IS 14910: Mechanical Vibration and Shock - Human Exposure - Biodynamic Coordinate Systems

20 Pages·2001·1.6 MB·English

by  Bureau of Indian Standards

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IS 14910 (2001): Mechanical Vibration and Shock - Human
Exposure - Biodynamic Coordinate Systems [MED 28:
Mechanical Vibration and Shock]
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Satyanarayan Gangaram Pitroda
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Is 14910:2001
ISO 8727:1997

Tiw%–
Indian Standard
MECHANICAL VIBRATION AND SHOCK — HUMAN
EXPOSURE — BIODYNAMICSCOORDINATE
SYSTEMS
ICS 13.160

0 BIS 2001
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, !4BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

February 2001 Price Group 7
Mechanical Vibration and Shock Sectional Committee, ME 28
NATIONAL FOREWORD
This Indian Standard which is identical with ISO 8727:1997 ‘Mechanical vibration and shock—
Human exposure — Biodynamicscoordinatesystems’issud bythe InternationalOrganization forStand-
ardization (ISO) was adopted bythe Bureau of Indian Standards on the recommendations ofthe
Mechanical Vibration and Shock Sectional Committee and approval ofthe Mechanical Engineering
DivisionCouncil.
The text of ISO standard has been approved as suitable forpublication as IndianStandard without
deviations. In the adopted standard, certain conventions are not identical to those used in Indian
Standards. Attention isespecially drawn tothe following:
a) Wherever the words ‘International Standard appear referring to this standard, they should be
read as‘IndianStandard’.
b) Comma (,) hasbeen usedasadecimal marker, whileinIndianStandards, the current practice is
to use a point (.) asthe decimal marker.
Inthis adopted standard, reference appears to the following International Standard for which Indian
Standard also exists.The corresponding IndianStandard which istobesubstituted initsplace isgiven
below along with itsdegree of equivalence for the editionindicated:
International CorrespondingIndian Degree of
Standard Standatd Equivalence
ISO 5805:1997 IS 13281:1999 Mechanical vibration Identical
and shockaffecting man — Vocabulary
The concerned technical committee has reviewed the provision of 1S0 1503:1977 ‘Geometrical
orientations and directions ofmovements’ referred inthisadopted standard and has decided that itis
acceptable for use inconjunction withthisstandard.
Forthe purpose ofdeciding whether aparticular requirement of thisstandard iscomplied with,thefinal
value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in
accordance with IS 2:1960 ‘Rules forroundingoff numerical values (revised). The number of signifi-
cant places retained inthe rounded offvalue should bethe same asthat ofthe specified value inthis

standard.
Is 14910:2001
ISO 8727:1997
Indian Standard
MECHANICAL VIBRATION AND SHOCK — HUMAN
EXPOSURE — BIODYNAMICS COORDINATE
SYSTEMS
1 Scope
This International Standard specifies anatomical and basicentric coordinate systems for biodynamical
measurements,.for reference purposes in cognate standards development, and for precisely describing human
exposure to mechanical vibration and shock. The segmental anatomical coordinate systems defined in this
InternationalStanda?dare forthe head, rootofthe neck (driving-pointforthe head and neck system), pelvis,and
hand.General principlesare statedforthe establishmentofcorrespondinganatomicalcoordinatesystemsforother
skeletal body segments. The biodynamicscoordinate systems defined in this International Standard can sewe as
frames of reference for the descriptionand measurement of bothtranslationaland rotationalvibrationand shock
motionaffectinghumans.
NOTES
1 Although defined for human subjects, these anatomical coordinate systems are adaptable, using a knowledge of
comparative anatomy, tonon-humanprimatesortootheranimalspecies whoseskeletal anatomy isrecognizablycomparable,
radiographically,withthe relevantanatomyofhumans.
2 When the need arisesforothersegmental anatomicalcoordinatesystems (e.g. forthe arm, wrist,legorfoot),these should
be defined according to correspondingprinciplesof anatomy and of standardization, and may be proposed for inclusionin
subsequentrevisionsofthisinternatio nalStandard.

3 This InternationalStandard recognizesnodifferencebetween male andfemale skeletal anatomy bearinguponthe definition
anduseofbiodynamicscoordinatesystems. Moreover,thesame principlesapplywhendefininganatomical coordinatesystems
for children, and for non-human mammalian species used in ethical biodynamics research, development, testing and
evaluation.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
InternationalStandard. Atthe time of publication,the editionsindicatedwere valid. Allstandards are subjectedto
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibilityofapplyingthe mostrecenteditionsofthe standardsindicatedbelow. MeFnbersof IEC and ISO maintain
registersofcurrentlyvalidInternationalStandards.
ISO 1503:1977, Geometrical orientationanddirectionsofmovements.
1S0 5805:1997, Mechanical vibrationand shock— Human exposure— Vocabulary.
IS 14910:2001
ISO 8727:1997
3 Biodynamlc coordhtate systems
Standard biodynamicscmrdinate systemsshallbeused,ifpracticable,whenever collecting,transforming,analysing,
reporting,describing,comparing, or evaluating human mechanical vibrationand shock input data and consequent
human body structural and system responses.
NOTES
1 Abiodynarniccoordinatesystemmaybe orientedwithrespecttoahierarchyofcoordinatesystemswithininertialspace (see
figuresA.1 and A.2). Such inertial reference systems may be geocentric, in which the principalor normal axis lies in the
directionofearth’sgravity,orbasicentric,originatinginthecontactingswface (orsomefullyorientatable structureconnected
rigidlythereto)throughwNch theforceormotionofinterestistransmittedtothebody.Baaicentrfccoordinatesystemsmay,for
example, bedefinedwithrespecttothestructureofavehicle,aworkplace,oralaboratory,toanimmediatesourceofvibration
orshockaffectingpersons,suchasavibratingtoolorappliance,ortoaresearchvibrationmachine,motionsimulatororimpact
device. For research and evaluation purposes, a biodynamicscoordinate system may itself provide the external frame of
reference for an instrumentationcoordinate system, used to define inertial measurements made upon or withinthe human
body.
2 Geometricallyspeaking,thehumanbodymay,foranygivenposture,betreatedasafully-orientedobject(see figureA.3).
3 The use of coordhate systems originatingin amorphousor flexible soft-tissueor surface anatomical features which are
deformable orfreely mobilewithinthe body (e.g. coordinatesystems Ioosefydefined as centred inthe heart orthe buttocks)
precludes the precise acquisitionorcompatfsonofbiodynamicsdata, and isaccordinglydeprecated. The anatomical systems
defined in this International Standard all originate in, and are oriented with respect to, radiographically or stereotactically
determinable (includingpalpable) bony landmarks. Moreover, these systems are adaptable, forthe purpose of comparative
biodynamics, to mammalian species other than humans, and to mechanical analcgue models (dummies or manikins) of
humans.
4 A radiographicallydeterminable landmark means one that, for research or reference purposes,can be visualized, and its
positionmeasured, by methods of X-ray or ultrasonicradiographicalanthropcmetry. It may also be (but not necessarily is)
determinablestereotactically,ifitispalpable (orreliablyrelatedtostructuresthatare palpable) inthe surface anatomy. Itisof
courserecognizedthatinmanyareas andapplicationsitmaybeimpossibleorimpracticaltodefinethe relevantbonyanatomy
by radiographicalmethods. Nevertheless, the applicable anatomical coordinatesystem orsystems shouldbe identifiedwhen
inertialmeasurements are made on humans,andthe measurements relatedtothe standardanatomical coordinatesystem(s)
totheextentpracticable.
3.1 Direction

All orthogonal coordinate systems adopted in biodynamics shall be defined as right-handed (see figureA.4).

Definitionsof x-, y- and z-axes for anatomical coordinate systems shall be in accordance with ISO 5805 (see
figuresA.5 andA.6 forexamples ofthese axes). Definitionsoforientationsandaxes forbasicentricsystems(e.g. in
vehicles)shallbe inaccordancewiththe principlesofISO 1503.
NOTE— An exception to the rule regarding right-handedness of the coordinate system may be made in the case of the
anatomicalcoordinatesystem(hand)adoptedspecificallyformeasurementsinthelefthand(see 3.4.1).
3.2 Biodynamics coordinate systems for the whole body
3.2.1 Wholebody anatomical coordinate system
For most purposes (for example, when consideringforce or motion inputsto the whole body from a contact or
supportingsurface uponwhichthe personisstandhg, sittingor lying),the anatomicalcoordinatesystemofchoice
shallbethatdefinedforthepelvis(see 3.3.4).
NOTES
1 Whenpracticalconsiderationsclearfydictatethatitismore appropriateto do so, whole-body inputsmay be defined with
referencetoanalternativesystemwithinthetorso,which,togetherwiththepostureandtheorientationofthebodywithrespect
tothe source ofthe vibrationorshock, shouldbe defined unambiguouslywhen reportingdata referenced to this alternative
coordinate system. For example, whole-body inputsappfied mainly to a person’sback, as from a vibratingseat-back or a
motorizedbackpack appfiance, may be relatedtothe uppertorsoanatomicalcoordinatesystem. Unless otherwisespecified,
whole-bodyvibrationorshockshallbedeemed tobeappfiedtopereonsinthe(conventional)“normal”anatomicalposition,that
is,withthe z-axis ofthe principalaxial segmental (i.e. head andtrunk)anatomicalcoordinatesystemsapproximately parallel,
the limbsaligned, and the palms facing forward.When a particularposture is adopted (e.g. sitting)duringhuman vibration
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IS 14910:2001
ISO 8727:1997
measurements, asprwise anaKempt =~*ible $houldbe mtito~i~the relative odentatiM of~H~mdhate
systems relevant to the measurement. This may be done by quant~lng the extent of rotationof the principalaxes of each
segmental anatomical coordinate system (and, ifappropriate, displacement ofthe system’s origin)withrespect to itsnormal
anatomicalposition.
2 Bilateral (left-right) skeletal symmetry of the human body is an assumption implicit in the adoption of the anatomical
coordinatesystemsrecommended inthisInternationalStandard.
3.2.2 Basicentric coordinate systems for the whole body
3.2.2.1 Basicentric coordinate system for standing persons
Origin: The midpointofa lineinthe planeofacontactsurface(e.g. a ship’sdeckorthefloorofa vehiclecontaining
standingcrew or passengers) supportingthe standingperson, paesing beneath the lowermost pointsof the heel
bones(calcanei).
NOTE— The orientationofthislineintheplaneofthecontactsurfacecan bedefinedwithrespecttothecoplanar orientation
ofthatsurfaceasapracticalmatter,whenthereisahabitualstanceuponit(e.g.ofahumanoperatorataworkstation).
Orientation: The y-axis isthe linedefined above, withthe positivedirectionlyingto the sub~t’s left.The x-axis
passes throughthe origin,liesinthe plane ofthe contactsurface, and isperpendiculartothe y-axis. The z-axis is
mutuallyperpendiculartotheothertwoaxes (hence, normaltothecontactsurface).
NOTE— The orientations of a basicentric coordinate system with respect to the direction of gravity (or to a geocentric
coordinatesystem) varieswiththeorientationofavehicle andwiththe relativeorientationofavehcle andwiththeorientation
of supportingsurfaces withinthe vehicle. It may from time to time happen that the z-axes of the major anatomical (head,
pelvis),basicentricandgeocentriccoordinatesystemsareallapproximatelyaligned, aswhenapersonstandsonaship’sdeck
in a calm sea and gazes ahead at the horizon. However, non-alignment is more frequently the rule (for example, when a
personreclinesinacarseat whilethevehicleisclimbingahill,see 3.2.2.2).
3.2.2.2 Basicentric coordinate system for seated persons
Origin: The midpointof a line inthe plane of a contact surface (e.g. a vehicle seat) supportinga seated person,
passingthroughthe pressurearea ofthebuttocksandbeneaththe lowermostpointsoftheischialtuberoaities.
NOTE— The orientationofthislineintheplane ofthecontactsurfacecan be definedwithrespecttothecoplanarorientation

ofthatsurfaceasa practicalmatter,whenthere isa habitualsittingpositionandseat alignment(e.g. ofa humanoperatorata

workstation).
Orientation: Defined with respectto the originand the plane ofthe contact surface ina manner similarto that in
which a basicentric system for standing persons is defined above. The directionof the yaxie is positiveto the
subject’sleft.
NOTES
1 Ina normalsittingposture,the orientationofthe principalaxisofthebasicentriccoordinatesystemforpersonsseated ona
flatseat maybeassumed toapproximatetothatofthecorrespondingaxisoftheanatomicalcoordinatesystem(pelvis),
2 Forsome applications,a basicentricccmrdinatesystemforavehicledriver(ora mechanical humananaiogue) originatingat
the seat index point, SIP, (see ISO 5353) is used as a frame of reference, for example, in ergonomic or human factors
engineeringevaluationsoftractorseatsandthelike.Itsusepresupposesthattheseat ianormallypositionedandcentredinits
rangesofadjustmentwithrespecttothevehicleframe, andrelatesmeasurements tothegeometryofthevehicle. Reference to
the H-point (equivalent to the SIP for a normal adjustment of a tractor operator’s seat) is sometimes used for human
engineering purposes in the automotive industry.This practice, which has not been generally accepted int6rnational!y,is
generallynotusedinthecontextofbiodynamicalevaluationsofhumanexposuretovehiclevibrationandshockmotiin.
3 When whole-body vibration measurements are taken from a suitable formed instrumentation-mount interposed at the
intertace between a riderand hisaeat (see ISO 10326-1), the mountserves as the contact surface inti~ch the originand
orientation of the basicentric coordinate system for the seated pereon may be defined, that in turn provides the frame of
referencefortherelatedinstrumentationcoordinatesystem.
IS 1491 O:2OO1
ISO 8727:1997
4 When analysing,comparingand reportingbiodynamicaldata orinterpretinghumanvibrationand shockstandards applying
to seated subjects, due allowance should be made for any significant angle that may stand between the seat and the
geocentric(orvehicular)andinstrumentationcoordinatesystems.
3.3 Segmental anatomical coordinate systems
NOTE— An assumption impticitin the definitionand adoption of the followinganatomical coordinate systems is that the
respective body segment for which each system is established obeys to a sufficientapproximation the laws of rigid-body
mechanics. (This has been demonstratedforcertain biodynamicallyimportantskeletal segments, namely, the head and the
pelvis.)Forexamples, seefiguresA.1toA.6.
3.3.1 Anatomical coordinate system: head
Origin: The midpointofa lineconnectingthe superiormarginsofthe rightand leftexternal auditorymeatus ofthe
skull.
NOTE— Inclassicalanatomy,thatlineisthebaseofatriangledefiningthetransverseplaneofthehumanskull(theapex, i.e.
thethirdpointdefiningthatplane, isconventionallytheleftinfraorbitalnotch).
Orientation: The x-axis ofthissystempasses posteroanteriorlythroughthe originand liesinthe transverse plane
ofthe head. The y-axis passes throughthe origin,isdirectedpositivelyto the left, lies inthe same plane, and is
perpendiculartothex-axis.The z-axis ismutuallyperpendiculartotheothertwoaxes and isdirectedapproximately
throughthevertexoftheskull.
3.3.2 Anatomical coordinate system: root of neck
Origin: The anteriorsuperiorborderofthebodyofthefirstthoracicvertebra(TI )inthemidplaneofthatvertebra.
Orientation: The x-axis ofthissystem passes throughthe originand, posteroanteriorly,throughthe midpointof a
lineinthemidplaneofT1 connectingtheposterosuperiorandposteroinferiorpointsoftheposteriorspinousprocess
ofT1, The y-axis passes throughthe originand ismutuallyperpendiculartothe x- and z-axes. The z-axis passes
throughtheorigin,liesinthe midplaneofT1, andisperpendiculartothex-axis.
NOTE— The axesofthissystemarenotnecessarilyexactlyparallelwiththecorrespondingaxes ofthemajoraxialsegmental
anatomicalcoordinatesystems(head, pelvis)inthenormalanatomicalposition,andtherewillinanycase be divergenceswith
changesinposture.However,forthepurposesofdescribingforceandmotioninputstotheuppertorsoandthe rootoftheneck

in the normal anatomical position, a sufficient approximation may be presumed to exist between the orientation for the

midplane of T1 and the midsagittal plan e of the trunk. A precise descriptionof the postural relationships between body
segmentsisneededtodefinetheorientationofthesesystemsininertialspace.
3.3.3 Anatomical coordinate system: upper torso
Origin: The anteriorsuperiorborderofthefourththoracicvertebra(T4) inthe midsagittalplane.
Orientation: Defined inthecorrespondingmannerasforT1 above.
NOTE— Notein3.3.2 appliesequallytothissystem,
3.3.4 Anatomical coordinate system: pelvis
Origin: The midpointofa lineconnectingthe rightand leftanteriorsuperioriliacspines.That imaginarylineforms
the base ofan invertedtriangleconnectingthe anteriorsuperioriliacspineswiththe mostsuperioranteriorpointof
thesymphysispubis(whichaccordinglyformstheapexofthetriangle).
Orientation: The x-axis of this system projectsanteriorlyfrom the origin,it is perpendicularto the plane of the
triangle defined above. The y-axis is the line passing from rightto Ieff that connects the anterior superior iliac
spines.The z-axis ofthe system passes throughthe originand ismutuallyperpendiculartothe othertwo axes, it
liesintheplaneofthetriangleandbisectsit.

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IS 14910:2001
ISO 8727:1997
NOTES
1 The z-axisofthe anatomicalcoordinatesystem(pelvis)isapproximatelyverticalinhumansstandinguprightona horizontal
surfaceorsittingerectonahorizontalflatseat.
2 The pelvicanatomicalreferencepointsdefiningthebasictriangleusedtoestablishthiscoordinatesystem,althoughtheyare
normallypalpable inthe livinghumansubjectandinthecadaver(andareidentifiableradiographically)c,annotyetbedefined
withcompleteprecision,fortheyare irregularityroundedbonyprominences.They may indue coursebe superseded by more
exactlydeterminablepelvicreferencepointsifsuchcan beestablishedbyanatomists.Moreover, biodynamicalapplicationsof
\
thiscoordinatesystemassumeapproximatebilateralsymmetryofthepelvis.
3 Inbiodynamicalmeasurements inwhichthe motionofthepelvisisassumedtogenerate the mechanicalinputtothe lumbar
spine,itisnecessary inany finalanalysistodefine the locationand orientationofthe interfacebetween the sacrum andthe
bodyofthefifthlumbarvertebra(L5).
4 Althoughinrecliningand recumbentpostures,substantialfractionsofthe weightofthe personmay be distributedthrough
the upper body and the limbs, impressed vibrationor shock mayneverthelessbedeemedtoactthroughthepelvisorthe
body’sapproximatecentreof massfor the purposesof evaluatinghumanexposureto whole-bodyvibrationor shock.
Significanetxceptionstothisgeneralruleshouldbereported.
3.4 Biodynamics coordinate systems for the hand
3.4.1 Anatomical coordinate system: hand
Origin: The centreofthe headofthethirdmetacarpalbone(middleknuckle)ofeitherhand.
Orientation: This system isorientedtothe bonyanatomy ofthe hand bythe z-axis, the z-axis passes proximally
throughthe originand isthe longaxis of the third metacarpal bone. The x-axis of the system is approximately
normal to the palm of the hand, projectinganteriorly from the origin when the hand lies open in the normal
anatomicalposition,i.e.palmsfacingforward(see figureA.3). The y-axis passes throughthe origin,approximately
fromtherootofthefirsttothatofthelittlefinger,andismutuallyperpendiculartothex-andz-axes.
NOTES
1 Aspartof a right-handedorthogonalcoordinatesystem,they-axisoftheanatomicalcoordinatesystem(hand) isdefinedas
runningfromrighttoleft(i.e.fromthe rootofthe forefingertowardsthe rootofthe fittlefingerofthe righthand inthe normal
anatomicalposition).The mirrorimag e ofthissystem may be appliedspecificallytomeasurements inthe lefthand, butsuch

usage should be unambiguously identi fied when used as the basis for reporting hand-transmitted vibration data (see

ISO5349). Useofaleft-handedanatomicalcoordinatesystem,whilereasonableforapplicationtosymmetricalpartsontheleft
sideofthe body,can lead to anomalies invectoralgebra ifresultingdata are compared directfywiththose derived usinga
right-handedsystem(e.g. incorrectsignofvectorcross-products).
2 The absoluteorientationoftheanatomicalcoordinatesystem(hand)necessarilyvarieswiththe positionand postureofthe
hand,wristandupperlimb.Accordingly,itisrarelyparallelwiththecorrespondinglydesignatedcoordinatesystemsoftheaxial
bodysegments (head, thorax,pelvis).The postureofthe arm and hand shouldbe defined as preciselyas practicablewhen
referenceismade totheanatomicalcoordinatesystem(hand).The orientationofthesystem mayformanypracticalpurposes
beindependentlydefinedwithreferencetoanappropriatebasicentriccoordinatesystemoriginating,forexample, inavibrating
appliance, a workpiece, or a handle or control device held by the hand in question. Such a basicentric system may
‘simultaneouslyserve as theframeofreferencefortheinstrumentationcoor~nate systemwhen instrumentationisfixedtothe
objectgrasped,forthepurposeofmeasuringvibrationtransmittedtothesame hand.
3 When, as iscommonlydone inhandlingvibratingtoolsorhand-heldappliances, the hand isusedtograspa cylindricalor
approximatelycylindricalhandle,they-axisoftheanatomicalcoordinatesystem(hand) may notnecessarilybe assumedtolie
parallelwiththe axis ofthe handle, althoughsuchan assumptionmay be a sufficientapproximationforsome measurement
purposes.Itshouldbenotedthattheorientationoftheanatomicalcoordinatesystem(hand),beingdefinedbytheorientationof
the thirdmetacarpal bone, is, overa wide range of movement, essentially independent offlexionorextension ofthe fingers
(seefigureA.6).

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