measurement and analysis of us truck vibration for leaf spring and air ride suspensions, and...

PACKAGING TECHNOLOGY AND SCIENCEPackag. Technol. Sci. 2006; 19: 309–323Published online 19 April 2006 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/pts.732

Measurement and Analysis of US TruckVibration for Leaf Spring and Air RideSuspensions, and Development of Tests toSimulate these Conditions

By Jagjit Singh,1 S. Paul Singh2* and Eric Joneson3

1 Orfalea School of Business, California Polytechnic State University, San Luis Obispo, CA, USA2 School of Packaging, Michigan State University, East Lansing, MI, USA3 Lansmont Corporation, Lansing, MI, USA

There is a significant amount of goods that are transported using tractor trailers.Most high-value products, such as electronics, highly perishable goods like fruitsand vegetables and most retail consumer products, are shipped using trucks inNorth America. It is therefore important to measure and quantify the levels ofvibration that occur inside this mode of transport as it pertains to damage.Vibration levels inside a tractor-trailer are a function of the road surface, the speedof the vehicle, the type of suspension and the structure of the trailer. The purpose ofthis study was to determine the levels of vibration as a function of trailersuspension at normal operating speeds in commercially used truck equipment, over16000km of road surfaces in North America. Copyright © 2006 John Wiley & Sons,Ltd.Received 27 September 2005; Revised 7 December 2005; Accepted 27 January 2006

KEY WORDS: vibration; truck; suspension

* Correspondence to: S. P. Singh, School of Packaging, Michigan State University, East Lansing, MI, USA.E-mail: [email protected]

Copyright © 2006 John Wiley & Sons, Ltd.

INTRODUCTION

Truck transport is the most common way used todistribute retail and consumer goods products inthe USA. In most cases, damage to products andpackages can be attributed to the various vibrationforces that occur during distribution. Previousstudies have been done1,2 to measure and quantifythese levels so that engineers can design productsand packages to withstand these levels. The previ-ous data investigated consisted of small section ofroad trips (<150km) that were analysed and com-pared, and were limited to one or two tractor trail-ers. The current study is aimed at gathering dataover a large section of the North American

highway network, using more than 10 commer-cially available tractor-trailers. The focus of thisstudy was to compare the difference in vibrationlevels between leaf spring and air-ride tractor-trailer suspensions and develop methods to simu-late these conditions in a laboratory environment,using tests methods such as American Society ofTesting and Materials (ASTM) D4728.

A typical power spectral density (PSD) functionshows the strength of the vibrations (energy) as afunction of frequency.3 In other words, it shows atwhich frequencies vibrations are strong and atwhich frequencies vibrations are weak. The unit ofPSD is energy (power density in G2/Hz) per fre-quency (Hz): energy within a specific frequency

range can be obtained by integrating PSD withinthat frequency range. Computation of PSD is donedirectly by the method called Fourier transforma-tion, or computing autocorrelation function andthen transforming it.

A PSD plot is an important tool in simulatingreal-life transportation conditions on vibrationequipment in a laboratory. Figure 1 shows anexample of an actual PSD plot for a loaded trailerwith leaf spring suspension going over an inter-state expressway, used to simulate a truck ride ona vibration table. Some of the typical sources ofvibration are also defined.

The purpose of this study was to investigate thevibration forces that occur during truck transportof glass racks and glass packaging for a sheet glass manufacturer. Shipments from three differentplants were instrumented with Lansmont SAVER(Model Number: SV-1) acceleration recorders tomeasure the vibration levels. The recorders were

mounted at the rear location of the trailer (Figure2). Previous studies conducted by Michigan StateUniversity have found that the rear floor locationgenerates the highest vibration levels during ship-ment. The shipments were monitored from the fol-lowing three glass manufacturing plants: Carlisle,PA; Mt. Zion, IL; and Wichita Falls, TX.

The shipments were made to customers that currently receive product from the glass manufac-turer. A combination of air-ride and leaf spring sus-pensions were studied (Figure 3). All trailers usedin this study were fully loaded with glass product(approximate weight, 46000 lb or 20900kg).

The origin and destination cities, approximatedistance monitored and type of trailer suspensionused are listed in Table 1 and illustrated in Figure4.

This paper provides the results of vibration mea-surement and analysis conducted on behalf of theglass manufacturer. The data was collected andanalysed to develop PDS for the various routes. Inaddition composite PDS were developed to simu-late test racks for the glass manufacturer. Thisstudy also measured the temperature and humid-ity measured in these shipments. The study wasconducted in 2001–2002.

J. SINGH ET AL.Packaging Technologyand Science

Copyright © 2006 John Wiley & Sons, Ltd. 310 Packag. Technol. Sci. 2006; 19: 309–323DOI: 10.1002/pts

1 2 3 10 30 100 20

0.00000

0.01

0.0001

1

Power Density (G2/Hz)

Frequency (Hz)

Suspension 3-4 Hz

Tires 15-20 Hz

Structure (floor)40-55 Hz

Figure 1. A typical PSD plot for truck transportation.

DataRecorder

LEAF SPRING SUSPENSION AIR RIDE SUSPENSION

Figure 2. Recorder location on trucks.

Figure 3.Types of trailer suspensions.

OBJECTIVES

The study had the following objectives:

1. To measure vibration levels in truck shipmentsof glass product and packaging to various cus-tomers from three manufacturing plants.

2. To compare the vibration levels in air ride vs.leaf spring suspension trailers.

3. To develop laboratory simulated vibration testmethods to simulate truck shipments.

4. To measure temperature and humidity in truckshipments.

DATA MEASUREMENTPARAMETERS

Two data recorders (Figure 5) were used for theduration of the study to be used to measure thevibration levels. The following settings were used:

• Minimum time triggered sampling: 10min.• Trigger threshold level: 2.4G.• Minimum sampling rate: 651 samples/s.• Minimum recording window: 1.57s.• Sample size: 1024.• Temperature/humidity intervals: same as

vibration sampling.


VIBRATION LEVELS IN US TRUCK SHIPMENTS Packaging Technologyand Science

Table 1.The origin and destination cities, approximate distance monitored, and type of trailersuspension used

TRIP 1: Manufacturer at Carlisle, PA, to Ellison Windows and Doors,Welcome, NC430 miles; leaf springTRIP 2: Manufacturer at Carlisle, PA, to manufacturer at Works 28, Evansville, IN680 miles; leaf springTRIP 3: Manufacturer at Carlisle, PA, to Harvey Industries, Manchester,NH 445 miles; air rideTRIP 4: Manufacturer at Carlisle, PA, to Survivor Technologies, South Hills, NJ200 miles; air rideTRIP 5: Manufacturer at Carlisle, PA, to Gardner Mirror Products, North Wilkesboro, NC400 miles; air rideTRIP 6: Manufacturer at Carlisle, PA, to manufacturer at Works 80, Hawkesbury, ON, Canada490 miles; air rideTRIP 7: Manufacturer at Carlisle, PA, to Arch Mirror South, Ft. Pierce, FL1050 miles; air ride flat bedTRIP 8: Manufacturer at Carlisle, PA, to Binswanger Mirror, Grenada, MS1135 miles; air rideTRIP 9: Manufacturer at Wichita Falls,TX, to Nokomis, Florida, Route 11245 miles; leaf springTRIP 10: Manufacturer at Wichita Falls,TX, to Salt Lake City, UT1332 miles; air rideTRIP 11: Manufacturer at Mt. Zion, IL, to manufacturer at Works 27,Tipton PA625 miles to Leaf SpringTRIP 12: Manufacturer at Mt. Zion, IL, to manufacturer at Works 81, Oshawa, ON, Canada680 miles; air rideTRIP 13: Manufacturer at Mt. Zion, IL, to Carlex,Vonore,TN625 miles; air rideTRIP 14: Manufacturer at Mt. Zion, IL, to Chrysler, Detroit, MI425 miles; leaf spring

RESULTS

The data and results of the study are provided inthe various PDS and are listed in the followingorder.

Table 1 lists the various trips, routes, distancestravelled and truck types studied. Table 2 com-pares the summarized overall data for Trips 1–14.The PDS are a plot of the frequency (in Hz) dis-played on the x axis and the corresponding intensity of vibration (power density, in G2/Hz)displayed on the y axis. Figures 6–18 describe theindividual PDS for the trips measured at the rearlocation of the trailer in the vertical mode.

Figures 19 and 20 show the composite testspectra that were developed from the above data.These represent the first composite spectrum(Figure 19) for all the leaf spring shipments for theCarlisle and Wichita Falls plants and the secondcomposite spectrum for all the leaf spring ship-ments from the Mt. Zion plant (Figure 20). Thesetwo spectra were also used to validate testing ofvarious forms of glass packaging and rack. Thespectra show the higher level PDS representing thetop 30% of data recorded and the lower PDS rep-resenting the lower 70% of the data recorded.There is not a significant difference in vibrationlevels for shipments from Carlisle/Wichita Fallswhen compared to Mt. Zion originating plants.

Figure 21 and 22 show the two compositespectra prepared for all leaf spring shipments andall air ride shipments from all three plants.

CONCLUSIONS

Air ride vs. leaf spring

Table 1 summarizes the data collected in these 14shipments. The data is presented in Grms levels for



CARLISLE, PAMT. ZION, IL

WICHITA FALLS, TX

Evansville, IN

Manchester, NH

South Hills, NJ

N. Wilksboro, NC

Hawkesbury, ON, Canada

Ft. Pierce, FL

Grenada, MS

Nokomis, FL

Salt Lake City, UTTipton, PA

Oshawa, ON, Canada

Vonore, TNWelcome, NC

Detroit, MI

LEAF SPRING

AIR RIDE

SHIPMENT ORIGIN

SHIPMENT DESTINATION

Figure 4.The origin and destination cities and type of trailer suspension.

Figure 5. Lansmont SAVER model SV-1.



Table 2.Vibration data for trips 1–14

Spectrum power Temperature Relative

Distancedensity (Grms) (°F) humidity (%)

Trip Suspension (miles) 30% High 70% Low Min Max Min Max

1 Leaf spring 430 0.32 0.20 53.8 72.4 33.7 57.32 Leaf spring 680 0.55 0.37 46.8 64.1 33.5 70.23 Air ride 445 0.20 0.10 41.3 63.4 26.1 53.84 Air ride 200 0.37 0.17 37.8 57.9 48.2 65.35 Air ride 400 0.28 0.13 55.2 72.9 48.3 54.66 Air ride 490 0.13 0.07 66.5 69.0 30.5 40.07 Air ride 1050 0.11 0.06 39.0 69.9 30.6 72.88 Air ride 1135 0.10 0.10 59.0 70.0 30.5 52.99 Leaf spring 1245 0.89 0.60 66.8 84.2 45.2 64.4

10 Air ride 1332 0.36 0.23 44.3 66.8 61.1 71.211 Leaf spring 625 0.45 0.24 51.1 70.1 60.0 70.012 Air ride 680 0.50 0.25 45.6 67.1 43.9 71.613 Air ride 625 Bad data Bad data 35.0 67.1 21.5 41.514 Leaf spring 425 0.37 0.21 34.6 67.5 31.6 55.1

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 1000100

Frequency (Hz)

PS

D (

G2 /

Hz)

30% High - 0.32 Grms

70% Low - 0.20 Grms

Figure 6.Trip 1: manufacturer at Carlisle to Ellison Windows & Doors,Welcome, NC; leaf spring.



1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10010 1000

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.37 Grms

Figure 7.Trip 2: manufacturer at Carlisle to manufacturer at Evansville,IN; leaf spring.

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 1000100

Frequency (Hz)

PS

D (

G2/H

z)


70% Low - 0.10 Grms

Figure 8.Trip 3: manufacturer at Carlisle to Harvey Industries,Manchester, NH; air ride.



1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 1000100

Frequency (Hz)

PS

D (

G2/H

z)


70% Low - 0.17 Grms

Figure 9.Trip 4: manufacturer at Carlisle to Survivor Technologies, SouthHills, NJ; air ride.

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10001 1000

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.13 Grms

Figure 10.Trip 5: manufacturer at Carlisle to Gardner Mirror Products,N.Wilksboro, NC; air ride.



1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 1000100

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.07 Grms

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 100 1000

Frequency (Hz)

PS

D (

G2/H

z)


70% Low - 0.06 Grms

Figure 11.Trip 6: manufacturer at Carlisle to manufacturer atHawkesbury, ON, Canada; air ride.

Figure 12.Trip 7: manufacturer at Carlisle to Arch Mirror South, Ft.Pierce, FL; air ride.



1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 100 1000

Frequency (Hz)

PS

D (

G2/H

z)


70% Low - 0.10 Grms

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 1000100

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.60 Grms

Figure 13.Trip 8: manufacturer at Carlisle to Binswanger Mirror,Grenada, MS; air ride.

Figure 14.Trip 9: manufacturer at Wichita Falls to Nokomis, FL, Route 1;leaf spring.



1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 100 1000

Frequency (Hz)

PS

D (

G2 /

Hz)

70% Low - 0.23 Grms


1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 100 1000

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.24 Grms

Figure 15.Trip 10: manufacturer at Wichita Falls to Salt Lake City, UT;air ride.

Figure 16.Trip 11: manufacturer at Mt. Zion to manufacturer at TiptonPA; leaf spring.



1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 10 1000100

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.25 Grms

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

10 100010010

Frequency (Hz)

PS

D (

G2 /

Hz)


70% Low - 0.21 Grms

Figure 17.Trip 12: manufacturer at Mt. Zion to manufacturer atOshawa, ON, Canada; air ride.

Figure 18.Trip 14: manufacturer at Mt. Zion to Chrysler, Detroit, MI;leaf spring.



1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

10 100010010Frequency (Hz)

30% High - Averaged -0.727 Grms

70% Low - Averaged - 0.430 Grms

PS

D (

G2 /

Hz)

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

10001001010

Frequency (Hz)

PS

D (

G2 /

Hz)

30% High - 0.714 Grms

70% Low - 0.231 Grms

Figure 19. Composite test spectrum 1: manufacturer at leaf springtruck shipments, Origin, Carlisle, PA and Wichita Falls,TX.

Figure 20. Composite test spectrum 2: Mt. Zion leaf spring averagePSD.



1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

10 10 100 1000

Frequency (Hz)

PS

D (

G2 /

Hz)

30% High Average - 0.283 Grms

70% Low Average - 0.146 Grms

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

10 100010010

Frequency (Hz)

PS

D (

G2 /

Hz)

30% High Average - 0.659 Grms

70% Low Average - 0.354 Grms

Figure 21: Air ride composite PSD plot.

Figure 22: Leaf spring composite PSD plot.

the 30% high and 70% low PDS. This describes theseverity of the vibration levels for the entire spec-trum. In addition the high and low for the climaticdata (temperature and humidity) is also presentedfor each trip.

The data shows that the air ride truck vibrationlevels are significantly lower than the leaf springtruck vibration levels. The highest Grms for the 30%high leaf spring data shows a Grms level of 0.89G.The highest Grms for the 30% high air ride datashows a Grms level of 0.50G. Based on previousstudies conducted by the authors at Michigan StateUniversity, these findings are similar where theleaf spring vibration levels are at least 50% higherthan air ride vibration levels.2

Also during the preliminary data analysis thelateral and longitudinal levels in these shipmentswere extremely low (<0.1G) as compared to thevertical vibration levels. These findings are similarto other truck vibration measurement studies donefor commercial shipments on US highways.4

Also from the data in Figures 21 and 22, the leafspring composite spectrum has a 30% high level of0.659 Grms and a 70% low level of 0.354 Grms. Theair ride composite spectrum has a 30% high levelof 0.283 Grms and a 70% low level of 0.146 Grms.Again, this shows that the leaf spring suspensionvibration levels are significantly higher than airride vibration levels.

The next two sections are recommended testprotocols for air ride and leaf spring shipments,using ASTM D4728. The tests are based on the datacollected and are designed to represent 500–1000mile shipments. In cases of longer shipments,longer test duration needs to be used. It is recom-mended to use an additional 60min of test time forevery 250–500 miles of distance travelled. This 60min of additional testing may be performedwith 40min at low level and 20min at high level.

Test protocol (leaf spring)

The data collected in truck shipments 1, 2, 9, 11 and14 were used to develop test profiles for simulat-ing vertical vibration levels in trailers with leafspring suspensions. Two composite PDS weredeveloped, based on all the data collected for leafspring trailers. The first represents the 30% high

levels of all data collected. The second representsthe 70% low of all the data collected. Based onthese spectra, a vibration test was developed asdescribed below.

1. Conduct the random vibration test, usingASTM D 4728.

2. Place a test rack on the electro-hydraulic vibra-tion table and subject it to a 60min randomvibration test using the 70% low vibration spec-trum (leaf spring). Restrict any side travel of therack by using fixtures.

3. Continue with a 30min random vibration testusing the 30% high vibration spectrum (leafspring). Restrict any side travel of the rack byusing fixtures.

4. Make all observations for the rack, packagingmethod, strapping, shifting of glass and break-age during the test.

Test protocol (air ride)

The data collected in the truck shipments 3, 4, 5, 6,7, 8, 10 and 12 were used to develop test profilesfor simulating vertical vibration levels in trailerswith air ride suspensions. Two composite PDSwere developed based on all the data collected forair ride trailers. The first represents the 30% highlevels of all data collected. The second representsthe 70% low of all the data collected. Based onthese spectra, a vibration test was developed asdescribed below. Trip 13 data were not used in thisanalysis, due to instrumentation error for thevibration channel.

1. Conduct the random vibration test, usingASTM D 4728.

2. Place a test rack on the electro-hydraulic vibra-tion table and subject it to a 60min randomvibration test, using the 70% low vibration spec-trum (air ride). Restrict any side travel of therack by using fixtures.

3. Continue with a 30min random vibration testusing the 30% high vibration spectrum (airride). Restrict any side travel of the rack byusing fixtures.

4. Make all observations for the rack, packagingmethod, strapping, shifting of glass and break-age during the test.



Climatic data for glass shipments

Based on these shipments, which occurredbetween October 2001 and January 2002, the tem-perature levels varied in the range 34.6–72.9°F. The relative humidity levels varied in the range21.5–72.8%.

Summary spectra

Table 3 shows summary spectra that can easily beprogrammed in random vibration controllers tosimulate vibration conditions discussed in thispaper for air ride suspension truck shipments.Table 4 shows summary spectra for leaf spring sus-pension truck shipments.

REFERENCES

1. Singh SP, Marcondes J. Vibration levels in commer-cial truck shipments as a function of suspension andpayload. J. Test. Evaluat. 1992; 20(6): 466–469.

2. Pierce C, Singh SP, Burgess G. A comparison of leafspring to air cushion trailer suspensions in the trans-portation environment. J. Packag. Technol. Sci. 1992;5: 11–15.

3. Tustin W, Mercado R. Random Vibration in Perspec-tive. Tustin Institute of Technology, Santa Barbara,USA, 1984.

4. Singh SP, Antle J, Burgess G. Comparison betweenlateral, longitudinal and vertical vibration levels incommercial truck shipments. J. Packag. Technol. Sci.1992; 5: 71–75.



Table 3. Summary spectra breakpoints for airride suspension truck

Power density level (G2/Hz)

Frequency (Hz) 70% Low 30% High

1 0.00242 0.000622 0.00446 0.001526 0.00013 0.000039 0.00483 0.00282

10 0.00081 0.0003420 0.00039 0.0001230 0.00013 0.0000340 0.00027 0.0000650 0.00158 0.0001560 0.00019 0.0000370 0.00034 0.0000980 0.00159 0.0004590 0.00117 0.00020

100 0.00028 0.00012200 0.00006 0.00001

Table 4. Summary spectra breakpoints for leafspring suspension truck

Power density level (G2/Hz)

Frequency (Hz) 70% Low 30% High

1 0.00048 0.000182 0.00319 0.000633 0.01820 0.006256 0.00014 0.000059 0.00202 0.00108

12 0.00028 0.0000720 0.00195 0.0002430 0.00482 0.0005840 0.00057 0.0000950 0.00430 0.0007560 0.00296 0.0008170 0.00161 0.0005780 0.00153 0.0007390 0.00177 0.00081

100 0.00432 0.00159200 0.00026 0.00008

measurement and analysis of us truck vibration for leaf spring and air ride suspensions, and...

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