HMMWV RolloversHMMWV Rollovers

By, Chantelle Korson

Picture taken from: Google.com

PROBLEM STATEMENTPROBLEM STATEMENT

HMMWV – not an armored vehicleHMMWV – not an armored vehicle Armor Kits (“up-armoring” or “hardening”)Armor Kits (“up-armoring” or “hardening”)

– Added sand bags, metal sheets, and plywoodAdded sand bags, metal sheets, and plywood Increased Risks Increased Risks

– Extra shrapnelExtra shrapnel– Added weight Added weight – Overload the suspensions Overload the suspensions

– RollingRolling Extra weight (up-armoring kits)Extra weight (up-armoring kits) High Centers of GravityHigh Centers of Gravity

Types of Add-on ArmorTypes of Add-on Armor

Pictures taken from: http://www.defense-update.com

General IdeaGeneral Idea

AssumptionsAssumptions

Russian TestingRussian Testing– ““Steal Pot”Steal Pot”

Limit outside factors (ground density) Limit outside factors (ground density)

Averaged/Estimated DataAveraged/Estimated Data– Vehicle specsVehicle specs– Center of Gravity Center of Gravity – Force of ExplosionForce of Explosion

Original ModelOriginal Model

CCSuspension

II1vehiclemass

RRBDampingF

1OneJunction1

0ZeroJunction1

TFTF11

OneJunction2

0ZeroJunction2

TFTF2 1

OneJunction3

0ZeroJunction3

1OneJunction4

CCSuspensionR

RRBDampingR

0ZeroJunction4

II2momentofI

TFTF3

SeSe1

1OneJunction5

MSfMSf1

MSfMSf2

SignalGenerator1 SignalGenerator2

Modified ModelModified Model

CCSuspension

II1vehiclemass

RRBDampingF

0ZeroJunction1

TFTF11

OneJunction2

0ZeroJunction2

TFTF2 1

OneJunction3

0ZeroJunction3

1OneJunction4

CCSuspensionR

RRBDampingR

0ZeroJunction4

II2momentofI

TFTF3

1OneJunction5

Integrate1

SignalGenerator1

MSeMSe1

1OneJunction1

Test ResultsTest Resultsmodel

0 2 4 6 8 10time {s}

0

0.005

0.01

0.015

output {rad}

Force=6KN-9KNRadians of Rotation = .00787-.01189

Height of Center of Gravity vs. Height of Center of Gravity vs. Rolling DisplacementRolling Displacement

Height of Center of Gravity .6m .8m 1m

Max Radians of Rotation Before Rolling 0.0106 0.00933 0.00823

Max Degrees of Rotation Before Rolling 0.609 0.535 0.471

Max Meters of Rotation Before Rolling 1.317 1.154 1.02

Max Feet of Rotation Before Rolling 4.32 3.79 3.35

Max Rotation CalculationMax Rotation Calculation

Data From SimulationData From Simulation

Height of Center of Gravity 0.6 0.8 1

Max Radians Before Rolling 0.01064 0.00933 0.00823

Force      

6KN 0.00787 0.00787 0.00787

7KN 0.00928 0.00915 0.00928

8KN 0.01061 0.01048 0.01061

9KN 0.01189 0.01181 0.01189

Height of Center of Gravity vs. Height of Center of Gravity vs. Radial DisplacementRadial Displacement

Height of Center of Gravity vs. Radail Displacement to Roll

0

0.002

0.004

0.006

0.008

0.01

0.012

0 0.2 0.4 0.6 0.8 1 1.2

Height of Center of Gravity (m)

Rad

ial

Ro

tati

on

nee

ded

to

fli

p V

ehic

le (

rad

)

ValidationValidation

Engineer from TARDECEngineer from TARDEC– ““We’ve added enough armor to survive We’ve added enough armor to survive

the explosion, but now the problem is the explosion, but now the problem is surviving the rollover.”surviving the rollover.”

Numerous Website and PublicationsNumerous Website and Publications– Roll over problems with added armorRoll over problems with added armor– Both while in motion and caused by Both while in motion and caused by

explosionsexplosions

Plan/Problems/ModificationsPlan/Problems/Modifications

Original Experiment Set UpOriginal Experiment Set Up– Change in mass = not significant Change in mass = not significant

change in rollover factorschange in rollover factors– As mass increased vehicle became As mass increased vehicle became

safersafer Simple SimulationSimple Simulation

– Basic bugsBasic bugs– MSe connected to zero junctionMSe connected to zero junction

Pulse effort with a continuous Pulse effort with a continuous displacementdisplacement

Safercar.govSafercar.gov

SSF=T/2HSSF=T/2H– T=Track Width T=Track Width – H = Height of Center of H = Height of Center of

Gravity Gravity

Average .8m Height of Average .8m Height of Center of GravityCenter of Gravity– Hummer SSF = 2.064 Hummer SSF = 2.064 – = 5 Stars= 5 Stars

ReferencesReferences Afghanistan incident Report Afghanistan incident Report 20022002 <<http://www.vcdsforces.gc.ca/boi_jowz/00Native/Anx-HDRC_Preliminary_iltis_incident_report.pdfhttp://www.vcdsforces.gc.ca/boi_jowz/00Native/Anx-HDRC_Preliminary_iltis_incident_report.pdf>> Mark D. Donahue. Implementation of an Active Suspension, Preview Controller for Improved Ride Mark D. Donahue. Implementation of an Active Suspension, Preview Controller for Improved Ride

Comfort University of California at Berkeley, 1998Comfort University of California at Berkeley, 1998 <http://vehicle.berkeley.edu/publications/ASC/mddon_msthesis.pdf><http://vehicle.berkeley.edu/publications/ASC/mddon_msthesis.pdf> The Application of Bond-Graphs to Real-Time Simulation Modeling of Vehicle DynamicsThe Application of Bond-Graphs to Real-Time Simulation Modeling of Vehicle Dynamics 27 March. 27 March.

2006 2006 <<Ulrich.kramer@fh-bieldfeld.deUlrich.kramer@fh-bieldfeld.de> and <> and <http://autolabfh-bielefeld.dehttp://autolabfh-bielefeld.de>> NATO STANAG 4569 2a to 3aNATO STANAG 4569 2a to 3a. 30 March. 2006 . 30 March. 2006 <<www.ssss.comwww.ssss.com>> Eagle Armored Vehicle, Up Armored HUMVEE, Up-Armored Humvee M1114, and Guardian Door Eagle Armored Vehicle, Up Armored HUMVEE, Up-Armored Humvee M1114, and Guardian Door

Protection For Humvee. Protection For Humvee. 30 March. 2006 30 March. 2006 <<http://www.defense-update.comhttp://www.defense-update.com>> AM General: Light Service Support Vehicle AM General: Light Service Support Vehicle 26 March. 200626 March. 2006 <<http://http://

www.amgeneral.com/vehicles_lssv_prodectinfo.phpwww.amgeneral.com/vehicles_lssv_prodectinfo.php>> Defense LinkDefense Link 30 March. 2006 30 March. 2006 <http://www.defenselink.mil/transcripts/2004/tr20041215-1801.html><http://www.defenselink.mil/transcripts/2004/tr20041215-1801.html> High Mobility Multipurpose Wheeled VehicleHigh Mobility Multipurpose Wheeled Vehicle 28 March. 2006 28 March. 2006 <http://en.wikipedia.org/wiki/Humvee><http://en.wikipedia.org/wiki/Humvee> Japan International Cooperation System Japan International Cooperation System February 2004 February 2004 <http://Jics.or.jp/jigyou/kenkyu/pdf/3GeneralRequirement.pdf.><http://Jics.or.jp/jigyou/kenkyu/pdf/3GeneralRequirement.pdf.> ADVISOR: Advanced Vehicle Simulator ADVISOR: Advanced Vehicle Simulator 30 March. 2006 30 March. 2006 <http://www.iitedu/ipro326/research.html><http://www.iitedu/ipro326/research.html> Bomb Shock Wave EstimationBomb Shock Wave Estimation. 26 March. 2006 . 26 March. 2006

<http://www.makeitlouder.com/document_bombshockwaveestimation.html><http://www.makeitlouder.com/document_bombshockwaveestimation.html> SafercarSafercar 29 March.2006 29 March.2006 <<http://www.safercar.govhttp://www.safercar.gov>>