Class 3 Vehicles

8/20/2019 Class 3 Vehicles

1/60

Highway Design

Class 3

Vehicles

1


2/60

From Last Time

• Purchase book

• Lecture – History

– Finance overview

• Housekeeping – mails! Course " in #ub$ect Line

• %& 'C(VL )1* +uestion on Homework,

• Homework 1 – Due -*.-1.*-1/ 0Toay2

*


3/60

oa e c ePer4ormance• 5hy is vehicle

per4ormanceimportant6 – Determines all highway

esign an tra7coperations

– De8nes howtransportation engineersmust react to avancingvehicle technologies

– The single most

important 4actor ine8ning the traeo9between mobility0spee2 an sa4ety

3


4/60

Vehicle Per4ormance

Vehicle Capabilities

• :cceleration

• ;reaking

• :ccienteconstruction

• nviro (mpacts – missions

– Fuel

–


5/60

Vehicle Per4ormance

Driver Capabilities

• perception.reaction times

• eyesight0peripheralrange= heightabove roaway2


6/60

:cceleration

• Case o4 constant Power

• 5here t = time

•

Where f = force and x = distance

• Where v = velocity

•

/


7/60

:cceleration

• #pee vs Time

?

v

t

Constant Acceleration

Falling objectv

t

Constant Power Vehicles

• Distance vs Time

x

t

Constant Acceleration

Falling object

x

t

Constant Power Vehicles


8/60

60

30

:cceleration

• #pee vs Distance


9/60

:cceleration= Velocity= Distance

v f = v 0 + at

d = v 0t +

(!at "

v f " = v 0

" +

"adv f = final velocity, ft/sec

v0 = initial velocity, ft/seca = acceleration or deceleration, ft/sec2

t = time, sec

d = distance, ft

where


10/60

esistance Forces

1& :ir

*& (nertial

3& @rae

)& olling

A& Curve


11/60

1& :ir esistance

Fa = 0.5 x Cρ

x A

x ( ρ

xv

2

!

C# B rag coe7cient 0-&) -&2

A B 4rontal cross sectional area 04t*2

E B air ensity 0lb.4t32 0-&-?2

v B vehicle velocity 04t.sec )


12/60

Coe7cient o4 Drag CD

1*

• Volkswagen L1 B0.189

• @G V1 B 0.195


13/60

*& (nertial esistance

Fi = m x a = (w/g) x a

w B weight 0lbs2

$ B 3*&* 04t.sec*2

a B accel 04t.sec* )

Force to accelerate


14/60

3& @rae esistance

Fg = m x g x sin Ө

ӨӨ

Fg


15/60

Fg = m x g x sin Ө

23o

Ө

Fg

w = 2.6 Tons

3& @rae esistance


16/60

23o

Fg =

2000 #

w = 5200 # 5

1213

Fg = m x g x sin Ө

3& @rae esistance


17/60

Fg = m x g x sin Ө

23o

Ө

Fg = 2000 #

w = 5200 #

3& @rae esistance


18/60

Fg = m x g x sin Ө

23o

Ө

Fg = 2000 #

w = 5200 #

3& @rae esistance


19/60

Fg = m x g x sin Ө

6o6

Fgw = 2.6 Tons

10

1

3& @rae esistance


20/60

6o

Fg

≈

520 #

w = 5200 # 1.04

9.9410

f t!e angleis small,

"in ≈ Tan

3& @rae esistance


21/60

)& olling esistance

F r

• F r = x w

$rder of magnit%de& '0 l(s/ton

-I Tire e4ormation1-I Gechanical parts


22/60

3& J )& olling an @raeesist&•

(4 a vehicle is on a hill= the graeresistance will ten to make it rollownhill

• The rolling resistance will ten tokeep the vehicle 4rom rolling ownhill

• :lthough it is goo to know thevehicle weight= the weight is notnecessary to solve these types o4problems because mass isproportional to weight&


23/60

• #ay a concrete truck is parke on a

hill an assume it weighs A tons&:ssume the rolling resistance is A-lbs per ton& :ssume the hill is a 3I

grae 03 vertical per 1-- horiKontal2&nce the parking brake 4ails= how4ast will the truck be rolling own thehill in 1- secons6

3& J )& olling an @raeesist&


24/60

)*

)

100



25/60

)*

)100

1 0 0. 0 + 5

10,000.00 #

,5.50 #

2.-'#

&

)

100

)

1 0 0

1 0 0 .

0 + 5



26/60

)*

)100

1 0 0. 0 + 5

,5.50 #

50#x 3,5.50#/2000#/ton4

= 2+.-#

$&



27/60

)*

)100

1 0 0. 0 + 5

,5.50 #

2+.-#

$ 7

F8T$&

2.-'

49.98#



28/60

F = m x a

F = m x a = (w/g) a = 49.98#

F = (10,000/32.2) a = 49.98# a = 49.98 (32.2/10,000)=0.161ft/sec2

Afte 10 sec!"s, v = 1.61 ft/sec(1.08 m$%)

&ist = ' a t 2 = (.)(0.161) (100) =8.0 feet



29/60

A& Curve esistance

F = m x aFc = m x ac = (w/g) x v

2 /(2

x )

V B spee 0velocity2

04t.sec2w B weight 0lbs2$ B 3*&* 04t.sec*2

a B accel 04t.sec* )

V

F


30/60

Power an Force eMuirements

v B spee 0velocity2

04t.sec2% B sum o4 resistances0lbs2

B∑ & a '& i = & $ = & r = & c


31/60

Tractive 9ortN Coe7cient o4 :hesion

• Tractive 9ort 02 – Force reMuire to overcome esistance

• Ga%imum tractive e9ort available 4rom roa sur4ace

• B coe7cient o4 roa ahesion

– Ga% F 4or 4ront an rear wheel rive vehicles• #um moments about the 4ront an rear a%le

•

31

coefcient o roadadhesion

Pavement Ma

!lide

@oo an ry 1&-- -&-

@oo an wet -&- -&/-

Poor an ry -&- -&AA

Poor an wet -&/- -&3-

Packesnow.ice

-&*A -&1-

V l it : l ti


32/60

Velocity an :cceleration

v f = v 0 + at

d = v 0t +

(!at "

v f " = v 0

" +

"ad9e!icle acceleration 3ft/sec24

8ar 10

:i;


33/60

1& Visual 0sight2

2. >inest!etic 3movement4

). 9esti(%lar 3e?%ili(ri%m4

+. %ditory 3!earing4

The #ensory Process

Driver Characteristics

i h i i


34/60

Perception eaction Time

The intervalbetween seeing=

4eeling= or hearinga tra7csituationO

an making aninitial response towhat has beenperceive&


D i Ch i i


35/60

Perception eaction! ) 'Points,

1& Detection

*& (enti8cation3& Decision

)& esponse


D i Ch i i


36/60

Perception eaction

• Detection something enters the8el o4 vision

• (enti8cation #u7cientin4ormation is collecte to make aecision

• Decision 5hat action to take• esponse :ction carrie out



37/60

Critical Distances

#ight Distance! The length o4 highway visibleahea to the river o4 a vehicle&


38/60

#ight Distances

• #topping #ightDistance

• Passing #ightDistance

• Comple% Locations

Decision #ightDistance


39/60

#ight Distances

• #topping #ightDistance

• Passing #ightDistance

• Comple% Locations

Decision #ightDistance


40/60

#topping #ight Distance

he minim)m distancere*)ired to stop a vehicle

travelin$ near the desi$nspeed' before it reaches astationary obect in thevehicle,s path


41/60


• ;rake eactionDistance

• ;raking Distance


42/60

#topping #ight• ;rake eaction Distance

– v-tr B 1&)? v-tr

• ;raking Distance

– v*.0*a2 B 1&-?A v*.0*a2

• #toppings '#a4e, #topping Distance

0##D2

– ##D B v-tr v*.0*a2

– here 'a, is eceleration

• a B 'see ne%t slie,

Equationstranslate mph

into feet

i i h


43/60

#topping #ight• #toppings '#a4e, #topping Distance

0##D2 – ##D B v-tr v*.0*a2

–

• -&) Gost car companies guarantee

• -& -& high per4ormance

•

:ccient econstruction


44/60

:ccient econstruction

– :verage! -& secons – Very goo! -&/ secons

– Qse 4or esign! *&A secons

•

))


45/60

#topping Distance R Flat

Source: AASHT


46/60

#topping Distance R @rae

! mph" d is feet" # e$pressed in percent"

%f a &' up(rade) # would *e &"

Source: AASHT


47/60

#topping Distance R @rae

Source: AASHT

#topping Distance S #topping #ight


48/60

#topping Distance S #topping #ightDistance

-o) not only have to stop' yo) have to stop beca)se yo) noticed somethin$.


49/60


Driver = 3.5 feet above pavement

Object = 2.0 feet above pavement


50/60


+ is called the +iddle rdinate


51/60


Vehicle Types


52/60

#impleClassi8cation

• Cars• ;uses

• Trucks

• ecreationalVehicles

Vehicle Types

Vehicle Types


53/60

DetaileClassi8cation

• Cars – Cars

– Vans

– #QVs

• ;uses – GiniRbus

– CityRbus

– #uburban ;us

– :rticulate ;us

• ecreationalVehicles

etailed 8lassification• Tr%c@s

– "ingle Anit 3"A4

– "emi;Trailer 3B4

Vehicle Types

D i V hi l Di i


54/60

Design Vehicle Dimensions


55/60

Design Vehicle Properties

i i


56/60

Turning Properties 5;R)-

T i P i 5; )-


57/60


esigning a 8%r(

T i P i 5; )-


58/60


T i P ti 5; )-


59/60


T i P ti 5; )-


60/60


Date post:	07-Aug-2018
Category:	Documents
Upload:	stelios
View:	214 times
Download:	0 times

Class 3 Vehicles

Documents