諧響應分析四案例!

諧響應分析


諧響應分析 用于確定線性結構在承受隨時間按正弦(簡諧)規律變化的載荷時的穩態響應,分析過程中只計算結構的穩態受迫振動,不考慮激振開始時的瞬態振動。

諧響應分析四案例!的圖1


本文主要分享四個諧響應分析案例,看似簡單,但只不過是模型簡單,麻雀雖小五臟俱全,通過這四個案例完全可以掌握諧響應分析方法,以進一步針對自己的模型需求進行諧響應分析。

一般諧響應分析前需要進行模態求解,案例一至四的模態求解都是采用了Block Lanczos方法求解模態(ANTYPE,mode,案例一至四的主要不同在于其諧響應分析(ANTYPE,HARMONIC)過程中。

案例一: 完全分析方法(HROPT,FULL)  ,施加位移激勵進行掃頻。
案例二:模態疊加法, 基于大質量法的加速度激勵進行掃頻 ,要知道,ANSYS軟件進行諧響應分析時只能施加位移載荷、節點力載荷,無法施加加速度載荷,而且施加非零位移時只能用完全求解器求解這樣不僅耗費計算資源,這里采用大質量法可以實現加速度載荷激勵形式。
案例三:與案例二的唯一區別是案例三的求解結果 在自然頻率區進行了密集計算 ,也就是說,在自然頻率處,掃頻步長更加密集。
案例四:本案例求解設置與案例二相同,其突出亮點是可以 自定義加速度載荷譜。 也就是說,可以定義在不同頻率施加不同的激勵,也可以理解為譜分析。


附件:命令流

1:

finish

/clear

/PREP7  

g=386.4            ! gravity in/sec^2

totg=1             ! load in g's

xa=g*totg          ! acceleration in/sec^2

pi=3.141592654     ! pi

/title,DIRECT DISPLACEMENT METHOD 

!!!!Pre-processing!!!!

RECTNG,20,,.25,, 

ET,1,PLANE42

UIMP,1,EX, , ,30e6, 

UIMP,1,NUXY, , ,.3, 

UIMP,1,DENS, , ,.000729,

LESIZE,2, , ,4, , , , ,1  

LESIZE,4, , ,4, , , , ,1  

LESIZE,1, , ,80, , , , ,1 

LESIZE,3, , ,80, , , , ,1 

MSHAPE,0,2D 

MSHKEY,1

AMESH,all   

nsel,s,loc,x,-10,.0001  

d,all,all,0

allsel,all

FINISH  

!!!!Solution Processing Modal Analysis!!!!

/SOLU   

ANTYPE,2

MODOPT,LANB,6   

EQSLV,SPAR  

MXPAND,6, , ,0  

MODOPT,LANB,6,0,0, ,OFF, ,0 

SOLVE   

FINISH  

!!!!Postprocess Modal Analysis!!!!

/POST1  

*GET,freq1,MODE,1,FREQ  

*GET,freq2,MODE,2,FREQ

*GET,freq3,MODE,3,FREQ

finish


!!!!Solution Process Full Harmonic Analysis!!!!

/solu

ANTYPE,3

HROPT,FULL  

HROUT,ON 

EQSLV,FRONT,0,     !波前求解器

DDELE,1,ALL  

nsel,s,loc,x,-10,.0001  

d,all,ux,0

d,all,uy,1

allsel,all

HARFRQ,freq2*.5,freq3*1.2, 

NSUBST,50, 

KBC,1     

DMPRAT,.0003,  

outres,all,all  

solve

finish


/POST26 

NSOL,2,83,U,Y,                     ! raw results

PROD,3,1,1, , , , ,2*pi,2*pi,1,    ! omega squared in radians

QUOT,4,2,3, , , , ,xa,1,           ! displacements: (raw results*accel)/omega^2

PROD,5,2, , , , , ,xa              ! accelerations: raw results*accel

PROD,6,2, , , , , ,xa/g            ! g's: (raw results*accel)/g

/eof

PLVAR,

案例2:

finish

/clear

/PREP7  

xm=1e5       ! mass for the large mass

g=386.4      ! acceration of gravity

totg=1       ! total number of g's applied to the model

xa=g*totg    ! acceleration applied to the model

xf=xm*xa     ! force required to applied desired acceleration f=ma

pi=3.141592654

/title,LARGE MASS METHOD ACCELERATION INPUT

RECTNG,20,,.25,, 

ET,1,PLANE42

UIMP,1,EX, , ,30e6, 

UIMP,1,NUXY, , ,.3, 

UIMP,1,DENS, , ,.000729,

LESIZE,2, , ,4, , , , ,1 

LESIZE,4, , ,4, , , , ,1  

LESIZE,1, , ,80, , , , ,1 

LESIZE,3, , ,80, , , , ,1 

MSHAPE,0,2D 

MSHKEY,1

AMESH,all   

numoff,node,100

!!!!Add large mass!!!

ET,2,MASS21 

KEYOPT,2,2,0

KEYOPT,2,3,0

R,2,1e5,1e5,1e5,1e5,1e5,1e5, 

n,1,-1   

type,2  

real,2  

mat,2   

e,1

nsel,s,loc,x,-1,0   

cerig,1,all,all,uxyz

allsel,all

numcmp,all 

FINISH  


!!!!MODAL ANALYSIS!!!!!!!!!!!!!!!!!!!!!!!

/SOLU   

ANTYPE,2

EQSLV,SPAR  

MXPAND,20, , ,0  

MODOPT,LANB,20,0,0, ,OFF, ,0   /! no shift get all rigid body modes

! this will allow the acceleration at the large mass to be calculated

! otherwise the acceleration at the large mass is incorrect

SOLVE   

FINISH  

!!!!HARMONIC ANALYSIS!!!!!!!!!!

/solu

ANTYPE,3

HROPT,MSUP,0, , 

HROUT,ON,OFF,0 

 EQSLV,FRONT,0,  

KBC,1   

DMPRAT,.03, 

outres,all,all  

f,1,fy,(xf)

harfrq,10,40

nsubst,25

solve

finish

!!!!POSTPROCESS TIME HISTORY!!!!!!!!!!!!!

/POST26 

file,,rfrq

NSOL,2,83,U,Y,                     !  node 83 displacement

PROD,4,1,1, , , , ,2*pi,2*pi,1,    ! omega squared

PROD,5,2,4, , , , ,1,1,1,          ! acceleration

PROD,6,5, , , , , ,1/g             ! results in g's

/AXLAB,X,Freqency   

/AXLAB,Y,Response in G  

/GROPT,LOGX,ON  

/GROPT,LOGY,OFF 

PLVAR,6

/eof

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Expansion results to .rst file!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

FINISH  

/SOLU   

EXPASS,1

NUMEXP,25,10,40,1  

HREXP,ALL,  

/STATUS,SOLU

SOLVE   

FINISH  

案例3:

finish

/clear

/PREP7  

xm=1e5       ! mass for the large mass

g=386.4      ! acceration of gravity

totg=1       ! total number of g's applied to the model

xa=g*totg    ! acceleration applied to the model

xf=xm*xa     ! force required to applied desired acceleration f=ma

pi=3.141592654

/title,LARGE MASS METHOD ACCELERATION INPUT

RECTNG,20,,.25,, 

ET,1,PLANE42

UIMP,1,EX, , ,30e6, 

UIMP,1,NUXY, , ,.3, 

UIMP,1,DENS, , ,.000729,

LESIZE,2, , ,4, , , , ,1 

LESIZE,4, , ,4, , , , ,1  

LESIZE,1, , ,80, , , , ,1 

LESIZE,3, , ,80, , , , ,1 

MSHAPE,0,2D 

MSHKEY,1

AMESH,all   

numoff,node,100

!!!!Add large mass!!!

ET,2,MASS21 

KEYOPT,2,2,0

KEYOPT,2,3,0

R,2,1e5,1e5,1e5,1e5,1e5,1e5, 

n,1,-1   

type,2  

real,2  

mat,2   

e,1

nsel,s,loc,x,-1,0   

cerig,1,all,all,uxyz

allsel,all

numcmp,all 

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

FINISH  

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!MODAL ANALYSIS!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

/SOLU   

ANTYPE,2

EQSLV,SPAR  

MXPAND,20, , ,0  

MODOPT,LANB,20,0,0, ,OFF, ,0   ! no shift get all rigid body modes

! this will allow the acceleration at the large mass to be calculated

! otherwise the acceleration at the large mass is incorrect

SOLVE   

FINISH  

/POST1  

finish

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!HARMONIC ANALYSIS!!!!!!!!!!!!!!!!!!!!!

/solu

ANTYPE,3

!*  

HROPT,MSUP,0, , 

HROUT,ON,OFF,0  EQSLV,FRONT,0,  

KBC,1   

DMPRAT,.03, 

outres,all,all  

f,1,fy,(xf)

harfrq,10,40

hrout,,on        ! turns cluster option on, ansys calculated freqs

nsubst,10        ! 1-10 default 4

solve

finish

!!!!POSTPROCESS TIME HISTORY!!!!!!!!!!!!!!!!!!!!!!

/POST26 

file,,rfrq

NSOL,2,83,U,Y,                     !  node 83 displacement

PROD,4,1,1, , , , ,2*pi,2*pi,1,    ! omega squared

PROD,5,2,4, , , , ,1,1,1,          ! acceleration

PROD,6,5, , , , , ,1/g             ! results in g's

/AXLAB,X,Freqency   

/AXLAB,Y,Response in G  

/GROPT,LOGX,ON  

/GROPT,LOGY,OFF 

PLVAR,6

/eof

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Expansion results to .rst file!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

FINISH  

/SOLU   

EXPASS,1

NUMEXP,25,10,40,1  

HREXP,ALL,  

!*  

/STATUS,SOLU

SOLVE   

FINISH  

案例4:

finish

/clear

/PREP7  

xm=1e5       ! mass for the large mass

g=386.4      ! acceration of gravity

totg=1       ! total number of g's applied to the model

xa=g*totg    ! acceleration applied to the model

xf=xm*xa     ! force required to applied desired acceleration f=ma

pi=3.141592654

/title,LARGE MASS METHOD ACCELERATION INPUT

RECTNG,20,,.25,, 

ET,1,PLANE42

UIMP,1,EX, , ,30e6, 

UIMP,1,NUXY, , ,.3, 

UIMP,1,DENS, , ,.000729,

LESIZE,2, , ,4, , , , ,1 

LESIZE,4, , ,4, , , , ,1  

LESIZE,1, , ,80, , , , ,1 

LESIZE,3, , ,80, , , , ,1 

MSHAPE,0,2D 

MSHKEY,1

AMESH,all   

numoff,node,100

!!!!Add large mass!!!

ET,2,MASS21 

KEYOPT,2,2,0

KEYOPT,2,3,0

R,2,1e5,1e5,1e5,1e5,1e5,1e5, 

n,1,-1   

type,2  

real,2  

mat,2   

e,1

nsel,s,loc,x,-1,0   

cerig,1,all,all,uxyz

allsel,all

numcmp,all 

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

FINISH  

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!MODAL ANALYSIS!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

/SOLU   

ANTYPE,2

EQSLV,SPAR  

MXPAND,6, , ,0  

MODOPT,LANB,6,1,0, ,OFF, ,0 

SOLVE   

FINISH  

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!HARMONIC ANALYSIS!!!!!!!!!!!!!!!!!!!!!

/solu

ANTYPE,3

HROPT,MSUP,0, , 

HROUT,ON,OFF,0  

EQSLV,FRONT,0,  

KBC,1   

DMPRAT,.03, 

outres,all,all  

!!!!FIRST SET OF FREQ AND LOAD!!!!

!!!!Parameters of sine sweep spec!!!!!!!!!!!!!!

bfreq1=5             ! begining freq

efreq1=50            ! endding freq

xload1=(.1*g)        ! acceleration of load

xoct1=.1             ! oct/time

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Determine how many frequency steps!!!!

cnt1=0

*do,i,1,50

  *if,i,ne,1,then

    dfreq=dfreq*(1+(xoct1*2))

  *endif

  *if,i,eq,1,then

    dfreq=bfreq1

  *endif

  

  *if,dfreq,lt,efreq1,then

    cnt1=cnt1+1

  *endif

*enddo

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!dimension freq table col1=freq col2=load!!!!

*dim,freq1,table,cnt1,2

*VFILL,freq1(0,0),RAMP,0,1,

*do,i,1,2

 *VFILL,freq1(0,i),RAMP,i,1,

*enddo

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Build freq table, load model, and solve!!!!!!

*do,i,1,cnt1

  *if,i,ne,1,then

    freq1(i,1)=freq1((i-1),1)*(1+(xoct1*2))

  *endif

  *if,i,eq,1,then

    freq1(i,1)=bfreq1

  *endif

  freq1(i,2)=xload1

  f,1,fy,(xm*xload1)

  

  harfrq,freq1(i,1),freq1(i,1)

  nsubst,1

  

  solve

*enddo

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!SECOND SET OF FREQ AND LOAD!!!!

!!!!Parameters of sine sweep spec!!!!!!!!!!!!!!

bfreq2=50             ! begining freq

efreq2=200             ! endding freq

xload2=(.5*g)          ! acceleration of load

xoct2=.1              ! oct/time

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Determine how many frequency steps!!!!

cnt2=1

*do,i,1,50

  *if,i,ne,1,then

    dfreq=dfreq*(1+(xoct2*2))

  *endif

  *if,i,eq,1,then

    dfreq=bfreq2

  *endif

  

  *if,dfreq,lt,efreq2,then

    cnt2=cnt2+1

  *endif

*enddo

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!dimension freq table col1=freq col2=load!!!!

*dim,freq2,table,cnt2,2

*VFILL,freq2(0,0),RAMP,0,1,

*do,i,1,2

 *VFILL,freq2(0,i),RAMP,i,1,

*enddo

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Build freq table, load model, and solve!!!!!!

*do,i,1,cnt2

  *if,i,ne,1,then

    freq2(i,1)=freq2((i-1),1)*(1+(xoct2*2))

  *endif

  *if,i,eq,1,then

    freq2(i,1)=bfreq2

  *endif

  freq2(i,2)=xload2

  f,1,fy,(xm*xload2)

  

  harfrq,freq2(i,1),freq2(i,1)

  nsubst,1

  

  solve

*enddo

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

finish

!!!!POSTPROCESS TIME HISTORY!!!!!!!!!!!!!!!!!!!!!!

/POST26 

file,,rfrq

NSOL,2,83,U,Y,                     ! displacement

PROD,4,1,1, , , , ,2*pi,2*pi,1,    ! omega squared

PROD,5,2,4, , , , ,1,1,1,          ! acceleration

PROD,6,5, , , , , ,1/g             ! results in g's

 /eof

/AXLAB,X,Freqency  

/AXLAB,Y,Response in G  

/GROPT,LOGX,ON  

/GROPT,LOGY,OFF 

PLVAR,6

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!Expansion results to .rst file!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

FINISH  

/SOLU  

EXPASS,1

*do,i,1,cnt1 

  EXPSOL,,,freq1(i,1) ,1  

  HREXP,ALL,  

  SOLVE 

*enddo  

!!!!!!!!!!!!!!!!!!

*do,i,1,cnt2

  EXPSOL,,,freq2(i,1) ,1  

  HREXP,ALL,  

  SOLVE  

*enddo

finish

全文結束,感謝閱讀。

諧響應分析四案例!的圖2

諧響應分析四案例!的圖3

諧響應分析四案例!的圖4

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