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---==~ --Tr~opgrlaliow\ - llllO l"wbbo, Colocsdo 11001 Test

Cenrer

Mr. RobertS. Spratling Cont.ra.cting Officer

Federal Ra.1lroa.d Administration

1\ 55()( \ATIUN OF AJ,!EIUCAl'\

RAilROADS

Office of Acquisition s.nd Grants Services, RAD-30 400 Seventh street, S.W. Washington, DC 20590

Februa:ry 10, 1995 CON/ERW /95-()27

Tflc!u:(71Q) 58J-D672

Suqj: Dra.ft Fina.l Report - •weARS Modeling in SUpport of Freight ca.r Tolerance Side Bearing Clea.ra.nce Test •

Refr: Contract DTFR53-93-c-DOOO l, Task Order No. l 0 l, Modification No. 2

Dea.r Mr. Spratling:

Here. is the ~ect report for FRA review a.nd comment. It is AAR's intent to furnish the f'inaJ version within ten (10) da;ys from receipt of FRA's comments. Please fax

any ·changes to me on 719.584.0711 and we'll ma.ke a best efforts attempt to meet

our contractual obligation submission date of February 28, 1995 for the rmsJ version.

ERW;jp

oo: G. Deily, T~hultz,

y<!. Spons,

D. Cackovic P. Conlon

RDV-31 RDV-32(;L) RTC-Ql

K. Ha.wthorne C.Sha.nk

Sincerely,

ASSOCIATION OF AMERIC.A:ti R.AU..Jl.OADB

-;r~;Jt._· "7

Edward R. Walsh Contra.cts, Ma.n&ger

U.S. Department of Transportation

Federal Railroad Administration

Office of Research and Development Washington D.C. 20590

DOT/FRA/ORD-

NUCARS MODELING IN SUPPORT OF FREIGHT CAR TOLERANCE SIDE BEARING CLEARANCE TEST

Steven M. Belport

Association of American Railroads Transportation Technology Center Pueblo, Co 81001

February 1995 -DRAFT This document is available to the U.S. public through the National

Technical Information Service Springfield, Virginia 22161

DISCLAIMER

This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for the contents or use thereof. The United States Government does not endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to the object of this report.

j_!.: . H·l·,,.

METRIC CONVERSION FACTORS Approximate Conversions to Metric Measures Approximate Conversions from Metric Measures

9 - 23 Symbol When You Multiply by To Find Symbol - Symbol When You Multiply by To Find Symbol

Know ___ 22 Know

LENGTH - - 21 LENGTH 8 - -

in inches *2.50 centimeters em - :::::::_---20

mm millimeters 0.04 inches in ft feet 30.00 centimeters em - em centimeters 0.40 inches in yd yards 0.90 meters m --- - 19 m meters 3.30 feet ft mi miles 1.60 kilometers km -= _ m meters 1.10 yards yd

7 - 1 B km kilometers 0.60 miles mi

A.BI;.A - - 17

--:= _ AREA in2 square inches 6.50 square centimeters cm2 --= 16 ft2 square teet 0.09 square meters m2

6 - cm2 square centim. 0.16 square inches in2

yd2 square yards 0.80 square meters m2 - - 15 m2 square meters 1.20 square yards yd2

mi2 square miles 2.60 square kilometers km2 - km2 square kilom. 0.40 square miles mi2

acres 0.40 hectares ha : ::- 14 ha hectares 2.50 acres (10,000 m2

) - 13

MASS {weight) 5 -= MASS lweiaht\ - 12

oz ounces 28.00 grams g ----:= g grams 0.035 ounces oz lb pounds 0.45 kilograms kg - - 11 kg kilograms 2.2 pounds lb

short tons 0.90 tonnes t : t tonnes (1 000 kg) 1.1 short tons (2000 lb) 4 - 10

: VOLUME - - 9

VOLUME ....::. ml milliliters 0.03 fluid ounces fl oz = - 8 I liters 2.10 pints pt

tsp teaspoons 5.00 milliliters ml 3 - I liters 1.06 quarts qt Tbsp tablespoons 15.00 milliliters ml -= - 1 I liters 0.26 gallons gal fl oz fluid ounces 30.00 milliliters ml : m3 cubic meters 36.00 cubic feet ft3 c cups 0.24 liters I _ - 6 m3 cubic meters 1.30 cubic yards y& pt pints 0.47 liters I qt quarts 0.95 liters I 2 - - 5 gal gallons 3.80 liters 1 TEMPERATURE (exact) ft3 cubic feet 0.03 cubic meters m3

- - 4 y& cubic yards 0.76 cubic meters m3

- 'C Celsius' 9/5 (then Fahrenheit 'F -

3 temperature add 32 temperature

TEMEERAIUBE (exact) 1 = - 2

'F Fahrenheit 5/9 (after Celsius 'C --= - 1 oF 32 9 6 ;:2 temperature subtracting temperature : -40 o 140 so a~. 120 160 200 I

32) inches -= em 1 I I I I 1 I 1. I 1 I I I I _ I I I 1 I I I II I . - I I I I I I I I I I -40 -20 20 40 60 80 100 oc 0 37 oc

• 1 in. = 2.54 em (exactly)

Table of Contents

1.0 INTRODUCTION ..................................................................................................... 1

2.0 OBJECTIVE ................................................................................................................ 1

3.0 PROCEDURE ............................................................................................................ 1

3.1 NUCARS DESCRIPTION .................................................................................. 1

3.2 MODEL DEVELOPMENT ................................................................................ 2

3.2.1 System File .................................................................................................. 2

3.3 MODELING MATRIX ....................................................................................... 2

3.4 NUCARS INPUT FILE PARAMETERS ........................................................... 3

3.4.1 Input File ..................................................................................................... 3

3.4.2 Wheel/Rail Geometry File ....................................................................... 4

3.4.3 Data File ...................................................................................................... 5

4.0 RESULTS .................................................................................................................... 6

4.1 MODELING ANALYSIS ................................................................................... 8

4.1.1 D5 Configuration ....................................................................................... 8

4.1.2 D5 Configuration With Suspension Damping ..................................... 12

4.1.3 D7 Configuration (Long Travel Suspension) ......................................... 16

4.2 VARIATION IN COEFFICIENT OF FRICTION ............................................ 20

4.3 VARIATION OF TRACK GAGE ...................................................................... 22

4.4 COMPARISON TO CHAPTER XI LIMITS ..................................................... 23

5.0 CONCLUSIONS ....................................................................................................... 25

5.1 GENERAL OBSERVATIONS- CAR BODY ROLL ....................................... 25

5.2 GENERAL OBSERVATIONS-- WHEEL LOADS ......................................... 26

6.0 RECOMMENDATIONS .......................................................................................... 26

DRAFT REPORT

1.0 INTRODUCTION

The Federal Railroad RA) sponsered a research project with the Associ-ation of American Ra' (AAR~anaged Transportation Technology Center (TTC), Pueblo, Colorado, to investigate th~ effects of varia_tions in side bearing clearance on the vechicle dynamics of a loaded freight car with a relatively high center of gravity. AAR's computer program NUCARS was used to simulate the car's dynamic behavior.

This investigation was a continuation of another project (T0101,1993), which also tested a loaded freight car with a high center of gravity (e.g.), but on the Vibration Test Unit in TIC's Rail Dynamics Laboratory and on track.1 These early comparisons, between on-track tests and limited computer simulations, found in the analysis performed by Volpe National Transportation Systems Center (VNTSC) provided a basis for the studies included in this report.2

2.0 OBJECTIVE

The objective of this investigation was to support previous (1993) on-track testing and analytical modeling to further determine the effect of side bearing clearance in the presence of various secondary suspension configurations on high e.g. cars. Further parameters investigated were track gage, wheel/rail coefficient of friction, secondary spring stiffness, and the effect of hydraulic damping. All vehicle configurations were simulated using various track input amplitudes.

Prior to modeling, a preliminary review of all test data was conducted to obtain a better understanding of the overall test results and to help in the direction of the modeling effort.

3.0 PROCEDURE

The modeling effort involved various model configurations including side bearing clearance, wheel/ rail coefficients of friction, car suspension, track input amplitude and track gage. The configurations modeled were based on comments from FRA and discussions with VNTSC personnel.3 Review of the test plan resulted in modifications of the test matrix. These changes were made to better suit the overall objectives of the test program. All configurations were modeled on mathematically generated 39-foot staggered joints using standard wheel/rail profiles on a high e.g. covered hopper car.

3.1 NUCARS DESCRIPTION

NUCARS is a generalized vehicle dynamics program used to aid in vehicle design and testing. Vehicles are simulated in NUCARS as an assembly of body masses linked by connections representing actual suspension components. The flexible

DRAFT REPORT 1

7

structure of the model allows the user to simulate the response of any vehicle to any

track input. Simulation output includes predicted body and wheel set displacements, suspension forces and strokes, wheel/rail interaction forces, and wheel and rail wear indices.

The required input to accurately describe a specific vehicle includes masses

and dimensions of major body components, moments of inertia, and detailed information on all suspension locations, stiffness, damping characteristics and the e.g. height.

The model simulated the NUCARS mode of predicting forces and car body response resulting from the dynamics of the rolling wheel on rail.

3.2 MODEL DEVELOPMENT

Development of the initial NUCARS model for this application was performed by

personnel from VNTSC. This information was used as a baseline for the TTC model

ing effort to eliminate duplication of effort.

The following changes were made to the NUCARS system file provided by VNTSC for the D5 spring configuration._ All changes were agreed to by VNTSC per

sonnel and TTC engineers.

3.2.1 System File

- .003 inch was added to the desired side bearing clearance due to the center plate

spring stiffness (ie .. 250 to .253), which then allowed proper settling of the car

body center bowl.

- The side frame wedge angle on the Barber truck was changed from 37.5 degrees

to 35 degrees, appropriate for this truck design.

- The vertical spring rate for the bolster spring nest was changed to a standard

100-ton spring rate for the D-5 simulations.

3.3 MODELING MATRIX

Table 1 summarizes the test matrix configurations used for the NUCARS modeling.

DRAFT REPORT 2

Table 1. Modeling Configurations

I Parameter II Configuration I Classification Covered Hopper

Loaded Car Body Weight 266,000 lbs

C.G Height 93.0 inches

Side Bearings Roller 688B

Truck Type Barber, Variable Damped S-2-C

Truck Spacing 40.5'

Side Bearing Clearance 1/4" and 3/8"

Truck Suspension D5, D5 w /Hydraulic Damping, and D7

Speed 10 to 20 and 20 to 10 mph

10 to 30 and 30 to 10 mph

Track Gage 56; 56.5, and 57 inches

Wheel Profile Standard AAR-1B

Rail Profile AREA136

Input Amplitudes 0.75, 1.0 and 1.25 inches

Wheel/Rail Coefficient of 0.1, 0.3 and 0.5

Friction

The basis for this model is the AAR102 covered hopper car. This car has a history of testing dating back to when it was part of the Norfolk Southern Car Rocker Test Facility for testing trucks and snubbing devices. AAR102 is used by AAR/TTC for the conduct of specification testing. The car is currently loaded with packed cement powder.

3.4 NUCARS INPUT FILE PARAMETERS

3.4.1 Input File

Track inputs based on a rectified sine waveform, shown in Figure 1, were used during all of the modeling cases. Three input amplitudes (0.75, 1.0 and 1.25)

DRAFT REPORT 3

were selected based on the test data review and consultation with VNTSC per

sonnel. The length of the input was sufficient to clearly identify resonant speeds,

generally 1250 to 2500 feet. The distance-based rate of the input was set at 0.0085

mph/ foot of distance traveled. This is equivalent to a 10 mph change in velocity over 1170 feet.

PRE:VU PREVU Uersion Z.OO Association of Anerican Railroads

Copyright (c) 1992

0.0,_------------~.~--~.-~~~~~--~~--~.-~~--~~--

-o.z

-0.4

, ' ' ' ' '

l ---------------------~----- ------ - ------' ' ' ' ' ' ' ' ' : _____________________ i _____ _

' '

-0.6 ---------------------~------- ,------ ------- ----' ' ' ' ' '

i ! -0.8+---~~--~--;---~~--~--1---~~--~---r' --~--~~--~

50 100 150 PLOTTING LEFT VERT & RIGHT VERT uersus DISTAHCE

200 FEET

Chp XI Twist & Roll Input; 10 staggered low joints (3/4 in) on 39 ft rail

Figure 1. NUCARS Input File -- 3/4"

3.4.2 Wheel/Rail Geometry File

A description of the contact between the wheels and rails is required to run a

railroad track simulation using NUCARS. This is contained in the wheel/ rail geometry (WRG) file. The WRG file used for all modeling cases consisted of a standard AAR 1B wheel profile on an AREA 136-pound rail. Track gage variation in the WRG file included standard, narrow, and wide gage configurations.

Figure 2 shows a NUCARS plot of rolling radius change with wheel set lateral

position for this combination of wheel and rail at standard gage. The 1:20

tapered tread region is apparent during tread contact. The transition up the

flange is fairly continuous until two point contact occurs.

DRAFT REPORT 4

PRE:VU PREVU Version 2.00 Association of A~erican Railroads

Copyright (c) 1992

25.0,_---------,.---------~---------.---------.---------.~--------, ' ' ' ' '

ze.e __________ -L--------------~--------------~--------------~--------------~- -----------, ' ' ! : : : I I I I

: : : : 15.0 --------------~--- ---------~--------------~--------------~--------- ----~--------------1 I I I I

I I I I I I I I I I

:

1 I I I I

I : : : :

10.0 --------------:---- ---------:--------------:--------------:--------- ----:--------------1 I I I I I I I I I I I I I I I I I I I

s.e --------------L------- -----L--------------L--------------L---- --------L--------------l : i : i ' ' ' 0.0 ______________ : ---------~- ---- -- : --------------

' ' ' ' ' -5.0+-~~~~~~~~~~~~~~~r' ~~~~-+~~~~~r-~~~~ -15.0 -10.0 -5.a 0.0 5.0 10.0 15.0

PLOTTING Wheel Rolling Radius L uersus Lateral DisplaceMent

WHEELSET AAR1BWF MEASURED 06/08/93 ON RAILS AREA1364 MEASURED 06/29/91

Figure 2. Wheel Rolling Radius versus Lateral Displacement

3.4.3 Data File

Table 2lists the primary measurements which were evaluated using the

NUCARS model. Additional measurements were also collected for diagnostic

purposes during preliminary analysis. All data channels collected during simu

lations were high-pass filtered at 15 Hz.

DRAFT REPORT 5

Table 2. VTU Test Measurements Predicted by NUCARS

I Description II Location

Car Body Roll Rotation Center

Vehicle Velocity n/a

Vertical Wheel Force Axle 1,2,3 & 4

Axle Roll Rotation Axle 1,2,3 & 4

Bolster Roll Rotation A &BEnd

4.0 RESULTS

Simulations were performed based upon the model and input criteria described in Section 3.0 of this report. The primary mode of data reduction was conducted by combining the peak-to-peak roll angles with speed for each major run configuration.

I

Figures 3 and 4 show typical NUCARS plots of car body roll; the peak-to-peak roll angle of 5.5 degrees occurred at 12 mph. Figure 5 shows a typical history plot of speed versus distance during a downward sweep from 20 to 10 mph.

DRAFT REPORT 6

PLOTVU X17.0UT NUCARS Version 2.055 27-Dec-94 Transportation Test Center, Pueblo, Colorado

degrees 3.0,_-----------.-----------.------------.-----------.-----------,

I I

' ' ' ' ' ' ' ' ' ' 2. 0 ----------- -- ~-----------------~------------------~-----------------

1.0

···wJ --------

-1.0 --------- - - -

1 • I I

' ' ' ' ' ' ' ' ' ' ' ' ~ ' ' ' ' ' ' '

' ' ' ' ' '

r-- --r ------ r

' ' ' ' - - - -- - ' -~-- --

' ' ' ' -2.0 ------------ - - ----------------~------------------~-----------------' ' ' ' ' ' ' ' ' ' ' ' ' '

-3.0+-----~------+-----~------~----~----~:,_----~-----+:------~----~ 10.0 12.€1 14.€1 16.€1 18.€1

Car Body Roll Gyro uersus Forward Velocity 3/8" sbc, 3/4" input amplitude (RECTIFIED sine), 2e TO 1e mph, mu =.5

Figure 3. Time History-- Car Body Roll Versus Speed

2e.e mph

PLOTVU X17.0UT NUCARS Version 2.055 27-Dec-94 Transportation Test Center, Pueblo, Colorado

degrees 3.0,_-----------.-----------.------------.-----------.-----------~

' ' ' ' ' ' ' ' ' ' 2.0 ------------------~-----------------~-----------------~- -

1.0

··~ -1.0 ----------- -

' ' ' ' ' ' ' ' ' ' ' ' '

- - - - -

' ' ' ' ' '

H· - - -

' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' -2.0 ------------------!-----------------:----------------- - -- - - - - -! - -------------' ' ' '

-3.a+-~--~-.-,--+:--~-.-,--~-+:--,-~~--~~-,--~-r~,-4·--~-r--~~~ 25€1 see 75e 100€1

Car Body Roll Gyro uersus Distance along the Track 3/8" sbc, 3/4" input amplitude (RECTIFIED sine), 20 TO 1e mph, mu =.5

Figure 4. Time History -- Car Body Roll Versus Distance

DRAFT REPORT 7

1250 feet

X17.0UT NUCARS Version 2.055 27-Dec-94 PLOTVU Transportation Test Center, Pueblo. Colorado

20.0 lllph ~~~------:------------:1 -----------,-----------------------,

I I I I I I I I I I I 18.3 ------------------L- --------------~-----------------~------------------L-----------------1

I I I I I I I I I

: : : I I I I I I I I I I I I I I I I I I I I I

I I

---------------~------------------r-----------------------------------~-----------------i I I

16.0 I I I I I I I I I I I I I I I I

: I I I I I I I 14.0 ------------------~-----------------~----------------- -----------------~-----------------1 I

I I I I I I I I I I

: : I I I I

------------------L-----------------~-----------------~----------------12.0

1 I I I I I I I I I I I I I I I I I I I I I I I I I I

10.0+-~~~--~~:--~~~~--r: ~~~~~-+:~--~~~-+~--~~~~ o 250 500 750

Forward Velocity uersus Distance along the Track

3_...;8" she, 3/4" input a111plitude (RECTIFIED sine), 20 TO 10 111ph. 111u =.5

Figure 5. Time History-- Speed Sweep Versus Distance

4.1 MODELING ANALYSIS

1250 feet

Two performance measures were selected to analyze roll response from this modeling effort. The first is the maximum peak-to-peak roll angle. AAR freight certifica

tion standards place a limit of 6 degrees on this value. The second criterion is the

minimum vertical wheel load expressed as a percentage of the static wheel load.

AAR standards state that this value should not fall below 10 percent at any speed up

to the maximum operating speed.4 Values below this threshold identify potential

loss of wheel/rail contact and guidance. The following sections contain summary

plots from reduced data showing peak-to-peak car body roll versus speed of each

model configuration.

4.1.1 05 Configuration

Figures 6 through 8 show plots from the D5 truck spring configuration. Each

figure includes side bearing clearances of 1/4- and 3/8-inch side bearing

clearance. The figures are presented in order from 0.75, 1.00 and 1.25 track input

amplitudes respectively.

DRAFT REPORT 8

DRAFT REPORT

12

1/4' S.B. CLEARANCE X5.Xl4

14 16

SPEED(MPH)

--UPWARD SWEEP --e- DOWNWARD SWEEP

12

3/8" S.B. CLEARANCE X8,X17

14 16

SPEED(MPH)

--UPWARD SWEEP --e- DOWNWARD SWEEP

18

18

Figure 6. Car Body Roll Versus Speed 3/4" Input

9

20

20

14

8 12 ~

e. ~ 10 -l 0 z < -l -l 0 0:: ~ < ~ Q.,

0 f-~ < ~ Q.,

0

DRAFT REPORT

10 12

1/4' S.B. CLEARANCE X89,X90

14 16

SPEED (MPH)

--UPWARD SWEEP --DOWNWARD SWEEP

12

3/8" S.B. CLEARANCE X9l,X92

14 16

SPEED(MPH)

-- UPWARD SWEEP -- DOWNWARD SWEEP

18

18

Figure 7. Car Body Roll Versus Speed 1.0" Input

10

20

20

14

G' 12 r.LI 8 r.LI 10 -l 0 z < -l -l 0 ~

:.:: < r.LI ~

6 r-~ < r.LI ~

0

14

G' 12 r.LI 8 r.LI 10 -l 0 z < -l -l 0 ~

:.:: < r.LI ~

6 r-~ < r.LI ~

0

DRAFT REPORT

10

10

12

1/4' S.B. CLEARANCE X93,X94

14 16

SPEED (MPH)

--- UPWARD SWEEP --- DOWNWARD SWEEP

12


14 16

SPEED (MPH)


IS

18


11

20

20

4.1.2 05 Configuration With Suspension Damping

Figures 9 through 11 contain plots from the D5 with hydraulic damping truck spring configuration. Each figure includes side bearing clearances of 1 I 4- and 3/8-inch side bearing clearance. The figures are presented in order from 0.75, 1.00 and 1.25 track input amplitudes respectively.

DRAFT REPORT 12

DRAFT REPORT

IS


20

SPEED (MPH) 25



30

0 L_ ____________ L_ ____________ L_ ____________ L_ __________ ~

10 IS 20

SPEED (MPH) 2S



13

]0

DRAFT REPORT


0 L_----------~-------------L------------~----------~ 10 15 20

SPEED(MPH) 25

-- UPWARD SWEEP --DOWNWARD SWEEP


30

0 L_----------~-------------L------------~------------10 15 20 25 30

SPEED(MPH)

-- UPWARD SWEEP --DOWNWARD SWEEP


14

DRAFT REPORT

15


20

SPEED (MPH) 25


15


20

SPEED (MPH) 25



15

30

30

4.1.3 07 Configuration (Long Travel Suspension)

Figures 12 through 14 contain plots from the D7 truck spring configuration. Each figure includes side bearing clearances of 1 I 4- and 3 I 8-inch side bearing clearance. The figures are presented in order from 0.75, 1.00 and 1.25 track input amplitudes respectively.

DRAFT REPORT 16

1/4" 8.8. CLEARANCE X83,X71

14

6 12 ~ e ~ 10 ..J 0 z ..: ..J ..J 0 ~

::.:: ..: ~ ~

$ 4

::.:: ..: ~ ~

0 10 15 20 25 30

SPEED(MPH)

...._ UPWARD SWEEP -e- DOWNWARD SWEEP

3/8" 8.8. CLEARANCE X84,X72

14

6 12 ~

e ~ 10 ..J 0 z ..: ..J ..J 0 ~

::.:: ..: ~ ~

6 4 E-~ < ~

: t ~

• • 10 15 20 25 30

SPEED(MPH)

...._ UPWARD SWEEP -e- DOWNWARD SWEEP


DRAFT REPORT 17

14

0 12

~

8 ~

10 ...J 0 z <: ...J ...J 0 0:: ::..: <: ~ Q.,

6 E-;' ::..: <: ~ Q.,

0

14

0 12

~

8 ~

10 ...J 0 z <: ...J ...J 0 0:: ::..: <: ~ Q.,

6 f-. ~ <: ~ Q.,

DRAFT REPORT

10


15 20 25

SPEED(MPH)

--UPWARD SWEEP -- DOWNWARD SWEEP

15


20

SPEED (MPH) 25



18

30

30


I~ '

G " f [J..l Q

[J..l I ..J 10

0 z -< ..J ..J 0 0::: ::.:: -< [J..l r:>...

6 f-~ -< [J..l r:>...

0 10 15 20 25 30

SPEED (MPH)

--UPWARD SWEEP -- DOWNWARD SWEEP


14

G 12 [J..l

B -~ 10

0 z -< ..J ..J 0 0::: ::.:: -< [J..l r:>...

6 4 !-;' ::.:: -< [J..l r:>...

0 10 15 20 25 30

SPEED (MPH)



DRAFT REPORT 19

4.2 VARIATION IN COEFFICIENT OF FRICTION

Figures 15 through 17 show history plots of car body roll versus speed for each variation of the wheel/rail coefficient of friction (0.1, 0.3, and 0.5.). Results from these plots show that no significant differences in car body roll were detected when the wheel/rail coefficient of friction was changed. This analysis, conducted at the beginning of the modeling runs, concluded.that a wheel/rail coefficient of friction of 0.5 would be used for the remainder of the modeling runs.

DRAFT REPORT 20

PLOTVU I X16.0UT liUCARS Version 2.055 27-Dec-9"1 Tr~tnsportat. ton Test Center~ Pueblo~ Co lorado

3.0 degrees

2.0

~iii"~M~~MM~r:-~it[~:~~:~ 1.0

0.0

-1.0

-2.0

: : : : -3.0 ! : i

Hl.O 12.0 11.0 16.0 16.0 20.0

l!i.mii~DJmDI.~II;a•'l~i11~JU:I; 1 SiiZ:.!mm::IU!I nph

1/-t" sbc, 3/"''" input. anplit.ude <RECTIFIED sine), 20 TO 10 r.ph. nu ::;:;.1

Figure 15. Time History -- Car Body Roll Versus Distance COF = .1

PLOTVU X15.0UT liUCARS Version 2.055 26-Dec-9"1 Transportation Test Center~ Pueblo, Colortt.do

degrees 3.0,_--------~--------~------~--------~---------,

2. 0 ------------------t·------ - - -r-----------------:-----------------1. e __________________ L:, ____ • •

!" -

-1.0 ----------------·-t··- -

~:::+-------------~-------------~~-----------~-----~----~-----~r_-_--_--_--~--------------+r------------~----------~--10.0 12.0 11.0 16.0 16.0 20.0

l!ttr!MitijfTWIGJIMhiiQ•Mii3f11f¥§•iQ161J,Wif9ti!S!I0 nph 1/4" sbc, 3/4." input anplitude (RECTIFIED sine), 29 TO 10 r.ph. n~u =.3

Figure 16. Time History -- Car Body Roll Versus Distance COF = .3

PLOTVU XH.OUT liUCARS Version 2.055 26-Dec-9"1 Transport.at fen Test Center, Pueblo, Co lorado

Figure 17.

DRAFT REPORT

degrees 3.0,_--------,---------~------~--------~---------,

2. 0 ------------------t··----- - - -:------------------:-----------------1.0 -----------------+---- ' - - - - - '

o.o

10.0 12.0 H.O 16.0 16.0

•ftt!W:nr;rrw:m••n••A·*'I4f1'f'-Mi"'4'6'J·••mmaum "Ph 1/"'1" sbc, 3/4" inJIUt anaplit.ude <RECTIFIED sine), 20 TO 10 RJlh, nu "'.5

Time History -- Car Body Roll Versus Distance COF = .5

21

4.3 VARIATION OF TRACK GAGE

Figures 18 and 19 show x-y plots of peak-to-peak car body roll versus speed during the two test modes (sweep-up and sweep-down). Configurations of narrow (56 inch), standard (56.5 inch), and wide (57 inch) track gage are included in each plot. Both test modes consistently defined that the greatest peak-to-peak car body roll occurred when a narrow track gage of 56-inches was used. Since the change in the peak-to-peak roll angle was typically less than 1 degree, the remainder of the modeling runs were conducted using an standard track gage (56.5 inches).

CARBODY ROLL ANGLE X5,X25,X5W (SWEEP UP)

IL-------~------~--------~------~------~ 10 12 14 16 18 20

SPEED(MPH)

-- 56.5 GA -+- 56 GA ......- 57

Figure 18. Variation of Track Gage-- Sweep Up

DRAFT REPORT 22

CARBODY ROLL ANGLE Xl4,X34,X44 (SWEEP DOWN)

I L--------L--------~------~--------~------~ 10 12 14 16 18 20

SPEED (MPH)

--- 56,5 GA --+- 56 GA -r- 57

Figure 19. Variation of Track Gage -- Sweep Down

4.4 COMPARISON TO CHAPTER XI LIMITS

Figures 20 through 22 show plots of compiled wheel loads and peak-to-peak car

body roll angles for each of the three input amplitudes, 0.75 inch, 1.0 inch and 1.25

inch. Each plot shows a comparison between the values obtained from selected sim

ulations and the allowable AAR specification limits for car body roll and minimum

vertical wheel load.

DRAFT REPORT 23

DRAFT REPORT

15

;;;-U.l U.l 0:: CJ U.l e 10

...l

...l 0 0:: ~ < U.l c.. 6 f-~ < U.l c..

DS SPRINGS

b.

b.

b.

--- -

l/4UP 3/l! UP l/4DN 3/RDN

• PEAK-TO-PEAK ROLL

_CHI! LIMIT

0.751NPUT DS W/DAMPING

b. b. b. b.

- - - -I/4DN 3/RDN

1/4 UP 3/l! UP

CONFIGURATION

D7 SPRINGS

b.

b.

b.

-- -

I/4UP 3/8 UP 1/-lDN

6 MIN. VERT. WHEEL LOAD

25

;;;-c..

20 :;;: U.l u

b. 0::

15 0 "-...l U.l

= 10 §: - ...l

< u 1= 0:: U.l >

3/8DN

Figure 20. Wheel Loads and Car Body Roll Plot-- 3/4" Input

DS SPRINGS 1.00 INPUT

DS W/DAMPING D7 SPRINGS 15 r--------------,-----------------,--------------0

I/4UP 3/8 UP l/4DN 3/8DN

• PEAK-TO-PEAK ROLL

_CHI! LIMIT

b.

b.

b. b.

b.

l/4DN 3/8DN 1/4 UP 3/8 UP 114 UP 3/8 UP l/4DN 3/SDN

CONFIGURATION

6 MIN. VERT. WHEEL LOAD

25

;;;-c..

20 :;;: U.l u 5

15 L.:..

~ :iS :c

10 :::: ...l < u 1= 0:: U.l >

Figure 21. Wheel Loads and Car Body Roll Plot --1.00" Input

24

1.25 INPUT 05 SPRINGS 05 W/DAMPING 07 SPRINGS

15 25

"' ~ (J..l (J..l - 20 ~ c:::: 0 :..t..l (J..l - u e 10 c::::

0 ...l 15 ~ ...l

"' ...l 0 WJ c:::: "' w..::

)<! :t -< 10 ~ (J..l Q.. ...l 6 "' -< u c- ;:: 1= ~ c:::: -< (J..l (J..l > Q..

I/4UP 3/8UP I/4DN 3/8DN I/4UP 318UP I/4DN 3/SDN 1/4UP 318UP l/4DN 3/SDN

CONFIGURATION

- PEAK-TO-PEAK ROLL "'

MIN. VERT. WHEEL LOAD

_CHI! LIMIT

Figure 22. Wheel Loads and Car Body Roll Plot -- 1.25" Input

5.0 CONCLUSIONS

The following observations are based on the modeling configurations included only in this report. These observations may not, in some cases, directly apply to the previous test data where a much wider spectrum of testing was analyzed. Typical examples include prior test data from configurations of 1/8 inch, 1/2 inch and 3/4 inch side bearing clearance, compared to observations of 1/4 inch and 3/8 inch included in this report.

5.1 GENERAL OBSERVATIONS- CAR BODY ROLL

Downward sweep runs always produce a lower frequency peak roll angle when compared to the upward sweep. Typically, it is of greater amplitude than the upward sweep.

Vehicle roll angle increases with input amplitude; the largest, increased between 0.75- and 1.0-inch input amplitude.

The variation of side bearing clearance modeled, 1/4 inch and 3/8 inch, had little influence on roll angle. Previous test results showed that larger side bearing clearance gap changes did affect car body roll angles.1

Spring type (D5 vs D7) has a very small effect on peak-to-peak roll angle.

DRAFT REPORT 25

Hydraulic damping significantly reduces the peak-to-peak roll angle. Wheel/ rail coefficient of friction and track gage have a negligible impact on roll angle.

0.75-inch input produced no roll angle in excess of the AAR 6-degree limit. For the 1.00-inch input amplitude, D5 and D7 undamped configurations, 6 of 8 simulations produced peak-to-peak roll angles above the 6-degree specification limit.

At 1.25-inch input amplitude, all configurations without additional damping exceeded the 6-degree limit. All cases produced peak-to-peak roll angles between 10 and 12 degrees.

5.2 GENERAL OBSERVATIONS-- WHEEL LOADS

For 0.75-inch input amplitude, the minimum wheel load is never less than 30 percent of static wheel load regardless of spring/ damper arrangement. For the D5 damped arrangement it is never less than 60 percent of the static load. It is anticipated that very worn trucks with lower damping capability as tested previously, could have produced wheel unloading of greater significance if modeled.

With 1.0-inch input amplitude, half of the cases produced wheel lift although none of these were with hydraulic damping. At 1.25-inch input amplitude, all D5 and D7 configurations without hydraulic damping generated wheel lift.

With 1.25-inch input amplitude, D5 configuration with hydraulic damping maintained at a minimum of 18 percent of static wheel load.

6.0 RECOMMENDATIONS

This study covered only a small range of possibilities in terms of harmonic roll response for high e.g. vehicles. The repeated jump response detected with the upward and downward sweeps illustrate the difficulty in identifying a safe, low operating speed.

The different side bearing clearances modeled, 1/4 inch and 3/8 inch, provide little or no additional margin of safety. Hydraulic damping at its optimal level can greatly reduce the risk of wheel lift and therefore derailments. The durability of hydraulic dampers may still be questionable in addition to these benefits given purchase, installation, and maintenance expense.

If the roll performance is a proven safety concern, then additional investigation of roll moderation techniques should be performed. This should also include a survey of the track geometry for amplitude, wavelength, and repeat distance.

DRAFT REPORT 26

A vehicle survey with regard to the population of vehicles equipped with vertical damping would also be of value. An estimate of high e.g. limits typically produced should be tabulated. Upon completion, a program consisting of testing and computer modeling should be developed to verify new railcar designs and track safety standards.

DRAFT REPORT 27

References 1. Cackovic, Dave L., Kerry Hopkins, David Tyrell. "Side Bearing Clearance Testing

Research." Federal Railroad Administration, FRA/ORD/94-11, May 1994. 2. Dorsey, C., David Tyrell, Herb Weinstock, R. Greif. "Analysis of Tests Conducted to

Determine the Influence of Side Bearing Clearance of Freight Car Harmonic Roll Behavior." U.S. Department of Transportation Volpe National Transportation Systems Center, Cambridge, MA, 1994 ASMEPaper.

3. Weinstock, Herbert, E-Mail Message to Tom Schultz (FRA)--AAR-Modification to T0101. U.S. Department of Transportation Volpe National Transportation Systems Center, Cambridge, MA, October 13, 1994.

4. Association of American Railroads, Manual of Standards and Recommended Practices. "Chapter XI Service-Worthiness Tests and Analysis for New Freight Cars." Washington, DC., 1991.

DRAFT REPORT 28

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