FMVSS202a Dynamic Lear 09 0324

8/12/2019 FMVSS202a Dynamic Lear 09 0324

1/15

INFLUENCE OF SEATBACK CONTENT AND DEFLECTION ON FMVSS 202A DYNAMIC RESPONSEGerald LockeEric VeineLear CorporationAndrew MerkleMichael KleinbergerIan WingJohns Hopkins University Applied Physics LaboratoryUnited States of AmericaPaper Number 09-0324

ABSTRACT

Automotive seat design requires knowledge of thestructural response of the seat under various impactconditions as well as understanding the complexinteractions between an occupant, seat content andrestraint systems. For the case of rear impactcollisions, the seat becomes the primary restraintwhile seatback and head restraint design becomeincreasingly important in mitigating the risk ofoccupant injury. This study involved the testing ofthree different seatback designs under FMVSS 202adynamic conditions to determine the effects ofseatback comfort content on occupant response andinjury risk measures. Controlled variables includeseatback content and seatback stiffness. Threedifferent recliner stiffness values were simulated thatresulted in nominal seatback rotation angles of 5, 10and 15 degrees. Additionally, three different lumbarsupport mechanisms were tested, including a staticsuspension, horizontal lumbar support and vertical

lumbar support. Results from the 18 tests conductedare presented and analyzed.

It is expected that the various comfort content willaffect torso penetration into the seatback, altering thetorso angle and therefore influence the resulting headwith respect to torso angle. It is determined thatseatback rotation (stiffness) and backset are

predictors of head angle and that lumbar support typeand foam stiffness affect the backset. The time ofmaximum head with respect to torso angle(determined as the critical event time) is influenced

by seatback stiffness, lumbar support type and lower

torso rebound. Both seatback stiffness and lumbartype are found to be good predictors of torso penetration. The amount of torso penetration and therebound effect on torso angle at the critical time inthe event are key findings. None of the independentfactors are found to have a significant influence onHIC.

INTRODUCTION

Although injuries associated with low speed rearimpacts are typically minor, the annual societal costassociated with these injuries in the US has beenestimated at approximately $2.7 billion by the

National Highway Traffic Safety Administration(NHTSA) [1]. Based on epidemiological data andscientific research, the NHTSA published theupgraded FMVSS 202a head restraint standard in2006 [1], which provides a dynamic option for theevaluation of vehicle seats that might perform betterin rear impact collisions than their geometricmeasures may indicate.

Numerous scientific studies have reported connection between neck injury risk and seat design parametersduring a rear impact [2-9]. Farmer et al. [3] foundthat active head restraints which moved higher andcloser to the occupants head during rear-endcollisions reduced injury claim rates by 14-26 percent.

Voo et al. [8] evaluated original equipmentmanufacturer (OEM) seats with active head restraintsunder dynamic test conditions to determine whetherdynamic seat performance correlated with staticgeometric positioning. Results showed that seatdesign factors influenced the dynamic performanceof the seats.

This study investigates the effects of changes incomfort content and frame stiffness (related to seatadjuster type) under the dynamic optionspecifications of FMVSS 202a. For seat design, it isimportant to recognize the difference between frame

stiffness and lumbar support system stiffness andtheir influence on torso penetration into the frame.Relative stiffness of these components affect theamount and timing of torso penetration into the seat,which in turn affect the motion of both the torso andhead.

Head displacement relative to the torso during thedynamic event is a function of head support relativeto torso support after compression of the foam

Locke 1


2/15

covering the structures in these areas. The type oflumbar support or suspension system will affect thedynamic torso angle due to localized stiffness orability to flex. The type of lumbar support can alsoaffect the H-point location and backset during theinitial dummy positioning. The manufacturingvariations of seatback and cushion foam propertiesare known to affect the H-point location, torso angleand backset. H-point height is also directly related tothe height of the head restraint. The seat frames, headrestraints, foam and trim used in this experiment wereof the same design, but with varied torso supportfeatures.

METHODOLOGY

Deceleration Sled System

The rear impact vehicle collision environment wassimulated with a Via Systems HITS Deceleration sled.The system contains a tunable hydraulic deceleratorthat absorbs the kinetic energy from the sled carriageand payload by forcing fluid through a series oforifices. The selected orifice array determines thecrash pulse experienced by the sled system.

Impact conditions - Rear impact collisions weresimulated with a deceleration tuned to the FMVSS202a Dynamic test pulse.

Adjustable Seatback Stiffness

The standard dual recliners that connect the seat

cushion frame to the seatback frame were modifiedso that they became free-pivots. Each seatback wasmodified to accommodate a C-channel frame forinterfacing with a spring-damper assembly (Figure 1)used to control seatback rotational stiffness.

The frame allowed for variable positioning of thesupport system and modifications of seatbackrotational stiffness. Spring stiffness and positionsettings for targeted seatback rotations of 5, 10 and15 degrees were selected using predictive models.The settings for the test conditions are provided inTable 1.

Table 1.Simulated recliner stiffness for desired

magnitudes of rotation

Nominal Rotation(degrees)

Recliner Stiffness(Nm/degree)

5 21910 10815 71

Figure 1. Seat system and spring-damper assembly.

Instrumentation and Data Acquisition

The coordinate system used for the Hybrid III andsled is shown in Figure 2. The dummy wasinstrumented with tri-axial accelerometer arrays atthe center of gravity (CG) of the head, torso and

pelvis. Six-axis load cells, sensing tri-axial forces andmoments, were installed in the upper and lower neck

and a three-axis load cell was placed in the lumbarspine.

Sled LeftwardDummyRightward+Y

Sled RearwardDummyForward+X

+ZSled DownwardDummyDownward

Figure 2. Sled and Hybrid III coordinate system.

Angular rate sensors were attached at the head CGand the spine at T4. An accelerometer was mountedto the sled to record the deceleration during impact.The complete list of the instrumentation used during

Locke 2


3/15

these tests is provided in Table 2. All designated polarities, filtering, and sampling rates weredetermined in accordance with SAE RecommendedPractice J211. All sensor data were collected at asampling rate of 10 kHz using an on-board TDASPro data acquisition system mounted to the sled base

plate.

Table 2.Sled and ATD instrumentation

Sensor Location Accelerometer Sled (x)

Head Contact Switch Head-Head Restraint

Angular Rate Sensor Head (y)

Angular Rate Sensor Torso (y)

Accelerometer Head CG (x,y,z)

Accelerometer Torso CG (x,y,z)

Load Cell Upper Neck (Fx,Fy,Fz,Mx,My,Mz)

Load Cell Lower Neck (Fx,Fy,Fz,Mx,My,Mz)

Load Cell Lumbar (Fx,Fz,My)

Accelerometer Pelvis (x,y,z)

High-speed Video

Video images were captured at 1000 frames persecond with one on-board and one off-board camera.The on-board camera, used for motion analysis, has aresolution of 512x512 and was mounted to provide aleft lateral view of the dummy kinematics from afixed distance of approximately 5 feet. Video

collection was synchronized with the data acquisitionsystem using both a contact switch and optical flashwithin the field of view. Examples of the capturedimages during impact are provided in Figure 3.

Figure 3. High-speed camera views at 111milliseconds for test LH15C.

Quadrant targets were attached to the ATD to allowfor motion tracking including the calculation ofangular displacement measurements and the amountof torso displacement. Key targets were attached tothe upper spine box and lower spine box to determine

torso movement. Torso penetration is defined as theamount the torso translated toward the seatbackframe with respect to the normal of the C-channellocated on the seatback frame. Targets were also

placed on the seat system, the C-channel and thesupporting A-frame.

Experimental Protocol

ATD Positioning Procedure - Proper installationof the Hybrid III into the seat system required amulti-step process. First, the seat system wasinstalled on the sled baseplate and the seat cushionand adjuster assembly was adjusted to the mid-pointof the track. A spring-damper support system wasthen installed to support the seatback. The lengths ofthe supports were adjusted to maintain a nominalSAE J826 H-point machine torso angle of 25 degreeswith respect to the vertical plane when the seat is instatic equilibrium with the H-point machine seated.FMVSS 202a specifies that the seatback angle, asdetermined by the torso angle of the installed H-pointmachine, must reside between 24.5 and 25.5 degrees.If this specification was met, we continued the

positioning procedure, if not, the H-point machinewas removed completely and the positioning

procedure was repeated.

Upon satisfying the angle specifications, the seat H- point location was measured. Next, the HeadRestraint Measuring Device (HRMD) was installedto measure backset and head-to-head restraint heightwhen it was set to the locking notch just lower than

mid-height (if there is no locking notch at mid-height), according to the specifications of FMVSS202a.

Figure 4. Measurement of Hybrid III backset andhead-to-head restraint height.

Locke 3


4/15

The H-point machine and HRMD were then removedand the 50% Hybrid III dummy was placed on theseat and positioned such that the head was level andthe dummy H-point was within 0.5 inches of themeasured seat H-point location. Initial dummy head

positioning included a measure of the head anglewith respect to horizontal, the effective backset andthe height difference between the top of the head andthe head restraint (Figure 4). The horizontal (X) andvertical (Z) H-point location of the dummy relative tothe measured seat H-point was recorded.

Test Matrix - Three seat systems were beingstudied (Table 3) with the difference betweensystems determined by the seat content in the form oflumbar support. The three seatback content typeswere categorized as vertical lumbar, horizontallumbar and static suspension systems (Figure 5).Three nominal levels of rotation (5, 10, and 15degrees) were selected for study. This results in atotal of nine test combinations. Conducting a fullfactorial experimental design and replicating it once

produced a test matrix consisting of 18 impact tests.

Table 3.Independent factors contributing to the design of

the test matrix

Factor No. Categori es

SeatbackContent

3 Static Suspension, HorizontalLumbar, Vertical Lumbar

Seatback

Rotation (deg)

3 5, 10, 15

Figure 5. Seatback content types.

The picture (Figure 5) shows the structuraldifferences between the three lumbar support systemswhich include a) static suspension, b) horizontal andc) vertical lumbar support systems from left to right.The static suspension is a wire mesh supported byvertical wires attached at the upper and lower framecross-members and two springs, one attached one-third of the distance up from the bottom of each side-member. The horizontal lumbar is a plastic strap

supported by flexible brackets attached to each frameside-member and a cable fixed to each bracket. Thevertical lumbar is a sheet metal panel supported byvertical wires attached at the upper and lower framecross-members. Some of the adjustment mechanismis between the panel and the frame lower cross-member. All adjustable lumbar supports are set to thefully retracted position for the FMVSS 202aDynamic procedure.

RESULTS AND DISCUSSION

Test Sample Measurements

Tables 4 and 5 list the H-point location and headrestraint backset and height dimensions for both theH-point machine/HRMD and Hybrid III by lumbarsupport type.

Initial frame angle - One of the main issues withfoam and trim variation, as well as differences in theway a lumbar type supports the seatback foam, is thatthis may require the seatback frame angle to bevaried in order to achieve the H-point machine torsoangle of 25 degrees. In Table 5 we can see that this isnot a problem for these tests as the initial seatbackframe angle was controlled reasonably well andvaried by a maximum 1.6 degrees for the horizontallumbar and 1.1 degrees for the static suspension andthe vertical lumbar. The Hybrid III is then positioned

by the FMVSS 208 procedure without adjusting theframe angle.

Table 4.SAE J826 and Hybrid III H-point coordinates and

SAE J826/HRMD backset and height

x z x z Backset Height(mm) (mm) (mm) (mm) (mm) (mm)

LH05A Horz. 11 -26 20 -21 63 65LH05B Horz. 16 -26 17 -31 65 65LH10B Horz. 13 -17 16 -21 63 66LH10C Horz. 22 -24 29 -26 69 67LH15B Horz. 23 -26 22 -26 63 65LH15C Horz. 22 -23 27 -22 68 72LS05A Static 8 -14 8 -20 84 69LS05B Static 9 -18 8 -23 77 75LS10B Static 7 -25 9 -27 80 74LS10C Static 17 -25 19 -24 63 69LS15B Static 7 -29 8 -33 77 69LS15C Static 16 -25 21 -25 84 69LV05C Vert. 16 -24 16 -24 76 62LV05E Vert. 20 -23 22 -28 73 69LV10A Vert. 13 -29 14 -28 79 71LV10B Vert. 16 -24 18 -22 80 70LV15A Vert. 11 -17 9 -18 72 67LV15B Vert. 10 -25 11 -31 75 71

HRMD

H-pt coordinates are with respect to the design H-point reference.

J826 H-p t HI II H-p tTestID

SeatContent

Locke 4


5/15

Table 5.Initial seatback frame angle, Hybrid III backsetand height, actual maximum seatback rotation

angle and head restraint contact time

Initial Frame Angle

HIII H/RBackset

HIII H/RHeight

Max. S/BRotation

H/R ContactTime

(degrees) (mm) (mm) (degrees) (msec)LH05A Horz. 21.9 71 52 7.5 60LH05B Horz. 22.7 84 51 7.7 65LH10B Horz. 22.4 87 55 10.5 69LH10C Horz. 23.5 85 53 10.5 68LH15B Horz. 21.9 84 50 14.4 73LH15C Horz. 22.7 77 58 13.3 76LS05A Static 23.0 108 53 7.4 72LS05B Static 22.7 104 61 7.2 70LS10B Static 23.1 108 60 10.6 74LS10C Static 22.3 88 63 10.7 65LS15B Static 22.3 101 55 13.9 76LS15C Static 23.4 105 52 14.0 74LV05C Vert. 22.9 95 52 7.8 68LV05E Vert. 22.5 104 57 7.7 68LV10A Vert. 22.9 99 57 10.4 69LV10B Vert. 23.6 111 63 10.4 77LV15A Vert. 22.6 96 55 14.3 75

LV15B Vert. 22.5 94 60 13.6 73

TestID

SeatContent

Backset - The backset and height of these seatswere not varied by experimental design. Thedifferences are caused by a combination of foam

properties, lumbar support type and initial seatbackframe angle. The mean backsets in Table 6 arecalculated by lumbar support type. Lumbar typeappears to be the dominant factor for influencing

backset where the horizontal lumbar and staticsuspension have the smallest and largest backsets,respectively.

Table 6.Backset mean by lumbar support type

Lumbar Support Type Backset mean (mm)Horizontal Lumbar 81Static Suspension 102 (105 without LS10C)

Vertical Lumbar 100

Referring to Tables 4 and 5, one particular seat backset, LS10C, stands out as being well below themean of the other five static suspension seats. It is ofthe same design, but the seatback foam wasmanufactured at a later date. This is an example of

the manufacturing difficulties of controlling foam properties. This foam is easier to compress with theH-point machine and Hybrid III upper torso. Theupper torso (shoulders) and lower torso (top oflumbar sine) are approximately 20 mm and 10 mmcloser to the seatback frame than LS10B, respectively,as judged by the backset and H-point data. This willalso be seen in the torso penetration data later in thediscussion.

Head contact time - The head contact time withthe head restraint in Table 5 was found to dependupon backset and frame stiffness. The head restraintcontact time increases as frame stiffness decreases forall lumbar types. For greater frame stiffness, thecontact time increases with a backset increase. Thedifference in head contact time relative to backsetappears to diminish as the frame stiffness decreases.

The Hybrid III head restraint height, referenced downfrom the top of the head, differs by a maximum 13millimeters for all tests. This difference is caused byseat cushion foam property and head restraintdimensional variations. It will influence the results ifthe head center-of-gravity becomes higher than thetop of the head restraint structure due to ramping ofthe dummy upward with respect to the seatback.Ramping of the dummy may be affected by thestiffness of the lumbar support system and seatbackrotation angle which will be discussed.

Acceleration pulse - The acceleration pulses for alltests are shown in Figure 6. The onset of allaccelerations and the peak values, with a fewexceptions, are within the required corridor. Therepeatability is acceptable for this test series,however two pulses, LS05B and LH15C, show asignificant early reduction in magnitude before the

peak and fall below the corridor. All pulses areslightly long in time duration.

Figure 6. Sled pulses for all tests.

Table 7 lists the impact velocities and the peakdeceleration for all tests. The effect of the low pulseswill be considered during the discussion. The initialdummy positioning and the backsets for tests LS05Band LH15C were very similar to their respectiverepeat tests. The torso angles were lower and thehead angles were considerably lower, resulting in

Locke 5


6/15

reduced head with respect to torso rotation (H-Trotation). This will be discussed in greater detail inthe following sections.

Table 7.Sled acceleration peaks and velocities

Test ID Impact Vel. (km/h) Peak Decel. (g)LH05A 17.3 9.0LH05B 17.5 9.3LH10B 17.4 9.2LH10C 17.8 9.4LH15B 17.7 9.7LH15C 16.3 7.9LS05A 17.2 9.1LS05B 16.6 8.6LS10B 17.3 9.3LS10C 17.7 9.5LS15B 17.4 9.2LS15C 17.7 9.4LV05C 17.4 9.3LV05E 17.3 8.9

LV10A 17.3 9.4LV10B 17.3 9.0LV15A 17.8 9.7LV15B 17.0 8.8

Seatback rotation - Figure 7 shows that theactual seatback rotation angles are above the 5 and 10degree targets and below the 15 degree target, but arereasonably repeatable. The largest variation for thesame type of test is 1 degree for the horizontallumbar at 15 degrees of rotation and is likely caused

by the low pulse in LH15C. The spacing of theseresponses clearly delineates three discrete

populations for investigating the influence of

seatback stiffness.

6

7

8

9

10

11

12

13

14

15

4 6 8 10 12 14 16

Nominal S/B Angle (degrees)

M a x

S / B A n g

l e ( d e g r e e s

)

Horizontal

Suspension

Vertical

Figure 7. Actual maximum seatback rotationangles.

Note that the data used throughout the balance of thisdiscussion is motion analysis data. Rigidly mountedquadrant targets were used in all cases rather thanquadrant targets attached to flexible seat trim.Angular rate sensors were used to derive the head andtorso angles and compared to motion analysis results.

This comparison can be found in the appendix. Thedifferences are acceptable and motion analysisincludes additional data such as seatback rotation,upper and lower torso initial distance from theseatback frame, penetration towards the frame, x- andz-translation and head restraint angular displacement.

Figure 8 is the 15 degree seatback rotation time-history for all lumbar types and shows that the rate ofrotation is greater for the horizontal lumbar which isthe stiffest lumbar type. The more flexible staticsuspension and vertical lumbar have the lowest rate.This effect can be seen for all seatback rotationangles, but is less pronounced as the seatbackstiffness increases.

Motion Analysis - 15 degree Seatback Rotation All Lum barTyp es

-16

-14

-12

-10

-8

-6

-4

-2

0

2

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S / B A n g

l e ( d e g r e e s

)

LH15B S/B Angle

LH15C S/B Angle

LS15B S/B Angle

LS15C S/B Angle

LV15A S/B Angle

LV15B S/B Angle

Figure 8. 15 degree seatback rotation for all

lumbar types.

Head restraint angular displacement - Figure 9shows the head restraint angular displacement

relative to the seatback frame at the time ofmaximum H-T rotation. For greater seat stiffness, anincrease in head restraint angular displacementrelative to the seatback frame is observed. Thedisplacement is lower for the horizontal lumbar andis likely related to the greater seatback rotation rate.

2

3

4

5

6

7

6 8 10 12 14

S/B Angle @ Max H wrt T Angle Time (degrees)

H / R

A n g

l e ( d e g r e e s

)

H/R Angle HORZ

H/R Angle SUSP

H/R Angle VERT

Figure 9. Head restraint angular displacement @maximum H-T rotation time.

Locke 6


7/15

Locke 7

HIC 15 The HIC 15 values in Table 8 are very lowcompared to the FMVSS 202a limit of 150. Theconstruction of the head restraints consists of a semi-rigid expanded polypropylene core attached to a 10millimeter diameter solid frame (and posts) covered

by 20 mm of polyurethane foam and a trim cover.The stiff head restraint construction used in theexperiments had no detrimental effect. Statisticalanalyses showed that seatback rotation and lumbarsupport types were not significant in influencing HIC.

Table 8.HIC 15 Values

Test ID HIC 15 LH05A 36LH05B 38LH10B 29LH10C 34LH15B 41LH15C 29

LS05A 40LS05B 31LS10B 34LS10C 29LS15B 36LS15C 42LV05C 31LV05E 39LV10A 33LV10B 38LV15A 36LV15B 37

Hybrid III ramping The z-directiondisplacement relative to the seatback frame will show

the effect of lumbar type and seatback rotation onHybrid III ramping. The z-axis is parallel to theseatback frame and rotates with the seatback.Increased ramping may reduce the effectiveness ofthe head restraint, depending on the initial height.Figure 10 shows the upper torso z-directiondisplacement for all lumbar types at the 15 degreeseatback rotation angle.

-10

0

10

20

30

40

50

60

0 0.02 0.04 0.06 0.08 0.1 0.12 0.1

Time (seconds)

U .

T o r s o

Z - D

i s p

l . ( m m

)

4

LH15B U Torso Z

LH15C U Torso Z

LS15B U Torso Z

LS15C U Torso Z

LV15A U Torso Z

LV15B U Torso Z

Figure 10. Upper torso z-axis displacement - 15degree seatback rotation all lumbar types.

The 15 degree seatback rotation proves to generatethe greatest ramping, but only a few millimeters morethan other cases. The static suspension is slightlygreater in magnitude and peaks slightly earlier. At allseatback rotation angles, all lumbar types allowessentially the same amount of ramping (seeappendix).

Hybrid III segment angles - The Hybrid III headand torso rotation time-histories are used to calculatethe maximum head with respect to torso rotation (H-T rotation). This angle is the maximum difference

between the head and torso rotation at any point intime during the event, up to 200 milliseconds. Thetime of maximum H-T rotation is studied for theinfluence of lumbar support type and seatbackrotation. Much of the data presented will be at thiscritical time.

Figure 11 shows that the changes in head rotation ateach seatback stiffness level are generally greaterthan the increase in seatback rotation at the time ofmaximum H-T rotation. The exception is for thevertical lumbar for which the rate of head rotationincrease is approximately equivalent to that ofseatback rotation. This implies that head supportgenerally degrades as seatback rotation increasesalthough the head restraint angular displacementfindings (Figure 10) show that it has lessdisplacement at greater seatback angles.

16

18

20

22

24

26

28

30

6 8 10 12 14


H e a

d A n g

l e ( d e g r e e s

)

Head Angle HORZ

Head Angle SUSP

Head Angle VERT

Figure 11. Head angle @ maximum H-T rotationtime.

The static suspension shows the largest variation atthe ten degree seatback rotation. The lowest headangle is test LS10C seat which has a backset muchsmaller than the average of the other staticsuspension seats. The horizontal lumbar consistentlyhas the lowest head angles and it also has the lowestaverage backset of all lumbar types. However,

backset is not the only contributor to head support.The distance of shoulder penetration will also affect


8/15

head angle. An analysis of upper torso penetration isconducted in the following sections.

Similar to observations with head rotation, Figure 12shows that changes in torso angle for each seatbackstiffness condition increase at a rate greater than thatof seatback rotation at the time of maximum H-Trotation. There does not appear to be a significantinfluence of lumbar support type on torso angle. Thevertical lumbar does exhibit a slightly greater torsoangle, particularly at the 10 degree seatback rotation.The distance of the upper and lower torso penetrationat critical time as well as the rebound will beanalyzed to help understand this as well as the affecton head support.

6

8

10

12

14

16

18

20

6 8 10 12 14


T o r s o

A n g

l e ( d e g r e e s

)

Torso HORZ

Torso SUSP

Torso VERT

Figure 12. Torso angle @ maximum H-T rotationtime.

Figure 13 shows the time-history of the Hybrid IIIsegment angles for the static suspension repeat tests

at 10 degree seatback rotation. These tests representthe greatest difference in head angles between repeatsdue to the LS10C backset (Table 5) as discussedearlier. The maximum head angle occurs just aftercritical time and just before the time of maximumseatback rotation. The maximum torso angle occurswell after maximum seatback rotation. Theseobservations apply to all tests.

-30

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LS10B Head AngleLS10B Torso AngleLS10B Head wrt TorsoLS10C Head Angl eLS10C Torso AngleLS10C Head wrt Torso

Figure 13. HII segment angles for the staticsuspension - 10 degree seatback rotation.

Torso Penetration - The starting point of eachcurve is the initial distance of the torso target to a lineon the structure attached to the seatback frame and

parallel to the seatback frame. The x-axis is normal tothe seatback frame and rotates with the seatback. Themagnitude becomes smaller as the torso displacestoward the seatback frame.

Figure 14 shows the upper torso penetration towardsthe seatback frame of the static suspension tests at allseatback rotation angles. At the critical time, theupper torso has penetrated to its maximum for the 5and 10 degree seatback rotation angles. While all

penetrations are fairly stable at this time, the 15degree rotation tests have not yet reached theirmaximum and the 5 degree rotation is in reboundshortly after. This is typical for all lumbar types.

260

270

280

290

300

310

320

330

340

350

360

370

380

390

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (sec)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)

LS05A U Torso XLS05B U Torso X

LS10B U Torso XLS10C U Torso XLS15B U Torso XLS15C U Torso X

Figure 14. Upper torso x-direction penetration -static suspension - all seatback rotation angles.

The LS10C initial position shows why the backset issmaller for this test. The LS10C upper torso

penetration is deeper than LS10B, reinforcing the lowfoam stiffness observation.

Figure 15 shows the upper torso penetration for alltests at the time of maximum H-T rotation. The upperseatback should present less resistance to the torso asit rotates at the greater angles since more energy is

being absorbed by the spring-damper controlling therotation. The horizontal lumbar is most representativeof this theory. However, the static suspension andvertical lumbar both show an increase in penetration

for the 10 and 15 degree seatback rotations. Thisshould result in lower head angles (Figure 11), butdoes not because the head restraint angulardisplacement (Figure 9) is also greater. The staticsuspension and vertical lumbar both allow more forceto be distributed to the upper seatback due to theirinherent flexibility and method of attachment to theframe. This distribution of force along the seatbacksupports the finding of the lower rate of seatbackrotation (Figure 8).

Locke 8


9/15

260

265

270

275

280

285

290

295

300

305

310

6 8 10 12 14

S/B Angle @ Max H wrt T Time (degrees)

D i s t a n c

e f r o m

F r a m e

R e

f . ( m m

)

Upper Torso HORZ

Upper Torso SUSP

Upper Torso VERT

Figure 15. Upper torso penetration @ maximumH-T rotation time.

Figure 16 shows that the lower torso is in rebound atthe time of maximum H-T rotation for the staticsuspension tests at all seatback rotation angles. Thisis typical for all lumbar types.

260270280290300310320330340350360370380390400410420

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (sec)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)

LS05A L Torso XLS05B L Torso XLS10B L Torso XLS10C L Torso XLS15B L Torso XLS15C L Torso X

Figure 16. Lower torso x-direction penetration -

static suspension - all seatback rotation angles.

It is a key finding that the torso angle is increasing atrelative to the seatback frame at the time ofmaximum H-T rotation. Since the upper torsoremains at a stable or increasing penetration, thislower torso rebound is a major factor of torso angleand is likely susceptible to changes in the stiffnessand energy return of a lumbar support system. If thelower torso rebound occurs earlier or is larger inmagnitude, the head with respect to torso angle will

be reduced.

Both torso penetration plots (Figures 14 and 16) alsoshow the initial distance of the torso targets to theseatback frame reference line. These targets are at thesame locations on the dummy and the seatback for alltests. This data shows the variation in dummy set-updue to what is believed to be foam variation, notmechanical or dimensional differences in the staticsuspensions. Foam stiffness is known to vary withtemperature and humidity differences during themanufacturing process. The torso penetration plots

for the horizontal and vertical lumbar supports areavailable in the appendix for review.

The lower torso x- and z-axis displacement at the 10degree seatback rotation in Figure 17 shows somedifferences in displacement characteristics of lumbartypes. The horizontal lumbar is able to restrain theHybrid III pelvis/lumbar while the static suspensionand vertical lumbar provide restraint to a lower extent.This explains why the static suspension and verticallumbar upper torso continues to penetrate. This datais truncated at the time of maximum H-T rotation.

-210

-200

-190

-180

-170

-160

-150

-140

-130

260270280290300310320330340350360370380

L. Torso X-Displ. (mm)

L .

T o r s o

Z - D

i s p

l . ( m m

)

LH10B L Torso X,ZLH10C L Torso X,ZLS10B L Torso X,ZLS10C L Torso X,ZLV10A L Torso X,ZLV10B L Torso X,Z

Figure 17. Lower torso x- & z-axis displacement@ 10 degree seatback rotation all lumbar types.

The maximum lower torso penetration for all tests inFigure 18 shows that the horizontal lumbar has thehighest resistance to penetration at all seatbackrotations. The static suspension is the least resistantto torso penetration with the exception of the 15

degree seatback rotation where it is the same as thevertical lumbar. The seatback frame lower cross-member is contacted in all tests as evidenced by

permanent deformation that increases in magnitudewith seatback stiffness. The resistance to lower torso

penetration by the horizontal lumbar shows that ittransfers more force to the lower portion of theseatback frame which increases the rate of seatbackrotation (Figure 8).

260

270

280

290

300

310

320

330

6 8 10 12 14 16

Max S/B Angle (degrees)

D i s t a n c e

f r o m

F r a m e R

e f . ( m m

)

Lower Torso HORZLower Torso SUSPLower Torso VERT

Figure 18. Maximum lower torso penetration.

Locke 9


10/15

The lower torso rebound from maximum penetrationat the time of maximum H-T rotation in Figure 19shows that rebound increases as the seatback rotationincreases. There is little difference in the magnitudeof all lumbar types. The amount of rebound appearsto be mainly a function of time. This time is thedifference in the time of maximum penetration andthe time of maximum H-T rotation. If the timedifference increases as the seatback rotation increases,then there is more time for lower torso rebound andthis will result in an increase of the torso angle.

5

10

15

20

25

30

35

40

6 8 10 12 14

S/B Angle @ Max H wrt T An gle Time (degrees)

L o w e r

T o r s o

R e

b o u n

d ( m m

)


Figure 19. Lower torso rebound @ maximum H-T rotation time.

Since the horizontal lumbar has no energy storageand return properties and the lower torso still exhibitssubstantial rebound, rebound must be a mainly afunction of time rather than the mechanical propertiesof the lumbar type. Table 9 lists the time duration ofthe rebound from maximum lower torso penetration

to the time of maximum H-T rotation.

Table 9.Time duration of lower torso rebound

Test ID Max.PenetrationTime (msec)

Max H-TRotation Time

(msec)

ReboundDuration(msec)

LH05A 83 98 15LH05B 83 98 15LH10B 82 103 21LH10C 80 100 20LH15B 79 104 25LH15C 84 109 25LS05A 87 102 15

LS05B 87 103 16LS10B 85 107 22LS10C 82 97 15LS15B 84 110 26LS15C 82 111 29LV05C 86 100 14LV05E 85 102 17LV10A 82 103 21LV10B 85 105 20LV15A 83 107 24LV15B 84 112 28

The lower torso penetration peaks earliest at the 5degree seatback rotation for the horizontal lumbar,otherwise all results are similar. The time ofmaximum H-T rotation is delayed as seatbackstiffness decreases, therefore the time duration oflower torso rebound increases as seat rotationincreases. The static suspension and the verticallumbar have a slightly longer rebound time durationat the 15 degree seatback rotation.

For the lower torso penetration at the time ofmaximum H-T rotation (Figure 20), the horizontallumbar, with no significant spring characteristics, isfarthest from the frame. The static suspensionappears to have more energy return due to the springtension at mid-height of the frame. At the 15 degreeseatback rotation, it reduces the distance between itand the horizontal lumbar at maximum penetration.The vertical lumbar, which has long spring-steel wiresupports, shows a similar characteristic at the 15degree seatback rotation.

270

280

290

300

310

320

330

340

350

360

6 8 10 12 14

S/B Angle @ Max H wrt T Angle (degrees)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)


Figure 20. Lower torso penetration @ maximumH-T rotation time.

The maximum H-T rotation in Figure 21 is one of thecompliance requirements of FMVSS 202a with atwelve degree maximum. The largest variations occurwith the static suspension and the horizontal lumbarat 10 and 15 degree seatback rotations, respectively.The LS10C is the lowest due to the low head anglecaused by the smaller backset (Table 5) and lowseatback foam stiffness described earlier. The lowesthorizontal lumbar point is LH15C and is due to the

low head angle caused by the low pulse (Table 7).

Locke 10


11/15

5

6

7

8

9

10

11

12

13

6 8 10 12 14


H w r t

T A n g

l e ( d e g r e e s

)

Head wrt Torso HORZ

Head wrt Torso SUSP

Head wrt Torso VERT

Figure 21. Maximum H-T rotation.

Considering the small differences in torso angles(Figure 12), the static suspension generally has thegreatest maximum H-T rotation which is caused bygreater head angles (Figure 11). This is mainlyattributed to larger backsets caused by the most

prominent seatback foam support (Table 6). Thevertical lumbar provided seatback foam supportsimilar to the static suspension and has similar

backsets. Given the similar head angles and slightlygreater torso angles, it performed slightly better thanthe static suspension. The horizontal lumbar has thelowest head with respect to torso angles because ofthe lower head angles. This is attributed toapproximately 20 millimeter smaller backsets caused

by the least prominent seatback foam support whichoffsets the approximate 10 millimeter reduction inshoulder penetration.

CONCLUSIONS

During test set-up, the backset is affected by bothlumbar type and foam stiffness variation. The staticsuspension provided more prominent support of theseatback foam and tended to increase the backset.The largest foam variation, a reduction in foamstiffness in one static suspension test, caused asignificant reduction in backset. During that testevent, the torso penetration was also the greatest ofall tests. This resulted in the earliest head contacttime, the lowest head rotation and the lowest H-Trotation (for a valid pulse). For all other tests withreasonably consistent foam properties, the static

suspension tends to have the highest H-T rotation.Therefore, seatback foam properties have asignificant influence on head support with morecompliant foam improving head support.

The HIC 15 is low for all tests and did not appear to beaffected by the stiff head restraint construction or thecontrolled parameters of seatback rotation or lumbarsupport type.

The head restraint angular displacement relative tothe seatback frame increases as seatback stiffnessincreases, however the horizontal lumbar tests havelower head restraint displacement and head angle.The horizontal lumbar provides greater restraint ofHybrid III pelvis/lumbar displacement due to theattachment at the frame side-members and relativeinability to flex rearward. The horizontal lumbarincreases the rate of seatback rotation, reducing theupper torso penetration, head restraint displacement,head rotation and H-T rotation. Therefore, a stifflumbar support attached in a manner that limitsrearward displacement reduces maximum H-Trotation.

Ramping of the Hybrid III, which may reduce theeffectiveness of the head restraint, was notsignificantly effected by lumbar support type orseatback stiffness.

Head angle increases at a greater rate than thecontrolled maximum seatback rotations, regardless ofthe head restraint angular displacement finding.Torso angle also increases at a greater rate than thecontrolled maximum seatback rotations. This is dueto stable upper torso penetration and lower torsorebound at the time of maximum H-T rotation. Lowertorso rebound is found to be a mainly a function oftime rather than a function of the energy returncharacteristics of lumbar type. The maximum torso

penetration is a function of lumbar support stiffness,foam stiffness and seatback stiffness. The maximumtorso penetration and the amount of time for lower

torso rebound determine the torso angle at the time ofmaximum H-T rotation.

In this experiment, the horizontal lumbar proved tohave the highest resistance to lower torso penetration.Maximum lower torso penetration time is essentiallythe same for all lumbar types and seatback stiffnesswith only a slight delay for the more flexible lumbarsupport types. The time to maximum H-T rotationincreases as the maximum seatback rotation increases.This results in greater lower torso rebound time anddistance as the maximum seatback rotation increases.Therefore, there is an increase in torso angle at

maximum H-T rotation time as the maximumseatback rotation increases. This results in a lowermaximum H-T rotation.

RECOMMENDATIONS

Head support is reduced as seatback rotationincreases as evidenced in the head angle discussion.Therefore, decreasing the seatback stiffness (addingto lower torso rebound time) to increase torso angle is

Locke 11


12/15

probably neutralized at some undeterminedmaximum seatback rotation. If comfort specificationsallow, it would be recommended to reduce the

backset (to reduce head angle) and/or stiffen thelumbar support mechanism to reduce lower torso

penetration (to increase torso angle) at the criticaltime to improve the Hybrid III maximum H-Trotation result.

A follow-up study will be done to analyze the HybridIII neck forces and moments collected during thisexperiment.

STUDY LIMITATIONS

Listed are some notable limitations of this study: The width of the seatback frame may affect the

ability of the torso to penetrate regardless of thelumbar support system.

The stiffness of the head restraint posts and theattachment to the seatback frame may affect theamount of head restraint angular displacementrelative to the seatback.

The amount and properties of compressible foamcovering the seat structure.

The construction of the head restraint, backsetand height.

The type of anthropomorphic test device(dummy), particularly spine flexibility, mayaffect the results.

All of these seat design factors vary with seatmanufacturer and vehicle model styling requirements.

Other rear impact simulation protocols specifydifferent crash pulses and dummy types. Theobservations reported here are directionally correctfor the Hybrid III dummy, but the magnitude willvary with other seat types.

ACKNOWLEDGEMENT

The authors would like to thank Arjun Yetukuri,Liming Voo, Howard Conner and Bethany McGeefor their contributions to the planning and executionof this test series.

REFERENCES

[1] NHTSA Final Rule. Federal Motor VehicleSafety Standards: Head Restraints. Docket No.

NHTSA-2004-19807, RIN 2127-AH09, 2006.

[2] Eichberger A, Geigl BC, Moser A, Fachbach B,Steffan H, Hell W, Langwieder K. Comparison ofDifferent Car Seats Regarding Head-NeckKinematics of Volunteers during Rear End Impact,

International IRCOBI Conference on theBiomechanics of Impact, Dublin, September, 1996..

[3] Farmer, C., Wells, J., Lund, A., Effects of HeadRestraint and Seat Redesign on Neck Injury Risk inRear-End Crashes, Report of Insurance Institute forHighway Safety, October, 2002.

[4] Kleinberger M, Voo L, Merkle A, SzczepanowskiR, and McGee B. A comparative study of dummysensitivity to seat design parameters. 20th EnhancedSafety of Vehicles Conference, Paper No. 07-0366,Lyon, France, June, 2007.

[5] Kleinberger M, Voo LM, Merkle A, Bevan M,Chang S, The Role of Seatback and Head RestraintDesign Parameters on Rear Impact OccupantDynamics, Proc 18 th International TechnicalConference on the Enhanced Safety of Vehicles,Paper #18ESV-000229, Nagoya, Japan, May 19-22,2003.

[6] Olsson, I., Bunketorp, O., Carlsson G.,Gustafsson,C., Planath, I., Norin, H., Ysander, L. An In-DepthStudy of Neck Injuries in Rear End Collisions, 1990International Conference on the Biomechanics ofImpacts, Lyon, France, September, 1990.

[7] Svensson, M., Lovsund, P., Haland, Y., Larsson,S. The Influence of Seat-Back and Head-RestraintProperties on the Head-Neck Motion during Rear-Impact, 1993 International Conference on the

Biomechanics of Impacts, Eindhoven, Netherlands,September, 1993.

[8] Voo L, McGee B, Merkle A, Kleinberger M, andKuppa S. Performance of seats with active headrestraints in rear impacts. 20th Enhanced Safety ofVehicles Conference, Paper No. 07-0041, Lyon,France, June, 2007.

[9] Voo LM, Merkle A, Wright J, and KleinbergerM: Effect of Head-Restraint Rigidity on WhiplashInjury Risk, Proc Rollover, Side and Rear Impact(SP-1880), Paper #2004-01-0332, 2004 SAE World

Congress, Detroit, MI, March 8 - 11, 2004.

Locke 12


13/15

APPENDIX

Seatback Rotations

Motion Analysis - 5 degree Seatback Rotation All Lum bar Ty pes

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S / B A n g

l e ( d e g r e e s

)

LH05A S/B Angle

LH05B S/B Angle

LS05A S/B Angle

LS05B S/B Angle

LV05C S/B Angle

LV05E S/B Angle

Motion Analysis - 10 degree Seatback Rotation All Lum bar Ty pes

-12

-10

-8

-6

-4

-2

0

2

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S / B A n g

l e ( d e g r e e s

)

LH10B S/B Angle

LH10C S/B Angle

LS10B S/B Angle

LS10C S/B Angle

LV10A S/B Angle

LV10B S/B Angle

Angular Rate Sensor and Motion Analysis

Test ID

Gyro HeadRotation

(degrees)

MA HeadRotation

[degrees]

Gyro TorsoRotation

(degrees)

MA TorsoRotation

[degrees]

Gyro H wrt TRotation(degees)

MA H wrt TRotation

[degrees]LH05A 18.15 18.55 10.76 11.67 10.06 9.51LH05B 18.88 19.17 11.92 13.02 9.81 8.92LH10B 22.55 23.64 16.65 17.58 9.67 9.60

LH10C 22.22 22.95 17.72 19.14 8.68 8.01LH15B 27.48 28.23 23.57 24.46 9.11 8.88LH15C 23.69 24.37 21.74 22.92 6.14 5.51LS05A 20.81 21.48 11.29 12.26 12.23 11.83LS05B 17.75 18.76 10.32 11.14 9.87 9.99LS10B 25.30 25.19 19.06 19.84 10.50 9.51LS10C 18.30 18.99 18.05 18.75 5.91 5.87LS15B 26.98 27.74 22.02 23.14 10.14 9.62LS15C 28.85 29.93 23.89 25.02 9.29 8.99LV05C 20.44 20.99 12.12 13.16 11.01 10.31LV05E 19.69 20.36 12.00 12.79 10.47 10.22LV10A 24.33 25.32 18.40 19.00 9.65 10.01LV10B 24.32 24.90 19.52 20.91 9.02 8.50LV15A 27.38 27.96 23.52 24.60 8.72 8.10LV15B 28.26 28.92 23.38 24.40 8.44 7.86

HIII-50 Segment Angles - Horizontal Lumbar Motion Analysis 5 degree Seatback Rotation

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LH05A Head AngleLH05A Torso AngleLH05A Head wrt TorsoLH05B Head AngleLH05B Torso AngleLH05B Head wrt Torso

HIII-50 Segment Angles - Horizontal Lumbar Gyro 5 degree Seatback Rotation

-20

-15

-10

-5

0

5

0 20 40 60 80 100 120 140 160 180 200

Time (msec)

A n g

l e ( d e g r e e s

)

LH05A HeadLH05A Torso

LH05A Head wrt TorsoLH05B HeadLH05B TorsoLH05B Head wrt Torso

HIII-50 Segment Angles - Horizontal Lumbar Motion Analysis 10 degree Seatback Rotation

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LH10B Head AngleLH10B Torso AngleLH10B Head wrt TorsoLH10C Head AngleLH10C Torso AngleLH10C Head wrt Torso


-25

-20

-15

-10

-5

0

5

0 20 40 60 80 100 120 140 160 180 200

Time (msec)

A n g

l e ( d e g r e e s

)

LH10B HeadLH10B TorsoLH10B Head wrt TorsoLH10C HeadLH10C TorsoLH10C Head wrt Torso

HIII-50 Segment Angles - Horizontal L umbar Motion Analysis 15 degree Seatback Rotation

-30

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LH15B Head AngleLH15B Torso AngleLH15B Head wrt TorsoLH15C Head AngleLH15C Torso AngleLH15C Head wrt Torso


-30

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LH15B HeadLH15B TorsoLH15B Head wrt TorsoLH15C HeadLH15C TorsoLH15C Head wrt Torso

Locke 13


14/15

HIII-50 Segment Angles - Static SuspensionMotion Analysis 5 degree Seatback Rotation

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LS05A Head AngleLS05A Torso AngleLS05A Head wrt TorsoLS05B Head AngleLS05B Torso AngleLS05B Head wrt Torso

HIII-50 Segment Angles - Static SuspensionGyro 5 degree Seatback Deflection

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LS05A HeadLS05A TorsoLS05A Head wrt TorsoLS05B HeadLS05B TorsoLS05B Head wrt Torso

HIII-50 Segment Angles - Static SuspensionGyro 10 degree Seatback Rotation

-30

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LS10B HeadLS10B TorsoLS10B Head wrt TorsoLS10C HeadLS10C TorsoLS10C Head wrt Torso

HIII-50 Segment Angles - Static SuspensionMotion Analysis 15 degree Seatback Rotation

-35

-30

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LS15B Head AngleLS15B Torso AngleLS15B Head wrt TorsoLS15C Head AngleLS15C Torso AngleLS15C Head wrt Torso

HIII-50 Segment Angles - Static SuspensionGyro 15 degree Seatback Angle

-30

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LS15B HeadLS15B TorsoLS15B Head wrt TorsoLS15C HeadLS15C TorsoLS15C Head wrt Torso

HIII-50 Segment Angles - Vertical Lumb ar Motion Analysis 5 degree Seatback Rotation

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LV05C Head AngleLV05C Torso Angle

LV05C Head wrt TorsoLV05E Head AngleLV05E Torso AngleLV05E Head wrt Torso

HIII-50 Segment Angles - Vertic al Lumbar Gyro 5 degree Seatback Rotation

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LV05C HeadLV05C TorsoLV05C Head wrt TorsoLV05E HeadLV05E TorsoLV05E Head wrt Torso

HIII-50 Segment Angles - Vertical Lumbar Motion Analysis 10 degree Seatback Rotation

-30

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LV10A Head AngleLV10A Torso AngleLV10A Head wrt TorsoLV10B Head AngleLV10B Torso AngleLV10B Head wrt Torso

HIII-50 Segment Angles - Vertical Lumbar Gyro 10 degree Seatback Rotation

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LV10A HeadLV10A TorsoLV10A Head wrt TorsoLV10B HeadLV10B TorsoLV10B Head wrt Torso

HIII-50 Segment Angles - Vertical Lumbar Motion Analysis 15 degree Seatback Rotation

-35

-30

-25

-20

-15

-10

-5

0

5

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (seconds)

S e g m e n

t A n g

l e ( d e g r e e s

)

LV15A Head AngleLV15A Torso AngleLV15A Head wrt TorsoLV15B Head AngleLV15B Torso AngleLV15B Head wrt Torso

Locke 14


15/15

Lower Torso Penetration - Vertcal Lumbar

270280290300310

320330340350360370380390400410420

0 0.05 0.1 0.15 0.2

Time (sec)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)LV05C L Torso XLV05E L Torso XLV10A L Torso XLV10B L Torso XLV15A L Torso XLV15B L Torso X

HIII-50 Segment Angles - Vertical Lumbar Gyro 15 degree Seatback Rotation

-30

-25

-20

-15

-10

-5

0

5

0 50 100 150 200

Time (msec)

A n g

l e ( d e g r e e s

)

LV15A HeadLV15A Torso

LV15A Head wrt TorsoLV15B HeadLV15B TorsoLV15B Head wrt Torso

Torso Displacements Upper Torso Z-Displacement5 degree Seatback Rotation

-10

0

10

20

30

40

50

60

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14Time (seconds)

U .

T o r s o

Z - D

i s p

l . ( m m

)

LH05A U Torso Z

LH05B U Torso ZLS05A U Torso Z

LS05B U Torso Z

LV05C U Torso Z

LV05E U Torso Z

Upper Torso Penetration - Horizontal Lumbar

250260270280290300310320330340350360370380390

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (sec)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)LH05A U Torso XLH05B U Torso XLH10B U Torso XLH10C U Torso XLH15B U Torso XLH15C U Torso X

Upper Torso Z-Displacement10 degree Seatback Rotation

-10

0

10

20

30

40

50

60

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

Time (seconds)

U .

T o r s o

Z - D

i s p

l . ( m m

)

LH10B U Torso Z

LH10C U Torso Z

LS10B U Torso ZLS10C U Torso Z

LV10A U Torso Z

LV10B U Torso Z

Lower Torso Penetration - Horizontal Lumbar

270280290300310320330340350360370380390400410420

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Time (sec)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)

LH05A L Torso XLH05B L Torso XLH10B L Torso XLH10C L Torso XLH15B L Torso XLH15C L Torso X

Lower Torso X- & Z-Displacement5 degree Seatback Rotation

-220

-210

-200

-190

-180

-170

-160

-150

280290300310320330340350360370380390


L .

T o r s o

Z - D

i s p

l . ( m m

)

LH05A L Torso X,ZLH05B L Torso X,ZLS05A L Torso X,ZLS05B L Torso X,ZLV05C L Torso X,ZLV05E L Torso X,Z

Upper Torso Penetration - Vertical Lumb ar

260270280290300310320330340350360370380390

0 0.05 0.1 0.15 0.2

Time (sec)

D i s t a n c e

f r o m

F r a m e

R e

f . ( m m

)LV05C U Torso XLV05E U Torso XLV10A U Torso XLV10B U Torso XLV15A U Torso XLV15B U Torso X

Lower Torso X- & Z-Displacement15 degree Seatback Rotation

-230

-220

-210

-200

-190

-180

-170

-160

-150

-140

-130

280290300310320330340350360370380390400


L .

T o r s o

Z - D

i s p

l . ( m m

)

LH15B L Torso X,ZLH15C L Torso X,ZLS15B L Torso X,ZLS15C L Torso X,ZLV15A L Torso X,ZLV15B L Torso X,Z

Locke 15

Documents

FMVSS202a Dynamic Lear 09 0324