ComputationalInjuryBiomechanics:
Ongoingprojects:
CervicalSpineDevelopment:
Acervicalspinemodelisbeingdevelopedforthestudyofinjuryandclinicalbiomechanics.Thehighlight
ofthenewmodelincludesanatomicalaccurategeometryachievedusingmulti-blockhexahedral
meshing,advancednon-linearmaterialmodelsandprovisionstoincludethevariabilitiesinpopulation
reportedinthescientificliterature.Multi-blockhexahedralmeshingtechniquegivesusertheflexibility
ofchangingthemeshdensityasrequiredbythestudybeingundertaken(static,dynamic,cyclic,etc).
Accurategeometricmodelingoftheintervertebraldiscspaceisanotherhighlightofthenewmodel.The
anatomicalvariationsincervicalintervertebraldiscfromthelumbardisc,includingthedifferencein
annulurfibrosusandtheunco-vertebraljoints,areincludedinthemodelinadditiontoallmajor
ligaments.
Far-sideinjurystudy:
Occupantsseatedclosertothestrucksideinanautomobileaccidentaredefinedasnearsidecrashes.
Onthecontrary,far-sidecrashesaredefinedaswhenoccupantsareseatedoppositetothestruckside.
Ingeneral,injurymechanismsinfar-sideimpactsarethoughttobesignificantlydifferentfromnearside
impacts. Therefore, different strategies for countermeasures to protect occupants in far-side crashes
maybenecessary.Themainobjectiveofthisstudyistodelineatetheinjurymechanismstothehead,
thorax,abdomen,andpelvis.
As a part of this ongoing study, validation and full-scale simulations were performed using restrained
GlobalHumanBodyModelConsortium(GHBMC)finiteelement(FE)modelseatedonasedanFEmodel
usingfar-sidelateralimpactcondition.A2001FordTaurusmodelwasselectedfromtheNationalCrash
AnalysisCenter(NCAC)consortiumforthecurrentstudy.Thevehiclemodelwasimpactedwitharigid
pole structure. The impact locations were at the C-pillar in the first case, at the B-pillar in the second
case,andfinally,attheA-pillarinthethirdcase.ThevehicleandtheGHBMCmodelsweredefinedan
initialvelocityof35km/h.
In general, this part of the study concluded that the vehicle and occupant kinematics varied with
differentimpactsetupsandthelatterkinematicslikelyinfluencedbyrestrainteffectiveness.Increased
restraint engagement increased the injury risk to the corresponding anatomic structure, whereas,
ineffective restraint engagement increased the occupant excursion resulting in a direct impact to the
strucksideinteriorstructures.
Figure1Vehicle,andoccupantkinematicsforhighspeedpoleA-pillar(toprow),B-pillar(middlerow),andC-pillar(bottomrow).
Thefirst,second,andthirdcolumncorrespondtotime-t=0,t=125,t=200respectively
Figure2Lateralbendingofthespine
Figure3Spineduetolapbeltforce(bluearrow),andtorsoinertia(redarrow)
Figure4Stressesanddeformationtothepelvisduetolapbeltloading
Figure5Strainstotheribcageduetolateralbending
Lowerspineinjurystudy:
Frontal crashes can produce non-horizontal loads on occupants that can induce spinal injuries like
compression and burst fractures. Even with the introduction of restraint systems that prevent
submarining, recent field data have shown the presence of injuries (more at the thoracolumbar (T-L)
junction) in restrained front seat occupants. The exact mechanism causing these injuries is still
unknown;however,itisgenerallybelievedtheyarecausedduetovariousrestraints,inputpulseshape,
constructionofcarseats,andpostureoftheoccupant.Inordertodevelopcountermeasurestoavoidor
mitigatelowerspineinjuriesitisimportanttounderstandanddelineatethemechanismscausingthese
injuries. Generally, to delineate these mechanisms, controlled experiments were preferred using
mechanical and computer based surrogates. One such computer-based surrogate that has recently
received wide attention is a finite element human body model (FEHBM), in which finite element
principles are used to model human body. In the present study, a recently developed Global Human
BodyModelConsortium(GHBMC)FEHBMwasusedtoanalyzeloadsatthelowerspineunderdifferent
loadingandboundaryconditions.
Figure6Kinematicsoftheoccupantduringrestrainedfrontalcrash
Figure7Kinematicsandposturechangeofthespineduringrestrainedfrontalcrash
Figure8CompressiveforcesattheT12-L1joint