceassembly
12. Rear quarter centre assembly
(Ba
c
kwindow)
1
3
. B
a
c
kwindowupperrailpanel
assembly
14. Rear-endupperpanel assembly
15. Radiatorpanelcomplete assembly
16. Centrepillar(BC-post)
17. D-post
18. Rearquarterassembly
19. Sillpanel
20. Frontsidememberassembly
21. Rearwheelarchassembly
22. Mainfloor assembly
23. Frontvalancecompleteassembly
8 Frontbodyhingepillar (A-post)

Identificationofmajorbody pressings
Front-endassemblyincludingcowlordashpanel
82
Thefront-endassemblyismadeupfrom the
twofrontsidememberassemblies whichare
designed to carrytheweightof theengine,
suspension,steeringgearand radiator.
The suspension system used will affect the
designof thepanels,butwhatever system is
used the loads must be transmitted to the
wing valances and on to the body panels.
Thefrontcrossmemberassemblybraces the
front of thecarandcarriestheradiator and
headlampunits.
Theside valanceassemblies form ahousing
forthewheels,amatingedgeforthe bonnet
and astrong box section for attachment of
frontwings.Boththeside framesandvalance
assemblies are connected to the cowl or
dash panel, The front-end assembly is
attachedtothemain
Completefront-endassemblies
24.A-postfrontreinforcementRH&LH
flooratthetoepanel.
1. HeadlamppanelRH&LH
2. Frontcrossmemberclosing panel
3. Frontcrossmember
4. Bonnetlockpanel
5. HeadlamppanelreinforcementRH&LH
6. FrontwingcornerpieceRH&LH
7. Bonnetframeextension
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
13. ChassislegreinforcementRH&LH
14. Front innerwing RH&LH
15. Front chassislegRH&LH
16. SubframemountingRH&LH
17. FrontwheelarchRH&LH
18. FrontwingRH&LH
19. Batterytray
20. ChassisleggussetRH&LH
21. BumpermountingreinforcementRH&LH
22. ChassislegextensionRH&LH
23. A-postrearreinforcementRH&LH

83
The cowl or dash panel forms the front
bulkhead of the body and isusually formed
by joining smaller panels (the cowl upper
panel and the cowl side panel) by welds to
formanintegralunit.
In some c
a
s
e
s the windscreen frame is
integral with the cowl panel. The cowl
extends upwards around the entire
windscreenopening sothattheupper edge
ofthecowlpanelformsthefrontedgeof the
roofpanel.
In this case the windscreen pillars, i.e. the
narrowslopingconstructionateitherside of
thewindscreenopening, aremerelypart of
thecowlpanel.Inotherconstructions, onlya
portionofthewindscreen pillaris formeda
s
partofthecowl.
22.ChassislegextensionRH&LH
23.A-postrearreinforcementRH&LH
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray

84
The cowl is sometimes called the fire wall
because it is the partition between the
passenger and engine compartments, and
openings in the cowl accommodate the
necessary controls, wiring and tubing that
extendfromonecompartmenttotheother.
The instrument panel, which is usually
considered as part of the cowl panel
although it is a complex panel in itself,
provides a mounting for the instruments
necessary to check the performance of the
vehicle during operation. Cowl panels
usually have both inner and outer
construction, but in certain constructions
only the upper portion of the cowl around
thewindscreenisvisible.
Onmanyvehiclesthefrontdoor hinge
pillarisalsoanintegralpartofthecowl.
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray

Identificationofmajorbodypressings
Frontsidememberassembly
85
Frontsidememberassembly
This is an integral part of the
front-end assembly; it connects
thefrontwingvalancestothe cowl
or dashassembly
.Itis designedto
strengthenthefront end;itispart
of the crumple zone, giving
lateral strength on impact and
absorbing energyby deformation
during a collision. It also helps to
supportthe engine
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
17.FrontwheelarchRH&LH
18.FrontwingRH&LH
19.Batterytray
20.ChassisleggussetRH&LH
21.BumpermountingreinforcementRH&LH
andsuspension units.

A-postassembly
86
A-post assembly
Thisisanintegralpartof thebody
side frame. It is connected to the
front end assembly and forms the
front door pillar or hinge post. Itis
designed to carry the weight of
the front door and helps to
strengthen the front bulkhead
assembly
.
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
17.FrontwheelarchRH&LH
18.FrontwingRH&LH
19.Batterytray
20.ChassisleggussetRH&LH

Mainfloor assembly
87
Mainfloor assembly
Thisisthepassenger-carrying sectionof the
main floor. It runs backwards from the toe
panel to the heelboard or back seat
assembly. Itisstrengthenedtocarrythe two
front seats, and in some c
a
se
smay have a
transmission tunnel running through its
centre.Strengthisbuiltintothefloor by the
transmission tunnel acting like an inverted
channelsection.
The body s
ill panels provide extra
reinforcement in the form of lateral
strength. Transversestrength isprovided by
box sections at right angles to the
transmissiontunnel,generallyintheareas of
the front seat and in front of the rear seat.
Theremaining areasof flat floor are ribbed
belowthese
a
tsandinthefootwells
Mainfloorassemblies&bootfloorassemblies
15.SidememberfrontfloorLH/ RH
toadd stiffness.
1. Reinforcedparkingbrakelever
2. Crossmemberassemblybackbone
3. Reinforcementassemblybackbone
4. BracketA-frameLH
5. BracketA-frameRH
6. Panfrontfloor
7. Crossmemberassemblyfrontfloorfront RH
8. Crossmemberassemblyfrontfloorrear RH
9. Crossmemberassemblyfrontfloorrear LH
10. Crossmemberassemblyfrontfloorfront LH
11. ReinforcementseatbeltsideLH/ RH
12. Bracketantizipper
13. SillfrontfloorsideinnerLH/ RH
14. ReinforcementsidememberfrontfloorLH/ RH

Bootfloorassembly
88
Bootfloorassembly
Thisisa sectionofthefloorbetween the
seatpanel and the e
xtremebackof the
boot. It is strengthened by the use of
cross members to carry the rear seat
passengers.
This area forms the rear bulkhead
between the two rear wheel arches,
forming the rear seat panel or
heelboard, and in a saloon body shell
can incorporate bac
k seat supports and
parcel shelf
. The boot floor is also
strengthened to become the luggage
compartment, carrying the spare wheel
and petrol tank. At the e
xtreme bac
k it
becomesthepanelontowhichthe
14.ReinforcementsidememberfrontfloorLH/ RH
doorortailgatecloses.
4. BracketA-frameLH
5. BracketA-frameRH
6. Panfrontfloor

Completeunderbody assembly
89
Completeunderbodyassembly
This is commonly called the floor pan
assembly
, and is usually composed of
sev
eral smaller panels welded together to
formasinglefloorunit.Allfloorpanels are
reinforced on the underside by stiffening
members or cross members. Most floor
pans are irregular in shape for sev
eral
reasons.Theyareformedwith indentations
or heavilys
wagedareasto strengthen the
floorsectionsbetweenthe crossmembers,
and foot room for the passengersisoften
provided by these recessed areas in the
floor
.
Figure in the right sho
ws a complete
underbodyassembly
.
4. BracketA-frameLH
5. BracketA-frameRH
6. Panfrontfloor
14.ReinforcementsidememberfrontfloorLH/ RH

Bodysideframeassembly
90
Bodysideframeassembly
Onafour-doorsaloonthisincorporatesthe A-post,
theBC-post,theD-postandtherearquartersection.
The side frames reinforce the floor pan along the sill
sections.ThehingepillarorA-postextendsforward to
meet the dash panel and front bulkhead to provide
strengthatthispoint.
ThecentrepillarsorBC-postsconnectthebodysills to
the roof cantrails. They are usually assembleda
s box
sectionsusing atop-hat sectionand flat plate. These
are the flanges which form the attachments for the
door weather seals and provide the four door
openings.
TheD-postandrearquartersectionisintegralwith the
rearwheelarch andcanincludearearquarter window.
Bodysideassemblies,roof,BC-post,frontandreardoorofahatchback
1. Panelouterrear door
2. Panelinnerrear door
3. Panelouterfrontdoor
4. Panelinnerreardoor
5. Panel hood
6. Panelcowltopinner
7. Panelcowltopouter
8. Panelassemblydash
9. ReinforcementradiatorsideRH
10. Stayhoodlock
11. Crossmemberfrontend
12. ReinforcementradiatorsideLH
13. Barfrontend upper
14. Bulkheadfrontpillarlower
15. Bulkhead frontpillar sidesill
16. Bracketcrossmemberfront
17. Bracketcrossmember
18. Reinforcementpillarfrontinnerlower
19. Pillarfrontinnerlower
20. Sidememberfront
21. Panelfrontfender
22. Panfrontfloor
23. Reinforcementfrontpillarlower
24. Extensionupperframeouter
25. Sidestructure
26. Renforcement.frontpillarcentre
27. Pillarfrontinnerupper
28. Railroofsideinner
29. Railrooffront
30. Pillarcentreinner
31. Pillar centreouter
32. Pillarrearinner
33. Railroofrear
34. Panelroof

Roof panel
91
Roof panel
The roof panel is one of the largest of all major
body panels, and it isalso one of the simplest in
construction. The area which the roof cov
ers
varies between different m
ak
es and models of
cars. On some cars, the roof panel ends at the
windscreen.
On others it e
xtends downwards around the
windscreen so that the windscreen opening is
actually in the roof. On some cars the roof ends
abovetherearwindow
,whileonothersit extends
downwardssothattherearwindow openingisin
thelowerrearroof.Whenthisisthe cas
etheroof
panel forms the top panel around the rear boot
opening.
5. Panel hood
10. Stayhoodlock
20. Sidememberfront
22. Panfrontfloor
25. Sidestructure
29. Railrooffront
32. Pillarrearinner
33. Railroofrear
34. Panelroof

Roof panel
92
Roof panel
Some special body designs incorporate different
methods of rear window construction, which
affects the roof panel; this is particularly true for
estatecars, hatchbacksandhardtop convertibles.
Alternatively the top isjoined to the rear quarter
panel by another smaller panel which is part of
theroof assembly
.Thestiffnessof theroof isbuilt
in by the curvature given to it by the forming
presses, while the reinforcements, consisting of
small metal strips placed cross
wiseto the roof at
intervals along the inside surface,serve to stiffen
the front and rear edges of the windscreen and
rear window frames. In some designs the roof
panel mayhave asliding roof built in or aflip-up
detachablesunroofincorporated.
5. Panel hood
10. Stayhoodlock
20. Sidememberfront
22. Panfrontfloor
25. Sidestructure
29. Railrooffront
32. Pillarrearinner
33. Railroofrear
34. Panelroof

Rearquarterpanelortonneauassembly
93
R
ear quarter panel or
tonneau assembly
Thisisintegral with the side frame assemblyand
hasboth inner and outer construction. The inner
construction comprises the rear wheel arch and
therearseatheelboardassembly
.
Thisprovides the support for the rearseatsquab
in a saloon car; if the vehicle is a hatchback or
estatecar
,thetwo bac
ksea
tswillfoldflatand the
seat squabs will not need support. This area is
known as the rear bulkhead of the car; it gives
additionaltransv
ersestrengthbetweenthe wheel
arch sections and provides support for the rear
seat. The rear bulkhead also act
s as a partition
between the luggage and passenger
compartments.
5. Panel hood
10. Stayhoodlock
20. Sidememberfront
22. Panfrontfloor
25. Sidestructure
29. Railrooffront
32. Pillarrearinner
33. Railroofrear
34. Panel roof

Rearwheelarchassembly
94
Rearwheelarchassembly
Thisassemblyisconstructeda
san
the inner
rear quarter
integral part of
construction of the
panel.Itisusually a two-piece
construction comprising the wheel
archandthequarterpanel,which are
weldedtogether
5. Panel hood
10. Stayhoodlock
20. Sidememberfront
22. Panfrontfloor
25. Sidestructure
29. Railrooffront
32. Pillarrearinner
33. Railroofrear
34. Panel roof

Wings
95
2. Frontcrossmemberclosingpanel
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray
24. A-postfrontreinforcementRH&LH
Wings
A wing is a part of the body whichcovers the
wheel. Apart from covering the suspension
construction, the wing prevents water and
mudfrombeingthrownupontothebody by
the wheels.
The front wings (or the fender assembly) are
usually attached to the wing valance of the
front end assembly by means of a flange the
length of the wing, which is turned inwards
from the outer surface and secured by either
weldingorbolts.
Adjustment for the front wing is usually
provided for by slotting the bolt holes so that
the wing can be moved either forwards or
backwardsbylooseningtheattachingbolts.

Wings
96
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray
Wings
Thisadjustmentcannotbemadeifthewing is
welded to the main body structure. In some
models the headlights and sidelights are
recessed into the front wing and fastened in
place by flanges and reinforcement rims on
thewing.
Anytrimorchrome whichappearsonthe side
of thewingis usuallyheld in placeby special
clipsorfastenerswhichallows easy removalof
thetrim.
The unsupported edges of the wing are
swaged edges known a
s beads. The bead is
merely a flange which is turned inwards on
somecarsandthenuptoformaU-section
witharoundedbottom.

Wings
97
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray
Wings
It not only gives strength but prevents c
r
a
c
k
s
developing in the edges of the wing due to
vibration, and it provides a smooth finished
appearancetotheedgeofthewing.In general
the rear wing is an integral part of the body
sideframeassemblyandrear quarterpanel.
When the wing forms an integral part of the
quarterpanel,theinnerconstructionisused to
form part of the housing around the wheel
arch.Thewheelarchis weldedtotherear floor
section and is totally concealed by the rear
quarterpanel,whiletheoutersideofthe wheel
arch is usually attached to the quarter panel
aroundthewheelopening.
Thisassembly preventsroaddirtbeing thrown
upwardsbetweentheouter panel
andinnerpanelconstruction.

Doors
98
Doors
Several types of door are used on each vehicle built,
although the construction of the various doors is similar
regardless of the location of the door on the vehicle, as
indicatedonFigureintherightside.
Thedoor iscomposedof twomainpanels,anouterand an
inner panel, both being of all-steel construction. The door
derivesmostofitsstrengthfromtheinnerpanel sincethisis
constructedmainlytoacta
saframeforthe door.
The outer panel flanges over the inner panel around all its
edgestoformasingleunit,whichisthenspotweldedor, in
somecases,bonded withadhesivestotheframe.The inner
panel has holes or apertures for the attachment of door
trim.Thetrimconsistsofthewindowregulator assemblyand
thedoor lockingmechanism.These assembliesareinstalled
throughthelargeaperturesinthe middleoftheinnerpanel.
5. Panel hood
10. Stayhoodlock
20. Sidememberfront
22. Panfrontfloor
25. Sidestructure
29. Railrooffront
32. Pillarrearinner
33. Railroofrear
34. Panel roof

Doors
99
Doors
Mostofthethicknessof thedoor isduetothedepthof the
inner panel which is necessary to accommodate the door
catch and window mechanism. The inner panel forms the
lockpillarandalsothehingepillarsectionofthe door.
Small reinforcement angles are usually used between the
outer and inner panel, both where the lock is inserted
throughthedoorandwherethehingesare attachedto the
door. The outer panel is either provided with an opening
through which the outside door handle protrudes, or is
recessedtogiveamorestreamlinedeffect andsotocreate
betteraerodynamics.
Theupperportionof thedoor hasalargeopeningwhich is
closed by glass. The glass is held rigidly by the window
regulatorassembly,andwhenraiseditslidesinachannel in
the opening between the outer and inner panels in the
upper portion of the door. When fully closed the window
seats tightly in this channel, effectively sealing out the
weather.
5. Panel hood
10. Stayhoodlock
20. Sidememberfront
22. Panfrontfloor
25. Sidestructure
29. Railrooffront
32. Pillarrearinner
33. Railroofrear
34. Panel roof

Bootlidortailgate
100
Bootlidortailgate
This is really another door which allows a
c
c
e
s
s to the luggage
compartmentintherearofthecar.Abootlidiscomposedofan outer
andaninnerpanel.Thesepanelsarespotweldedalongtheir flanged
edgestoformasingleunitinthesamemannera
san ordinarydoor.
Thehatchbackand estatecarhavearear windowbuilt into the boot
lid,whichisthenknowna
satailgate.Some manufacturersuse external
hinges,whileothersuseconcealedhingesattachedtothe innerpanel
only. A catch is provided at the lower rear edge of the boot lid or
tailgateandiscontrolledbyanexternalhandleorlocking mechanism.
Thismechanismmaybeconcealedfromtheeyeunder amouldingor
sometypeoftrim.
In some models there is no handle or external locking mechanism;
insteadthehingesarespringloadedorusegas-filledpiston supports,
sothatwhenthelid isunlockedinternallyitautomatically risesandis
heldintheopenpositionbythesemechanisms.

Bonnet
101
Bonnet
The bonnet is the panel which covers the
enginecompartmentwherethisissituated at
the front of the vehicle, or the boot
compartment of a rear-engine vehicle.
Several kinds of bonnets are in use on
different ma
k
esof cars. The bonnet consists
ofanouterpanelandaninner reinforcement
constructed in the H or cruciform pattern,
whichisspotweldedto theouterskinpanelat
theflangededgesof thepanels.
The reinforcement is basically a top-hat
section, to give rigidity to the bonnet. In
someca
s
e
stheouterpanelisbondedto the
inner panel using epoxy resins. This system
avoids the dimpling effect on the outer
surfaceofthebonnetskinwhich
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray
occursinspotwelding.

Bonnet
102
Bonnet
Early models used a jointed type of bonnet
whichw
a
sheldin placeby bolts through the
centre section of the top of the bonnet into
the body of the cowl and into the radiator.A
pianotype hinge w
a
sused wherethe bonnet
hingedbothatthecentreandattheside.
The most commonly used bonnet on later
constructions is known a
sthe mono or one-
piecetype,andcanbeopenedbyavariety of
methods. On some types it is hinged at the
frontso thattherearendswingsup whenthe
bonnetisopen. Othersare designedsothat
they can be opened from either side, or
unlatched from both sides and removed
altogether.Mostbonnets, however,areofthe
alligatorpattern,which ishingedattherearso
thatthefront end
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray
swingsupwhenopened.

Bonnet
103
Bonnet
The type of bonnet catch mechanism
dependsonthetypeofbonnetused.When a
bonnet opens from the rear the catch
mechanismisalsoattherear.Whenit opens
from either side the combination hinge and
catchareprovidedateachside. Thealligator
bonnetshavetheirc
a
tches at thefront,andin
most c
a
s
e
s the catches are controlled from
insidethecar.
Bonnetsarequitelarge,andtomake opening
easierthehingesareusually counterbalanced
by means of tension or torsion springs.
Where smaller bonnets are used the hinges
are not counterbalanced and the bonnet is
heldinplacebyabonnet stayfromthesideof
the wing to the bonnet. Adjustment of the
bonnet position is sometimes possible by
movingthe hinges.
3. Frontcrossmember
4. Bonnetlockpanel
8. Bonnetskin
9. Bonnetframe
10. Dashpanel
11. Scuttlepanel
12. Frontbulkhead
18. FrontwingRH&LH
19. Batterytray
24. A-postfrontreinforcementRH&LH

Comparative terms in com
mon use by B
ritish
,
AmericanandEuropeancarmanufacturers
Bootlid,decklid,trunklid,tailgate
Cantrail,roofsiderail,driprail
Centrepillar
,BC-post
Courtesylight,interiorlight
Cowl,scuttle,bulkhead,firewall
Dashpanel,faciapanel
Dooropeningplates,scuffplates
Doorskin,outsidedoorpanel
F
a
c
ebar
,bumperbar
Frontpillar
,A-post,windscreenpillarLight,
window
104
Quarterpanel,tonneauassembly
Roof
,turret
Roof lining, headlining
Sill panel, rocker panel
Squab,seatbac
k
Underbody
,floorpan assembly
V
alanceoffrontwing,fendersideshield
V
entwindow
,flipperwindow
Waistrail,beltrail
Wheelarch,wheelhouse
Windscreen,windshield
Wing,fender
.
Asmanufacturersusedifferingtermsforthevariousbodypanelassembliesandindividualpanels,
difficultiesmayarisewhenidentifyingspecificpanels.Thefollowingarethetermsinmost common
use:
Bonnet,hood

Body Components
105
a. Bumpers
b. Grilles
c. SillCoversandSideAirdams
d. OuterMoldings
e. Spoilers
2. WeatherStrips
3. GlassandMirrors
4. MovableParts
5. Windshield Wiper
6. V

Body Components - OuterBodyComponents
106
a.Bumpers
Bumperswereusually chrome plated or rolled and formed
stainless steel leafs, the main function being aesthetic
enrichment and protecting the car body against small
impacts.
Basicdesignconcepts
o Front andrear endofvehiclesshould beable toabsorb
energy
o The stiffness of body parts committed to energy
absorption should increase a
s the passengers cabin is
neared.
o The properties of traditional bumper leafs are
completely opposite to those required, a
sthey collapse
inbending,withonlylowlevelsofenergy absorbed

107
a. B
umpers
Designcriteriaand materials
Thedesignspecificationsarerelatedto:
• Impact,forcontactwithpendulumorbarrierandfitting areas.
• Dynamicstress,whereopeningsandnotchescanweakenthe
bumper.
• Thermalandmechanicalstressinproximityofhotparts(eg.
engine,exhaustsystem).
• Abrasionorbreakforgroundcontact,againstrampsor
platforms
Size is related to material choice: for polyolefin (polypropylene,
polypropylene with EPDM) the recommended outer skin is 3÷3.5
mm, if a support metal blade exists; 3.5 mm, if a plastic boxing is
welded to the outer skin; 4.0 mm if the bumper is self supporting.
Plasticboxingrequiresatleast3mmthickness.
Schematicsectionofhighabsorption
frontend:
A) flexibleskin
B) B)supportingbar
C) foaminsert
D) Absorbing/ dampingdevice

108
a. Bumpers
MissionoftheBumpers
o Aesthetics
o Overallbodyprotectioninparkingimpact(upto a
speedof4km/h)
o E
nergy absorption and controlled transfer
of stresstobodyframe,whenimpactedat1
5km/h
o Aerodynamics
o Friendlycontact(orabsenceof injury)incaseof
pedestrian’s impact
o Supportofwinchesortowhooksforoff-road
vehicles

109
a.Bumpers
Designspecificationsof Bumpers
o Aesthetics
Bumpershape,gapswithrespecttoadjacentparts (lamps,
fenders,radiatorgrille,bonnet),color
,roughness(skingrain) are
properties relevant to the aesthetics of the vehicle and are
thereforemodeledandspecifiedbythestylingcenter
.
o Overallbody protection inparkingimpact(upto a
speedof4km/h)
Bumpers,bothfrontandrear
,must enablepermanent functional
damage to the vehicle to be avoided when impacted by a
pendulum of m
as
s equal to the vehicle curb weight, in three
differenttransversepositionandataheightof 445mm fromthe
ground. The vehicle should be tested in three load conditions
(curbweight,threepeopleandfullload).Pendulum impactspeed
is4km/hor2.5km/h,dependingontheimpact position.

110
a.Bumpers
o Energyabsorptionand controlledtransferofstressto
bodyframe,whenimpactedat1
5km/h
Most of road crashesare at lowimpact speed; if the equivalent
barrier speed is higher than 8÷10 km/h, it is usual that the
damage to those cars not equipped with special devices is
relevant and the cost of repair is high. This is due to structural
deformationeveninthebodymainframe(forinstance, front
rails and engine compartment). As a consequence, repair
requiresnotonlyreplacementofthepart,buteventhe complete
removalofthepowertrainandaccessoriesinorder toreshapeor
replacethedeformedbodyframes.Also,itmust beremembered
that parts reshaped by stretching, hammering and welding no
longerexhibittheiroriginalstrength.

111
a.Bumpers
o Aerodynamics
Bumpersperformtw
o mainaerodynamictasks:thefirst,a
sa
body shape part influencing both drag and lift, the second, a
s
flow conveyors or extractors both for the engine compartment
andunderbody
.
o Friendlycontact(orabsenceofinjury)incas
eof
pedestrian’simpact
Specific regulations havebeen proposed in thisarea;asaresult
car manufacturers are forced to develop front bumper design
andsoftnessthatcanachiev
eagoodscoreinsucharating.
o Supportofwinchesortowhooksforoff-road v
ehicles

112
b.Grilles
The main technical goal for a radiator grille is air flow control
through an adequate intak
e duct, between the radiator grille
andradiators(usuallytheairconditioningcondenseris coupled
withtheenginecooling radiator)
Designspecifications
Aesthetics and performance are the principal targets: flow
effectiveness(notonlyintermsof pressurelossesandflow rate,
but also noise, recirculation and water ingress); resistance to
small impact stress, snow loading and contact with external
bodies; resistance to chemical agent deterioration, UV rays,
thermal variations; resistance to painting and chrome coating
radiiaccordingtointernationalsafetystandards.

113
b.Grilles
Designcriteriaof Grilles
For a radiator grille, the most important performance
parametersare:theincidentangleof bladesreferredto the
localairflowvector
,blades shape(profile,distance between
clamps,thickness,length),radiiandframedesign, influenced
by dynamic stresses (aerodynamic pressure, vibrations,
small impacts) a
s well as by the air flow channelling task.
T
ogether with the structural strength of grilles, it is very
important to k
eep the air intak
e energy loss a
s small a
s
possibleand thereforeoptimizegrille profiles.

114
c. SillCoversandSide Airdams
The main purpose being to protect the lower body side
(rocker panels and doors) from corrosion caused by
abrasion due to stones, salt and mud projected from the
wheels.Atthattime,bodysheetswereneverzinccoated and
thereforeabrasionof paintlayerscouldexposesteel sheets
to rapid rusting and deterioration, mostly in countries
affected byicywinterclimateand widespread saltspraying
onroadstocontrasticing.

115
Other advantages of sill co
vers include the opportunity to
modelmorefreelythelowerbodyside,usually conditioned
by the forming process of the upper side and by its size,
improved protectionof door openingfrom dust,mudand
powder
, and possible influence on vehicle aerodynamic
properties.
Nevertheless sill co
vers are additional components in any
case, therefore increasing costs, investments and weight
(from2to4kgper car).

116
c. Sill Covers and Side Airdams
Materials&T
echnology
Manufacturing of sill covers commonly uses high pressure
thermoplastic injection or reaction injection of polyurethane resin
filledwithshortglassfiber
.
Themostusedthermoplasticsare
1. Blend ofPolycarbonate andA
B
S
2. PolybutylenterephtalateP
B
Tand
3. PolypropylenewithEPDM.
Originallymostsillcoverswereblack,whereaslatersomebeganto be
bodycolored.Inrecentyears,bodycoloredsillco
vershave become
predominant.Mountingismadeon thepainted body usingplastic
snapssucha
spine-tree clipsand self threading s
crew
s withplastic
inserts.

117
DesignSpecifications
The main technical properties of
thes
e componentsare
o Amountofsillsurfacecoveredandtherefore
protected
o Position,typeandnumberof fasteners
o Absenceofinterferencewithjigsandfixtures
usedtoliftthe vehicle
o Mechanic
a
l s
trength and environment
resistance
o Whenpossible,aerodynamicperformance.

118
d. OuterMoldings
Thesecomponentsfallintotw
omainfamilies:thefirstrelatesto shieldingof
aestheticdefectssuc
ha
sunsatisfactorysheetjoints,the secondisdesigned
toprotectbodypaintedsheetsfromsmallimpacts. Thefirstfamilyincludes
roof moldings, typically constant section and small size if compared to
molding length. The second includes doors and body side moldings,
constantsectionorshaped.
Inthec
a
s
eofroofmoldings,thesuperpositionofsideouterpaneland roof
panel, whatever the assembly process used, could put in evidence the
trimmed sheets, requiring protection against corrosion and waterproof
sealing.
In the c
a
se of doors, moldings supply a local protection against little
damage occurring in parking operations (for instance, due to door
openingcontact)orinnarrowentrancemaneuvers.

119
d. OuterMoldings
Materials,productionandassemblyprocess
A.Roofmoldings
Themostusedfamiliesare:
i. PVCmoldingwithglassfiberinsert.
ii. PVCmoldingwithmetalinsert.
iii. Metalprofile(aluminum,inoxsteel).
iv. Thermoplasticrubbermoldingwithmetalinsert.
Bothplasticandmetalmoldingscanbefittedprotrudingordrowned.
B.Sideanddoormoldings The
mostcommonfamiliesare:
i. PVCmoldingwithmetalinsert.
ii. PVCmoldingwithglassfiberinsert.
iii. Polypropylene.
iv. PC/ABS.
PVCmoldingsareusuallym
a
s
scolored,butPolypropyleneorPC/ABSbody
coloredmoldingsarethemostdiffused.

120
d. OuterMoldings
Moldingspecifications
Moldingsandimpactguardsshouldbe:
1. Perfectlyfittabletosurfacesandhousingdesignedfortheir insertion
made by material which are resilient even at low temperatures,
scratchresistant,non aggressive,and resistantto chemicals,to UV
rays,andcorrosion;
2. withoutmetalsharpedges,responsibleformarkingordirect metal-
to-metalcontactwithpanels,inordertoavoidbody corrosion;
3. featuring preloaded elastic fasteners with additional semistructural
adhesive, when required in order to avoid beating and vibrations
whiletraveling.
Sometimes, moldings are fitted by bonding only; in this case, bi-
adhesivesareusedoverall,with some additionalsemistructural bonding,
preferably at eachmolding end, to fix the molding while curing and to
avoid peeling , themostcriticaltype of stressfor adhesives.Anywayit is
recommendedtoaddmechanicalfastenersat bothmolding ends.

121
e. Spoilers
On bumpers, some front spoilers, fully integrated in the car
frontend,havebeen shown.
Rearspoilersarenotusuallyintegrated withbodyparts, unless
small size and their shape allows integration; usually rear
spoilers are add-on devices, fitted to the body mainly for
aerodynamicpurposes.
In many cases, mostly when mounted at the rear end of the
roof orontheliftgateuppercross-member
,the aerodynamics
tas
kismixedwiththeintention to createa sporty imageand
therequirementtoprotectrearpassenger areafromsunrays.

122
e. Spoilers
Specificationsanddeliverytests
Inadditiontothelegalrequirementsconcerningtheoutersurface shape
(minimumradius2.5mm)andtheusualenvironmentresistance of plastic
components,spoilersmustcomplywith anumberof performancecriteria
typicalfortheirmission,including:
contributionto flexibility;
1. Overallresistancetomaximumdynamicloads;
2. Attac
hment s
tiffnes
s
, inc
luding supporting metal s
heets
3. Yieldstrengthandfatigueresistanceoffastenersinrepeated decklid
ortailgateoperations;
4. Geometricalbodyfittingqualityincontact areas;
5. Absenceofpermanentmarkordeformationincontactareas;
6. Resistanceindecklidmisusetesting;
7. Absenceofbeatsandvibrationsonroughroads.

Body Components
123
2. WeatherStrips
a. MissionandDeliveryCriteria
b. DoorWeather Strips
c. LiftgateandT
runkLidWeather
Strips
d. Hood Seals
e. OpeningRoof Seals
f. GlassSeals
3. GlassandMirrors
4. MovableParts
5. Windshield Wiper
6. V

Body Components
124
2. WeatherStrips
3. GlassandMirrors
a. Windshield
b. Door Windows
c. QuarterGlass
d
. B
a
c
kWindow
e. ExternalMirrors
f. InsideMirrors
4. MovableParts
5. Windshield Wiper
6. V
ehic
leLightingandSignalling

Body Components
125
2. WeatherStrips
3. GlassandMirrors
4. MovableParts
a. SideDoors
b. SlidingDoors
c. T
runkLid,Liftgate,T
ailgate
d
. T
wi
nRearDoors
e. Hood
f. Sunroofs
g. WindowGlassRegulators
5. Windshield Wiper
6. V

Body Interiors
126
1. RestraintSystems
2. Dashboard
3. InteriorT
rims
4. Sea
ts
5. AirConditioning

Body Interiors
127
1. RestraintSystems
a. SafetyBelts
i. GeneralIssues
ii. SeatBeltAnchorages
iii. AnalysisofSeatBeltsComponents
b. Air-Bag
i. GeneralIssues
ii. Componentsof theAir-BagSystem
iii. Air-Bag Typologies
iv. SimulationModel
2. Dashboard
3. InteriorT
r
i
m
s
4. Sea
ts
5. Air Conditioning

Body Interiors
128
1. RestraintSystems
2. Dashboard
a. Cockpit
b. Dashboard
c. Console
3. InteriorT
rims
4. Sea
ts
5. AirConditioning

Body Interiors
129
1. RestraintSystems
2. Dashboard
3. Interior T
rims
a. PillarsandInteriorV
alencePanels
b. Door Panels
c. Parcel-T
rays
d. Headliners
4. Sea
ts
5. AirConditioning

Body Interiors
130
1. RestraintSystems
2. Dashboard
3. InteriorT
rims
4. Sea
ts
a. FrontSea
ts
b. RearSea
ts
c. ChildSea
ts
5. AirConditioning

Body Interiors
131
1. RestraintSystems
2. Dashboard
3. InteriorT
rims
4. Sea
ts
5. AirConditioning
a. Heater
b. ControlGroups
c. AirConditioning
d. AirDistributionintheCockpit
e. DesignCriteria
f. InnovativeT
rends

To be continued… … …
132

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