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Bureau of Mines Report of Investigations/1987

Extended Bumper Designs for Large Haulage Trucks

By Stephen A. Swan

UNITED STATES DEPARTMENT OF THE INTERIOR

Report of Investigations 9089

Extended Bumper Designs for Large Haulage Trucks

By Stephen A . Swan

UNITED STATES DEPARTMENT OF THE INTERIOR Donald Paul Hodel. Secretary

BUREAU OF MINES Robert C. Horton, Director

Library of Congress Cataloging in Publication Data:

Swan, Stephen A. E xtended bumper designs for large haulage trucks.

(Bureau of Mines report of investigations; 9089)

Bibliography.

Supt. of Docs. no .. I 28.23; 9089.

1. Dump trucks - Bumpers - Design and construction. l. Title. II. Series: Report of in­vestigations (United States. Bureau of Mines) ; 9089.

TN23 .U43 [TL230] 622 s [622.2'76] 86-607929

CONTENTS

Abstract........................................................................ 1 Introduction.................................................................... 2 Critical physical dimensions.............................. ....... ............... 5 Dynamics of rear-end collisions................................................. 6 Design criteria................................................................. 7 Collision dynamics.............................................................. 8 Impact forces................................................................... 14 Specifications.................................................................. 15

Euclid R-170 ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• " _. 15 Titan 33-1SB.................................................................. 15 Unit Rig Mark 36.............................................................. 15 WABCO 17 OC. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 15

Summary .••••••••.•.••••••••.•••••••••••.•••••••••••••••.•••••••••••••• II......... 16 Appendix A.--Extended bumper design for Euclid 170-st-capacity truck............ 17 Appendix B.--Extended bumper design for Terex 170-st-capacity truck ••••••••••••• 20 Appendix C.--Extended -bumper design for Unit Rig 170-st-capacity truck.......... 23 Appendix D.--Extended bumper design for WABCO 170-st-capacity truck ••••••••••••• 26

ILLUSTRATIONS

1. Schematic of rear-end collision........................................... 2 2. Cab location versus rear bed height....................................... 2 3. Truck collision, cab penetration.......................................... 3 4. Truck collision, actual................................................... 4 5. Extended bumper design concept............................................ 4 6. Extended bumper with improved ladder system............................... 4 7. Extended bumper with modified ladder system............................... 5 8. Critical truck dimensions................................................. 6 9. Rear-end impact at 15° angle, bumper misses tire.......................... 8

10. Rear-end impact at 15° angle, bumper hits tire............................ 8 11. Load-deflection curve for tires used on 170-st-capacity haul trucks....... 9 12. Schematic of impact dynamics •••••••••••••••••••••••••••••••••••••••••••••• 11 13. Tire deflection and sliding distances versus energy absorbed.............. 12 14. Impact velocity to deflect tires to maximum limit for given tire inflation

15. 16.

A-I. B-1. C-1. 0-1.

pressure................................................................. 13 Maximum bumper force developed versus tire inflation pressure ••••••••••••• Impact velocity versus resulting bumper force ••••••••••••••••••••••••••••• Extended bumper design for Euclid 170-st-capacity truck ••••••••••••••••••• Extended bumper design for Terex 170-st-capacity truck •••••••••••••••••••• Extended bumper design for Unit Rig 170-st-capacity truck ••••••••••••••••• Extended bumper design for WABCO IJO-st-capacity truck ••••••••••••••••••••

TABLE

13 14 17 20 23 26

1. Road adhesion coefficients for different surfaces ••••••••••••••••••••••••• 10

UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT

ft foot Ibf pound (force)

f t/s foot per second Ibf/ft pound (force) per foot

f t °lb foot pound mph mile per hour

in inch pct percent

ksi kips per square inch psi pound per inch

Ib pound st short ton

EXTENDED BUMPER DESIGNS FOR LARGE HAULAGE TRUCKS

By Stephen A. Swan1

ABSTRACT

This Bureau of Mines report discusses research to analyze and evaluate extended bumper systems in order to determine the degree of protection provided to equipment operators in the event of rear-end collisions be­tween off-road rear-dump haulage trucks. The basic characteristics of rear-end collisions were determined, and a detailed analysis of the col­lision dynamics was performed to identify the magnitude and direction of impact loads, the amount of energy that must be absorbed during impact, and the major factors that affect the outcome of a collision. Separate bumper designs were developed to facilitate attachment to four 170-st­capacity haulage truck frame types.

1Mining engineer, Twin Cities Research Center, Bureau of ~1ines, Minneapolis, MN.

2

INTRODUCTION

The extended bumper was developed to provide protection to the operator in the event of a rear-end collision between trucks. This protection is necessary be­cause the outcome of a rear-end collision between trucks often results in the rear­end of the dump body of the forward truck penetrating the cab area of the rearward t ruck (fig. 1), causing operator injury, as well as extensive machine damage. Figure 2 shows the relationship of the height of the rear of the dump body in relation to the top of the cab and opera­tor's platform for various truck models. This indicates that for most truck combi­nations, the height of the dump body is

at a level to penetrate the cab area. Figures 3 and 4 show the results of truck collisions in which the dump bed pene­trated the cab area of another truck, in each case, causing serious injury to the operator and major truck damage. The goal of this program was to design a bumper extending far enough in front of the existing bumper to prevent any intru­sion of a dump bed of one truck into the operator's cab of another truck during a collision.

To achieve this goal, one solution was to design an energy-absorbing system, similar to an automotive bumper system. This approach would be acceptable, but

FIGURE 1.-Schematic of rear·end collision.

25 ,-----,------.-----,------,-----,------,-----,------,-----,------,-----,------,

~ 20

cl Top of cab

z ::J 0 n:: (:J

w 15 > 0 m « l-I ---(:J

10 w I

Platform

5 0 2 4 6 8 10 12 14 16 18 20 22 24

REAR-DUMP HAULAGE TRUCK MODELS~ 100 st

FIGURE 2.-Cab location versus rear bed height.

3

FIGURE 3.-Truck collision, cab penetration.

would necessitate extensive laboratory testing to design and refine the system. Therefore, the approach used was to design a bUmper long enough to prevent any intrusion into the cab area, wide enough to impact a minimum of two rear tires, and high enough above the ground to impact near the centerline of the tires. The bumper had to be designed to structurally carry the impact loads, with the energy being absorbed by the rear tires of the contact vehicle.

The bumper installation depicted in figure 5 is typical of extended bumpers presently in use. The bumper is equipped with headlighrs, clearance lights, wheel

chocks, and an automatic engine kill switch; a fire extinguisher and a fire suppression switch are located near the ladder for use in emergencies.

Previous research had identified truck ladders both as having high maintenance costs and as a major cause of injuries. One method for reducing these injuries would be to install a staircase-type lad­der on the front of the truck. This would normally result in increased main­tenance requirements since this type of ladder would be more susceptible to dam­age; but with an extended bumper, a staircase ladder could be installed, as in figure 6, without increasing the

4

Wheel chock s

FIGURE 4.-Truck collision, actual.

Emergency engine kill switch

FIGURE S.-Extended bumper design concept. FIGURE S.-Extended bumper with Improved ladder system.

-

maintenance requirements. In fact, the maintenance requirements may be reduced when compared with requirements of a con­ventional ladder, which is outside the zone protected by the bumper. One prob­lem with the staircase ladder is that anyone climbing up the ladder is not vis­ible to the operator (fig. 6). With the extended bumper this problem can be elim­inated, as illustrated in figure 7, since anyone getting on the truck steps upon the bumper from the driver's side of the truck and traverses the front of the bumper in order to go up the staircase ladder.

This study was performed by Woodward Associates, Inc., San Diego, CA, under a Bureau of Mines research and development contract. 2

~ Centrol

Fire ext I ngu isher

Fire suppression switch

Emergency engine kill switch

FIGURE 7.-Extended bumper with modified ladder system.

5

CRITICAL PHYSICAL DIMENSIONS

In order to ensure that the bumper meets the basic criteria of impacting the rear tires of a truck and preventing the dump bed from penetrating the cab area, it was necessary to determine the physi­cal dimensions of the truck and bumper.

As shown in figure 1, the rear-end of the dump body for most haulage trucks over 100 st is at a height that would impact the cab on another truck. There­fore, it was necessary to obtain the physical dimensions to ensure the crite­ria were met. These dimensions included (fig. 8):

x = distance from the existing bumper to cab,

y' distance from rear tire to end of dump body,

r = loaded tire radius,

z = height to top of existing bumper,

z' height to bottom of existing bumper,

2Dahle, J. L., L. Owens, and G. E. Adkins. Design of an Extended Bumper for Mine Haulage Trucks (contract J0215003, Woodward Assoc., Inc.). BuMines OFR 123-83, 1981, 88 pp.i NTIS PB 83-221515.

and

d distance between inner rear wheels.

These dimensions were used to deter­mine the following extended bumper configuration:

Overall extended bumper length, L, is defined by L > (y' + tire deflection + bumper deflection) - x.

The overall extended bumper to impact two rear tires is W > d + 2 (tire width).

width, W, defined by

The height of the bumper, H, should be H '" r.

Since one of the requirements was to minimize damage to the extended bumper during impact, it was necessary to deter­mine the tire deflection available for 170-st-capacity haul trucks before any suspension component is impacted. The WABeO, Unit Rig, and Euclid trucks have 18 in of tire deflection available to absorb the impact energy before a suspension component would be impacted. However, the Terex 170-st-capacity haul­age truck has suspension components rear­ward of the rear tires. Therefore, the

6

Left side ~

! I I I f-I I r - - --:

L _ .!... _ _ _ _ ..1. _ _ ~

r - +--- - -r- - l I I

r : I I I I Cab I I I I I I I L __ __ I r- k -0: --- - ~ __ J

I I

d I : L 1 I 0 1 1 ~ -'- _____ 1 _ _ -I I I ; I 1 1 I I L L -l __ -_-.:-=±::.~ I 1 I 1 I 1 I I I -

c~ Right side

Ys --" A

Y ------

B c FIGURE B.-Critical truck dimensions.

bumper designs may not be effective when impacting a Terex truck.

The dimensions of the extended bumper for 170-st trucks are as follows:

L = 4 ft,

and

w 13 ft,

H 4.5 to 5.5 ft.

DYNAMICS OF REAR-END COLLISIONS

For the purpose of analysis, three dif­ferent impact configurations were con­sidered for the design of an extended bumper. These cases were chosen to en­sure structural integrity for a wide range of loading conditions:

Case 1: Direct rear-end collision.-­The longitudinal centerlines of the two trucks are in line, resulting in a sym­metric end loading of the bumper. The extended bumper impacts the inner left and right rear tires.

Case 2: Offset rear-end collision.-­The extended bumper impacts one set of dual rear wheels.

Case 3: Angle impact.--One tire is im­pacted by one corner " of the extended bumper, causing a side load on the bumper as well as a front and vertical load.

A dynamic analysis was conducted to determine the load magnitudes for the three impact conditions. Since most impacts are relatively low speed, the

I

f "

impact loads on an extended bumper were determined as follows:

Case 1--Impact velocity 5 mph.

Case 2--Impact ve loci ty 5 mph.

Case 3--Impact velocity 3 mph.

Another factor that influenced the as­sumed speed at impact was that the extended bumper must be weaker than the truck frames in order to minimize frame damage; the velocity for case 3 is lower since the bumper may only impact one tire, limiting the amount of impact energy absorbed.

Design for high-speed collisions will substantially increase the bumper weight, resulting in potential frame fatigue dam­age. A sensitivity analysis is needed to determine the optimum tradeoff point of bumper weight versus frame damage from both frame fatigue and ultimate strength standpoints.

The dynamic analysis assumes the worst case of two of the heaviest 170-st­capacity trucks impacting when both are fully loaded. The following is a summary of the factors included in the dynamic analysis:

7

Truck weights of 575,000 lb each.

Rotational inertia, 15 pct.

Actual load deflection characteristics of tires used on 170-st-capacity haulage trucks (36 by 51 type E-3 or E-4).

Assumed tire pressure of 75 psi.

Conservative value for a road adhesion coefficient (0.85), resulting in higher bumper forces before a machine may slide on the ground.

Truck frame capability.

Impact velocity (3-5 mph).

The analysis results in the following governing impact loads for extended bump­ers in the three loading cases, in pounds:

Cases 1 and 2: Front load •.•••••••••••••••• Vertical load •••••••••••••••

Case 3: Front load ••.••••••••••••••• Vertical load ••••••••••••••• Side load ••••.••••••••••••••

640,000 38,400

280,000 16,800 75,000

DESIGN CRITERIA

There are two primary causes of rear­end collisions between haulage trucks: (1) loss of control and (2) poor visibil­ity or not seeing the other truck and therefore backing into it. Collisions resulting from these two causes have dif­ferent characteristics with regard to the type of protection required to prevent penetration of the dump body into the cab.

The loss of control accidents are the result of mechanical failure in either the retarding or braking system. There­fore, the collisions may involve a sub­stantial speed differential between the two trucks. This type of collision usu­ally results in large amounts of tire de­flection; the bumper must extend far enough forward to prevent the dump body

from entering the cab with the maximum amount of tire deflection.

The poor visibility accidents are usu­ally low speed (under 3 mph) and oc­cur while the truck is maneuvering in congested areas, such as near shovel or dump sites. These collisions create another bumper design problem, in that quite often two trucks are at an angle to each other. It would not be practical to have a bumper that would eliminate all of the hazards from this type of collision, because the bumper would have to be wider than the truck. In addition, this type of collision also produces significant side loads that the bumper must withstand.

It is important to note that the amount of protection provided by any given

8

Left rear duals just miss bumper

Left side

15°

U======================:;:=:j====:::f::=-____ ~* 8 = 15° Right side

FIGURF: 9.-Rear·end impact at 15° angle, bumper misses tire.

~-----,

I I I I I I I I L ____ J

FIGURE 10.-Rear·end impact at 15° angle, bumper hits tire.

bumper is dependent on the trucks and the way tires hit the bumper. figure 9, a collision rear wheels just miss

the angle between in which the rear As illustrated in in which the left

allow the However, tire, the (fig. 10).

dump if the

dump

body to hit the cab. bumper hits the left

body would miss the cab

the bumper can

COLLISION DYNAMICS

The maximum strength of any bumper is limited by the strength of the frame. However, the bUmper must be sufficiently strong to survive a collision between two trucks at a given speed. While the analysis of the forces generated in a collision between two trucks is extremely

complex, certain assumptions can be in order to determine the maximum an extended bumper must support. assumptions include the following:

made forces

These

The truck frame is rigid and the bumper will fail before the frame is bent.

The bumper will only make contact on the rear tires of the other truck.

All of the energy is either absorbed by the tires or dissipated by moving the other truck.

The rotating inertia due to the mass of the rotating components of a moving truck is 15 pet of its kinetic energy.

In addition to these assumptions, there are several critical factors that must be determined in order to analyze the bumper loads including the following:

K deflection rate of the tires,

U the road adhesion coefficient between the trucks tires and the ground,

X max the maximum tires before

deflection a solid

the truck is impacted,

of the part of

and

9

N number of tires impacted,

~ angle of impact between the trucks.

Since most 170-st-capacity trucks are equipped with 36- by 51-in type E-3 or E-4 tires, the load deflection rate for a given tire is dependent on the manufac­turer, type of construction, and the air pressure. However, since these tires must be able to support the same load without overheating, the load deflection rates of the various tires are similar. As shown in figure 11, the load­deflection curve for a typical 36- by 51-in tire, the rate is a linear function highly dependent on air pressure. The effect on the bumper design is to in­crease the forces as air pressure is increased and the tire becomes harder. If the air pressure is low enough to cause the bumper to strike the rear

20 .-------,--------,-------,--------,--------,-------,,-------,-------,

14

c

12 z o ~

~ 10 -.J u.. W o

8

6

4

2

o

45 psi 75 psi 100 psi

50 100 150 200 250 300 350 400 TIRE LOAD, 103 'b

FIGURE 11.-Load·deflection curve for tires used on 170·st capacity haul trucks.

10

cause the bumper to strike the rear sus­pension of the truck, the forces on the the bumper will be higher.

The road adhesion coefficient is a mea­sure of the ability of the tires to grab or adhere to the road surface. As the coefficient is increased the force required to make a stationary truck slide increases. As shown in table 1, the road adhesion coefficient is dependent on the type and condition of the road surface.

Except for the Terex 33-15B, the rear tires of haulage trucks extend beyond the frame and rear suspension members. The distance from the back edge of the tire to the rear suspension struts is approxi­mately 18 in on all of the other 170-st­capacity trucks. On the Terex truck both the suspension struts and the rear-end housing extend beyond the rear edge of the tires. In certain cases where the trucks are misaligned it is possible to deflect the tires to the rim, or approxi­mately 30 in.

The angle of impact is an important de­sign factor because, as the angle in­creases, the side loads increase and the amount of protection to the operator will decrease. This angle is a matter of cir­cumstances under which one operator does not see the other truck and backs into it. It is felt that if the angle between the two trucks is such that if any part of the second truck, from the center of the rear tires forward, is visible in the mirror of the truck backing up, then

TABLE 1. - Road adhesion coefficients for different surfaces

Gravel: Packed and oiled •••••••••••• Lo os e ••••••••••••••••••••••• We t ••••••.••..•.•....••••...

Rock: Crushed .••..•.....••••....•. We t ...........•........•....

Earth: Fi rm •••••••.•••••••••••••••• Loose ••••••••••••••••••••••• We t •••••••••••••••••••••••.•

Clay loam: Dry •••..•.••.••.•.•••••.•.•• Ru t ted •••••••••••••••••••••• We t •.......••......•...•...•

0.55-0.S5 .40- .70 • 40- • SO

.55- .75 • 55- .75

.55- .70

.40- .60

.40- .55

.50- .SO

.15- .50

.15- .45

there should be no collision. At this angle of approximately 15° or sharper, an operator should be able to see a second truck in the rearview mirror.

Since both the force required to slide a stationary truck and the energy of a moving truck increase as the weight of the trucks increases, the worst case col­lision is where a loaded truck runs into another loaded truck that is parked with its brakes applied. In order to complete the dynamic analysis of the maximum forces generated during a collision be­tween two trucks, it is assumed that the energy of the moving truck is conserved. This is the case when there is no bending or breaking of components on either truck.

Since energy is conserved, the initial energy of the moving truck is equal to the combined energy of the two trucks at any given time, plus the energy dissi­pated in the rear tires of the second truck, plus the energy expended in the moving of the second truck.

The following can be used to express the energies:

Energy of the first truck

before impact = 1/2M lV~.

Energy of the first truck

after impact = 1/2M1Vf.

Energy of the second truck

after impact = 1/2M2V~.

Energy dissipated by moving

second truck = FfY •

Energy dissipated into

rear tires = 1/2KX2 •

These terms are combined to write the following equation:

(1)

where H,

Vo

V,

y

K

and x

effective mass of truck 1,

effective mass of truck 2,

initial velocity of truck 1, f t/s,

velocity of truck 1 at any gi ven time after impact f t/s,

velocity of truck 2 at any given time after impact, ft/s,

weight of truck, lb, times road adhesion coefficient (frictional force, lbf)

displacement of truck 2, ft,

deflection rate of tires, lbf/ft,

distance tires deflect, ft.

Truck 2, M2

11

Figure 12 shows a schematic of the impact dynamics.

There are four basic steps in a typical rear-end collision for which this equa­tion applies:

1. Tire just before impact with truck at a given weight and velocity. 2. Time after impact with truck 2

still stationary with an increasing amount of rear tire deflection.

3. Time after impact with truck 2 sliding on road with a given adhesion coefficient and an increasing amount of rear tire deflection.

4. Time after impact when both trucks come to rest.

For the case that both trucks are of equal weight M, = M2 = M and M = (weight of truck/gravity) (rotational constant), where the rotational constant is due to mass of rotating parts = 1.15.

Truck I, MI

-----);.Ff

KEY K=tire stiffness

x = tire deflection

Y=distance truck 2 slides

Ff : frictional force

Va: impact velocity

FIGURE 12.-Schematlc of Impact dynamics.

12

The equation is written as follows:

1/2 KX2 = 1/2 MV~

- [1/ 2M (V T + V ~) + F f Y 1 • (2 )

When the trucks have come to rest, V, = V2 0, and the equation can be written as:

1/2 KX2 1/2 MV~ - FfY. (3)

Since the total energy of the system is simply the kinetic energy of truck 1 be­fore impact, the following equation holds true:

Etot = 1/2 MV~. (4 )

Equation 3 may be rewritten as follows to find the displacement of truck 2 if X and E totals are known:

Y (5)

320 .0 , ....

'" Truck Q displacement (Y) ~ 240 <.!)

0:: W Z W

-.J <!

160 f-a f-

80

0 2 3 4 5 6 7 8 9 10

Also, the following relationship between X and Y holds true:

Y = X - X 0, (6)

where X is the deflection required for truck 2 to start slide, which is 0 deter­mined with the following equation:

Xo = F t/K.

For the case of maximum tire deflection the total energy of the system can be determined for any given tire pressure using the following equation:

Etot = Ft(X - Xo) + 1/2 KX2. (7)

Figure 13 shows the relationship of the energy that is absorbed by the tire de­flecting and the machine sliding on the

II 12 13 14 15 16 17 18 TIRE DEFLECTION, in

Y 0 2 3 4 5 6

DISPLACEMENT OF TRUCK, in

FIGURE 13.-Tire deflection and sliding distances versus energy absorbed.

fl .'

13

7 ,--------r--------r--------,--------r--------,--------,--------,--------,--------,

J:: a. E

~ f-

<..> 0 --1 W > ::.:: <..> ~ a:: f-

6

5

4

3 35 40 50 60 70 75 80 90 100

TIRE PRESSURE, ps i

FIGURE 14.-lmpact velocity to deflect tires to maximum limit for a given tire Inflation pressure (two tires impacted).

800

720

:E: 640 "'0 w <..> a:: o I..L. 560

480

400 35 43 51 59 67 75 83 91 99

TI RE PRESSURE, psi

FIGURE 15.-Maximum bumper force developed versus tire Inflation pressure (two tires Impacted).

110

107

14

ground. The of truck I, which will deflect the tires to the maximum limit before any metal contact occurs be­tween the two trucks, can be determined with the following equation:

v (8)

Figure 14 shows the ve of truck 1 to deflect two rear tires to the maximum limit as a function of tire air pressure for the case of the heaviest 170-st­

truck, which has a gross vehicle of 575,000 lb and the t road

coefficient (from table 1) of 0.85.

IMPACT FORCES

The horizontal force on the bumper at any given time is described as follows:

KX, (9 )

where Fb force on bumper, lb,

K deflection rate of tires,

and x deflection of tires.

5

4

-C. a. E

3 .;.: f--

0 0 ..J W > :::.::. 2 0 ::l 0::: f--

a lOa 200 300

re 15 shows the horizontal r force as a function of tire pressure for the case where the bumper impacts two tires. Figure 16 shows the horizontal force on the bumper as a function of velocity where the impacts two tires with a given air pressure. For the case where the collision occurs with the two trucks at an to each other, a side load is introduced onto the bumper.

400 500 600 700 FORCE ON BUMPER, Ib

FIGURE is.-lmpact velocity versus resulting bumper force.

For this type of collision the forces acting on the bumper can be broken down as Fb side = Fb sin ~ and, Fb front = Fb cosine~, where ~ is the angle between the trucks, degrees, and Fb is the force due to tire deflection.

Any vertical loads on the bumper are the result of the trucks being at an angle to each other or vertical misalign­ment between the bumper and the rear tires. As shown in figure 14, the only

15

bumper that would normally not make contact with the center of the rear tire is that of the Terex 33-15B, since the top of its bumper is 4 in lower than the center of the tire. This amount of misalignment will result in a verti­cal load of 6 pct of the frontal load. For a 640,000-lb frontal load, the ver­tical load due to misalignment is 38,400 lb.

SPECIFICATIONS

The main supports of the extended bump­er must line up directly with the frame rails of the truck. It is critical that the dimensions of the frame rails on any truck are known before an extended bumper can be designed.

EUCLID R-170

The frame rails on the Euclid consist of a 12-in-high by 10-in-wide fabricated box section. The top and bottom plates are 1 in, and the side plates 5/8 in. The frame is constructed of high-strength alloy steel with a yield stress of 100,000 psi. The distance between the inside edges of the frame is 92 in. The front edge of each frame rail flares into the bumper and is 2 ft wide at the rear of the bumper. The bumper consists of a box section 14 in high by 8-1/2 in wide.

In order to mount the extended bumper (appendix A) on the truck, the fropt and top of the existing bumper will have to be reinforced to prevent it from col­lapsing from the impact loads. This can be accomplished by using a plate to form a pad onto which the extended bumper main supports would be welded.

TITAN 33-15B

The frame rails on the Titan consist of a 20-in-high by 8-in-wide box section. The top and bottom plates are 1 in, and the side plates are 1/2 in. The distance between the inside edges of the frame rails are 68 in. The frame is con­structed using a medium-strength steel

alloy with a yield stress of 45,000 psi. The front bumper is bolted to the frame rails, so it can be removed when the power module is removed.

The original bumper will have to be re­inforced in order to install the extended bumper (appendix B). In addition, since the bumper must be removable, any acces­sories mounted on the bumper must be easily disconnected from the truck.

UNIT RIG MARK 36

The front rails on the Mark 36 consist of a tapered box section with a distance of 90 in between the inside edges. The front of the frame is 11 in high by 3 in wide, with 5/8-in top and bottom plates and 7/16-in side plates. The frame rails are constructed from 100,000-psi yield stress steel and form the outer sides of the front bumper. The bumper is fabri­cated from 1/4-in plate with the lower part supporting the steering pivots. Only minor reinforcement of the bumper is required to mount the extended bumper (appendix C), since the frame rails ex­tend to the front of the bumper.

WABCO 170C

The WABCO frame consists of a box sec­tion 17 in high by 4-1/2 in wide with 1-1/2-in top and bottom plates and 5/8-in side plates. The distance between the frame rails is 57 in. The frame is con­structed of high-strength steel alloy with a yield stress of 100,000 psi. The front bumper is 1/4-in plate with a

16

removable section in the center for re­moving the power module. Only minor re­inforcement of the existing bumper is

required in order to mount the extended bumper (appendix D), since the frame rails extend to the front of the bumper.

SUMMARY

Bumpers based on the extended bumper designs developed will provide operator protection for rear-end collisions of 3 to 5 mph when installed on rear-end dump trucks. The use of such bumpers should reduce the extent of truck dam­age. Although the detailed designs in­cluded in the appendix are applicable to

170-st-capacity trucks, with minor mod­ifications, application on other sizes and models is possible. The major dif­ferences would be the spacing of the two main structural members in order to match the various frame widths. The bumpers' length, width, and height above ground would not vary.

~18'~

Di ITEM '-i 2. RE.O'D

APPENDIX A.--EXTENDED BUMPER DESIGN FOR EUCLID 170-st-CAPACITY TRUCK

ITEM 1 1 REQ'D

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NOTES,

156!i'

ITEM 5 ~ R E.G'D

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ZONE LT R ] DESCRIPTION I D.t. TEO 1 .... PPFlOVEO

!.------98'----1I-H-~"

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ITEM 6 1 REOD

ITEM 3 ::'REQ'D

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EXTE NDED BUMPE.R DE.SIGN FOR A h-'---l----'=--+-~~~=-------t--:::..::...___r'~+__+--__f E. UC LI D 170 TO N TRUe. K

I-~--l-~-----I-:~:"::"'><~~~~-'--'::.':~---J-:::':"::~---------l S'~ r~~D;~~TDR"'~~~~_ 201 SC>lE T ISHEET 1 OF '3

-

REVISIONS

I ZONE ILlR D'>' TE APPRO-..' f.O

NOTES,

~I+-' -----------/ HEMS

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L- - Db - ;qa - J - - -

( ) Zl 3 ' 3' IS 1'8 ;V8

FRm,lT ; [",:

P.~LEASE

SIZE ICODE IDEf'JT N0l DRA' .... 'NG NO.

1---------1 C I ~ iyg-201 SC ALE SHEET 20;= 3 ~

FIGURE A·1.-Extended bumper design for Euclid 170·st·capacity truck-Continued

l- _ - ----

NOTES,

CCNTR

DESIGNER

REVISIONS DESCRIPTION DATE APPRoveo

NOTES

& HEADLIGHTS TO BE MOUNTE.D BEHIND FRONT PLf\TE . LOC.ATION AND CUTOUT DETERMINED BY HARD\JARE AVAILABL E.

~ SIDE MARKER ;"IGHTS TO BE hOUNTED ON SIDE PLATES USING AVAILABLE. HARD\.JARE.

& PLATE TO BE WELDE..D USING 'N' FILLET.

o ITEM NO

I:::D<E:'::CK::::-+---f-___ -l EXTENDED BUMPER DESIGN FOR A r-L.~EN"':"'R:-+-t-----tEUCLID 170 TON TRUC.K.

RELEASE

DRAWINC NO.

~-------~C 1'-19-201

\HEET :> OF .3

FIGURE A-1 .-Extended bumper design for Euclid 170'st'capacity truck-Continued

ITEM 1 2 REQ'D

ITEM't 2. REO'D

BEND DOWN 30'

ITEM 8 ;:: REQ'D

APPENDIX B.--EXTENDED BUMPER DESIGN FOR TEREX 170-st-CAPACITY TRUCK

NOTeS,

f-I -----156"---- --1-16'1-[=-= =--=-=-=--=--=--=-=-- - =--=-=-=-~ - -=-=---~:..=..::..=--=--=-==-.------ -=--=-=-=..;--==-=..::I-~] JJl'

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ITEM 2 1 REQD

156"

I1EM 5 1 REO:D

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1-11--1{ I ~~

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ITEM 6 1 REO.'D

ZONE LTR

REvISIONS DESCRIPTION

ITEM 7 1 REQ'D

DA TE 1 APPROVED

SIZE rCDDe IDENT ND1 DRAWING HD.

~~~~~~~~~~~~~~~----------~ C ~ lyg-10c SCALE SHEET ~ OF 3

FIGURE S·1.-Extendell bumper design for Terex 170·st·capaclty truck.

-

-

N o

TOP V IE IN NOTES,

r*""1 - ----156"-------,'1

ITEM 9 1 REQ'D

REVISIONS

ZONE LTR DESCRIPTION

2SIDE5~ ~8 \ \

BOTTOM \flEW' ~ 2 SIDES II 3/8

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: :~ ITEM 1--+j: : I I I I

IL' Jf<' 0-----70'-' - ------o.J.J.'..JI'

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ITEM 10 1 REQ'D

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I DAT E I APPROVED

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Ic'-~T:'::. ';'=:N~=-R+---1f------f TEREY 170 TON TRUCK

SIZE rCODE IDENT 1'101 DRAWING HO.

1----------1 C 06491 ~ iw9 -102 SCALE SHEET 2 OF 3

FIGURE B·1.-Edended bumper design for Terex 170·st·capacity truck-Continued N

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-............ .... .............

I

.... ............... 1

NOTES,

2.

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I

REV ISIONS DeSCRI PTION n ..... TE ..... PPROVED

NOTES:

& HEADLIGHTS TO BE MOUNTE.D BEHIND FRONT PLATE LOCATION AND CUTOUT D[TERM~NED BY H,\RD'WARE AVA\ LARLE .

£ SIDE :'1A.RKER LIGHTS TO BE MOUNTED ON S:Q[ PLPT ES USING AVA.I L t:lBLE HARDVARE .

~A / ~ PLATE TO BE 'WELDED USING 'N' FILLET.

& MAY INSTALL ArTER ITEM::' IS IN PLAC.E .

o ITEM NO .

i?

80TH SIDES

- EXTENDED BUMPER DESIGN fOR A : TEREI<. 170 TON TRUCK

DR'-'NC NO.

1'1'3-102

SHE ET '> OF 3

FIGURE B-1_-Extended bumper deSign for Terex 170-st-capacity truck-Continued

N N

~ ~ ________________________ ~t~! __ ~ ______________ ~

APPENDIX C.--EXTENDED BUMPER DESIGN FOR UNIT RIG 170-st-CAPACITY TRUCK

(ZONE ClR(

NOTES,

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2 REQ'D

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DESCRIPTION I OA TE I APPROVED

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ITEM 6 1 REQD

ITEM 3 lREQ'O

E XTEND~O BUMPER DESIGN

f--------------lr--=--=:----t-:::-t--=-1~~~=t==+=====_=t "'OR A UNIT RIG 170 TON TRUCK

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ITEM 1

I REVISIONS IZONE LTR DESCRI PTION

NOTES,

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/A--'3Y-:y,-a"---<' ALL A.ROUND

FRONT VI~W

ITEM 7 1 REDD

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CCNTR

ORA.,.,

DESIGNER

I OATl I APPROVED

~C;;=~=Q('--+--I-----I EXTENDED BUMPER DESIGN FOR A ~L:..= . • :.::NGR"__t-+---_t UNIT RIG 170 TON T RUCK P.A.

RELEASE

SIZE !,CODE IDENT HOl DRA.WING HO.

~-------~ C ~ lY9-202 SCA.LE SHEET 2 Of 3

FIGURE C-1.-Extended bumper design for Unit Rig 170·st-capacity truck-Continued

1

NOTES,

C~TR

DESIGNER

REVISIONS

DESCRIPTION DA TE APPRovED

NOTES:

& HEADLIGHTS TO BE MOUNTED BEHIND FRONT PL,c"TE LOCATION AND CUTOUT DE.TERMINED BY HARD\JARE AVAILABL E.

~ SIDE. MARKE.R LIGHTS TO BE MOUNTtD ON SID[ PLi>.TES USING AVi>.ILIl.BLE HARD\JARE.

,&, PLATE TO BE WELDED USING W' FILLET.

o ITEM NO

)

/

i-=~;:=::'~+----j-----I EXTENDED BUMPER DESIGN FOR A rL"=.E=-NGR::-r--I-- ---t UNIT R:G 170 TON TRUCK

P.A .

RELEASE

DRAWING NO.

1--------1 C 1 '-1'3-202-~~--,.-L-----T.I~HE~ET~3~O~F73--1

FIGURE C-1.-Extended bumper design for Unit Rig 170·st·capacity truck-Continued N \J1

APPENDIX D.--EXTENDED BUMPER DESIGN FOR WABCO 170-st-CAPACITY TRUCK . -( REVISIOJrolS

I ZONE LTR OESCAIPTION \ OATE \ APPRoveD

NOTES,

I-~B~ --j6'1:L 1 156" 1--161- I 7L.f' 1-16[-[uu _ u -J ill 12" [ - - - - --

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ITEM 1 ITEM 2 ITEM 3 ITEM Lf 2 REOO 1 REDO 2 REDO 2. REQ'D

="lll BEND OOVJN 90° FOR LEFT SIDE BEND OO\JN 60°

~"II~ BEND UP 90" FOR RIGHT SIDE f- ~BEND DO\JN 30' -. ~tll -.l 1'1"[ ]]5 4- 7R~1~ ~-502"--l --1~!/~" f.- -66'- --1 --1r-'/~ o 0 0 0 L

2" +lIFT 3"T -0 --r 121- 0- T 1~.8" T I I I I ~i DRILL 'i 5{DIA HOLES 11;;

AF TER ASSE.MBLY TO 57"

-1 '"- i:lJl'+,J

'is'' r-18'+-36'--=J 12" L MATCH ITEM6

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...L -0-0 - 0-0- ITEM 8 ITEM 5 5,:::r 1 REO'Ol 2. REQ'O

DRILL 8 '7'~DIAHOLES ITEM 7

2. REQO-llEFT-l RIGHT ITEM 6

-Is' r--= -.11 ""rr 1 REdD ~2ULl ~ " t %:

BEND DO\JN 90· 2" b " -

Ill-57' ~nH

DRILL 2 %'DIA HOLES AFTER ASSEMBLY TO FIT 11'[11 9

11 -~- ITEM 10 # 0 0 ,J 1s'3 _0 03 ---L- 2 REQ'O

~~5' 10 2- 1.( ,, '-1',,'/ '1" ANGLE 5

DRILL Y '¥so DIA , HOLES 'j 1 '/'i' PLATE 62-8 2 ' / y" PLATE 8"1 CCNTR

7 2. ~/";' PL ATE 151 ORAWN

6 1 '14" PLATE 2'10 OESIGNER

ITEM 9 "- CHECK

5 2 '-l '~ y", ' /-i' ,I\NGLE 25 STRESS E'XTUIDrD BUMf-'lR G~::) IGN FOR f\

1 REO'D '1 2 Ei'xb 'x.'/~ '-lb KS I YIE.LO 1,9 '- ENG" WABc.D 178 TON TRUCK

3 2 18'><b\ ,/..;' Yb Ksi YIELD 1.67 P.".

RELEASE

2 1 lB"xb'x l /y' '16 K, 5i YIELD SlO SIZE ICOOE IOENT N0l ORA WING NO,

1 2 12'~ b"", l/ci % K,j YIELD 120 C l'ig-l0l

ITEM OTY DESCRIPTION \.iT SCALE SHEET ~ OF '3

FIGURE D"1"-Extended bumper design for WABCO 170·st-capaclty truck"

r NOTES, TOP V IEW

- - ----156"----------.1

-- - - -- -- ---- ----- ---- - ----- - --- -- -r-15"

------- + -------------I-r-~lf

ITEM2. r ~~,31.2'l ITEM 3 2. REQ'D 1-----7Y"~

ITEM 11 1 REo.'D

REVISIONS

DESCRIPTION

2. SIDE5~,-~ TOP VI Ew

r ITEM 2

U 2. SIDES

~ ITEM3

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CCNTR

DRAWN

DESIGNER

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ITEM1-: :

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HEM 12. - - --1 REOD

f="RONT ViE.W

+--IT[l13

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___ -- --.,--- ITEM 5 FLUSH 'WITH

ITEM 13 1 REQ'~

TOP AND FRONT

ITE.M 10 FLUSH WITH FRONT

f-:~=;~=C~:--+--+----4 EXTENDED BUMPER DE.SIGN FOR Po.

f:L::c.E::::NG~R+_+-_ _ _ -t WABlO 170 TON TRUCK P.A.

RELE ASE

DRAWING NO.

\HEET 2 OF 3

FIGURE D·1.-Extended bumper design for WABCO HO·st·capacity truck-Continued

c en Cl o ~ :D Z

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" :D

Z -l Z Cl

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NOTES,

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I

REY 1!tIOtH~

oeSCRIPTION OA T E "'PPRoveo

NOTES :

&. HEADLIGHTS TO BE MOUNTE.D BE.HIND FRONT PU\TE . LOCATION AND CUTOUT DETERMINED BY HARD'w'ARE AVAILABL E.

& SIDE MARKER LIGHT S TO BE MOUNTED ON SID[ PU\TE.S USING AVAILI>.BLE. HARD'w'ARE .

.&. PLATE TO BE WE.LDE.D USING 'N' FILLET.

& MAY INSTPILL AFTER ITEM 1 15 IN PLAC.E .

o ITEM NO.

BOTH SIDES

:EXTE.NDED BUMPER DESIGN FOR 1\ : WABC.O 170 TON iRUCK

DRAWING NO ,

lY'j-101

SHEET J OF 3

FIGURE O·1.-Extended bumper design for WABCO 170·st·capacity truck-Continued

N Co