研讨会模态瞬态响应并加速nastran培训workshop07b.pptx

Workshop#7BModalTransientResponsewithEnforcedAcceleration

Workshop#7B-ModalTransientResponsewithEnforcedAccelerationUsingthemodalmethod,determinethetransientresponseduetoaunitaccelerationsinepulseof250Hzappliedatthebaseinthez-direction.Useastructuraldampingcoefficientofg=0.06andconvertthisdampingtoequivalentviscousdampingat250Hz.Besuretoincluderesidualvector.Belowisafiniteelementrepresentationoftheflatplate.Italsocontainstheloadsandboundaryconstraints.DrivePoint

Workshop7BUsesolutionfromworkshop7Aasastartingpointandmakeappropriatechanges.

SolutionForWorkshop#7B(cont.)IDSEMINAR,PROB7B

SOL112

TIME30

CEND

TITLE=TRANSIENTRESPONSEWITHBASEEXCITATION

SUBTITLE=USINGMODALTRANSIENTMETHOD,NOREDUCTION

ECHO=UNSORTED

SPC=200

METHOD=1000

SET111=23,33

DISPLACEMENT(SORT2)=111

VELOCITY(SORT2)=111

ACCELERATION(SORT2)=111

SUBCASE1

DLOAD=500TSTEP=100

$

OUTPUT(XYPLOT)

XGRID=YES

YGRID=YES

XTITLE=TIME(SEC)

YTITLE=BASEACCELERATION

XYPLOTACCELERATIONRESPONSE/23(T3)

YTITLE=BASEDISPLACEMENT

XYPLOTDISPRESPONSE/23(T3)

YTITLE=TIPCENTERDISPLACEMENTRESPONSE

XYPLOTDISPRESPONSE/33(T3)

$BEGINBULK

$

$PLATEMODELDESCRIBEDINNORMALMODES$EXAMPLE

$

INCLUDE’plate.bdf’

PARAM,COUPMASS,1

PARAM,WTMASS,0.00259

$

$SPECIFYSTRUCTURALDAMPING

$

PARAM,G,0.06

PARAM,W3,1571.

$

$APPLYEDGECONSTRAINTS

$

SPC1,200,12456,1,12,23,34,45

SolutionForWorkshop#7B(Cont.)EIGRL,1000,,,10

$

$APPLYACCELERATIONTOTHEBASE

$

SPC1,200,3,23

SPCD,600,23,3,1.0

TLOAD2,500,600,,ACCE,0.0,0.004,250.,-90.

$

$RBEMASSTOREMAININGBASEPOINTS

$

RBE2,101,23,3,1,12,34,45

$

$SPECIFYINTEGRATIONTIMESTEPS

$

TSTEP,100,200,2.0E-4,1

$

ENDDATA

SolutionForWorkshop#7B

PartialOutputFileForWorkshop#7B(Cont.)BaseAcceleration:GridPoint23

PartialOutputFileForWorkshop#7B(Cont.)BaseDisplacement:Gri