/COM,ANSYS MEDIA REL. 2025R1 (11/08/2024) REF. VERIF. MANUAL: REL. 2025R1
/VERIFY,VM298
/TITLE,VM298,PSD ANALYSIS OF 40-STORY BUILDING UNDER WIND LOAD EXCITATION
/COM,
/COM, REFERENCE: J.N.YANG,Y.K.LIN,"ALONG-WIND MOTION OF MULTISTORY BUILDING"
/COM,            ASCE PUBLICATIONS, APRIL 1981.
/COM, 

/COM,
/COM, STRUCTURAL PARAMETERS OF BUILDING
_N      = 40                ! NUMBER OF STORIES
_H      = 4                 ! M, STORY HEIGHT
_HT     = _N*_H             ! M, TOTAL HEIGHT
_MASS   = 1.29E+6           ! KG, LUMPED MASS AT FLOOR LEVEL
_K      = 1E+9              ! N/M, ELASTIC STIFFNESS BETWEEN FLOORS
_BETA   = 2.155E+4          ! N/M/SEC, DAMPING COEFFICIENT BETWEEN FLOORS
/COM,
/COM, AERODYNAMIC PARAMETERS OF WIND EXCITATION
_Aw     = 192               ! M^2, WIND LOAD TRIBUTARY AREA
Zg      = 300               ! M, GRADIENT HEIGHT
_Ug     = 44.69             ! M/SEC, GRADIENT WIND VELOCITY
_Ur     = 11.46             ! M/SEC, REFERENCE MEAN WIND VELOCITY AT 10 M HEIGHT
_Cd     = 1.2               ! DRAG COEFFICIENT
_RHO    = 1.23              ! KG/M^3, AIR DENSITY
_KO     = 0.03              ! GROUND SURFACE DRAG COEFFICIENT
_ALPHA  = 0.4               ! EXPONENT FOR THE MEAN-WIND-PROFILE POWER LAW
_C1     = 7.7               ! CONSTANT TERM

_PI     = 4*ATAN(1)

/OUT,SCRATCH
/PREP7

/COM, NODES ALONG X
*DO,i,1,_N+1
    N,i,0,_H*(i-1),0        
*ENDDO

/COM, SPRING-DAMPER ELEMENTS
ET,1,14
KEYOPT,1,2,1
R,1,_K,_BETA
TYPE,1
REAL,1
MAT,1
*DO,i,1,_N
    E,i,i+1
*ENDDO

/COM, POINT MASS ELEMENTS
ET,2,21
KEYOPT,2,3,2
R,2,_MASS
TYPE,2
REAL,2
MAT,2
*GET,MAXNOD,NODE,0,NUM,MAX,,,
*DO,I,2,MAXNOD
    E,I
*ENDDO

/COM, NODE COMPONENTS
NSEL,S,LOC,Y,0
CM,NODE_BASE,NODE
NSEL,INVE
CM,NODE_FLOOR,NODE
ALLSEL,ALL,ALL

/COM, BOUNDARY CONDITIONS
CMSEL,S,NODE_BASE
D,ALL,ALL
ALLSEL,ALL,ALL
CMSEL,S,NODE_FLOOR
D,ALL,UY
D,ALL,UZ
ALLSEL,ALL,ALL
FINISH

/COM, ****************
/COM, MODAL ANALYSIS
/COM, ****************
NMODES = 1
/SOLU
ANTYPE,MODAL
MODOPT,LANB,NMODES
MXPAND
SOLVE
FINISH

*GET,FREQ_1,MODE,1,FREQ
OMG_1 = 2*_PI*FREQ_1

/COM, **************************
/COM, WIND LOAD SPECTRUM INPUT
/COM, **************************
FREQ_PTS = 120
FREQ_END = 2/(2*_PI)
FREQ_BEGIN = 1E-03          
FREQ_INC = (FREQ_END - FREQ_BEGIN)/FREQ_PTS

/COM, FREQUENCY TABLE (HZ)
*DIM,_FREQ_ARRAY,ARRAY,FREQ_PTS
*VFILL,_FREQ_ARRAY,RAMP,FREQ_BEGIN,FREQ_INC

/COM, CIRCULAR FREQUENCY TABLE (RAD/S)
*DIM,_OMG_ARRAY,ARRAY,FREQ_PTS
OMG_BEG = 2*_PI*FREQ_BEGIN
OMG_INC = 2*_PI*FREQ_INC
*VFILL,_OMG_ARRAY,RAMP,OMG_BEG,OMG_INC

/COM, TABLE OF DIRECT AND COSPECTRAL INPUT PSD WIND SPECTRUM VALUES (DAVENPORT)
*DIM,_COPHIFF,ARRAY,_N,_N,FREQ_PTS
*DO,j,1,_N
    _uj = _Ug*((j*_H)/Zg)**_ALPHA
    _vj = 0.5*_RHO*_Aw*_Cd*(_uj)**2
    *DO,k,j,_N
        _uk = _Ug*((k*_H)/Zg)**_ALPHA
        _vk = 0.5*_RHO*_Aw*_Cd*(_uk)**2
           COEFV = 4*_vj*_vk*2*_KO*_Ur**2
           COEFU = _uj*_uk
        *DO,i,1,FREQ_PTS
            OMG = _OMG_ARRAY(i)
            TERM1 = (600*OMG/(_PI*_Ur))**2
            TERM1 = TERM1/(1 + TERM1)**(4/3)
            EXPO  = -(_C1*OMG*ABS(j-k)*_H)/(2*_PI*_Ur)
            _COPHIFF(j,k,i) = COEFV*TERM1*EXP(EXPO)/(COEFU*OMG) 
        *ENDDO
    *ENDDO
*ENDDO

/COM, ***************
/COM, PSD ANALYSIS
/COM, ***************
/SOLU
ANTYPE,SPECTRUM                     ! PERFORM SPECTRUM ANALYSIS
SPOPT,PSD                           ! POWER SPECTRAL DENSITY ANALYSIS

_FACT = 4*_PI                       ! CONVERSION FACTOR FROM 2-SIDED INPUT PSD IN M2/RAD/S
                                    ! TO 1-SIDED INPUT PSD IN M2/HZ 
/COM, WIND SPECTRUM LOADING 
*DO,j,1,_N
    
    PSDUNIT,j,FORC
    *DO,k,j,_N
        *DO,i,1,FREQ_PTS
            PSDFRQ,j,k,_FREQ_ARRAY(i)
            *IF,j,EQ,k,THEN
               PSDVAL,j,_COPHIFF(j,j,i)*_FACT
            *ELSE 
               COVAL,j,k,_COPHIFF(j,k,i)*_FACT
            *ENDIF          
        *ENDDO  
    *ENDDO
    
    *IF,j,EQ,40,THEN
        /SHOW,PNG,REV
        /PLOPTS,DATE,0  
        PSDGRAPH,j-1,j,3            ! DISPLAY APPLIED WIND EXCITATION PSD SPECTRUM 
    *ENDIF
    
    *IF,j,EQ,1,THEN
        /SHOW,PNG,REV
        /PLOPTS,DATE,0  
        PSDGRAPH,j-1,j,3            ! DISPLAY APPLIED WIND EXCITATION PSD SPECTRUM
    *ENDIF
    
    FDEL,j,FX                       ! DELETE PREVIOUS WIND SPECTRUM LOAD    
    F,j+1,FX,1.0                    ! APPLY WIND LOAD ALONG X-DIRECTION     
    PFACT,j,NODE                    ! PERFORM THE PARTICIPATION FACTOR CALCULATION
*ENDDO  
/SHOW,CLOSE
    
FDEL,ALL,FX                         ! DELETE PREVIOUS NODAL WIND FORCE

PSDRES,DISP                         ! DISPLACEMENT RESPONSE (RELATIVE BY DEFAULT)
PSDCOM                              ! PSD MODE COMBINATION (USE DEFAULT TOLERANCE)
SOLVE
FINISH

/COM **********************************************************
/COM  POSTPROCESSING RESULTS AT TOP FLOOR
/COM **********************************************************
/POST1
SET,3,1
NSEL,,NODE,,41
/OUT,
/COM **********************************************************
/COM 1-SIGMA DISPLACEMENT SOLUTION FROM POST1
/COM **********************************************************
PRNSOL,U
/OUT,SCRATCH,,,APPEND
FINISH

/POST26
STORE,PSD,,,6.36E-03            ! USER-DEFINED FREQUENCY 6.36E-03 HZ (0.04 RAD/SEC)
NSOL,2,41,U,X                   ! STORE DISPLACEMENT UX OF 40TH FLOOR
RPSD,3,2,,1,2,RPSD_UX_HZ        ! CORRESPONDING RESPONSE PSD (ONE-SIDED M2/HZ)

! GET THE CIRCULAR FREQUENCY AS A VARIABLE (AS ON REFERENCE PLOT FIG.2)
VGET,FREQ,1
*VFACT,2*_PI
*VOPER,OMEGA,FREQ,MAX,FREQ
VPUT,OMEGA,4,,,OMEGA

! GET THE RPSD 2-SIDED IN M2/RAD/S (AS ON REFERENCE PLOT FIG.2)
VGET,RPSD_UX_HZ,3
*VFACT,(1/_FACT)
*VOPER,RPSD_UX,RPSD_UX_HZ,MAX,RPSD_UX_HZ
VPUT,RPSD_UX,5,,,RPSD_UX

/COM **********************************************************
/COM PLOT RPSD LIN-LOG (AS ON REFERENCE PLOT FIG.2)
/COM **********************************************************
/SHOW,PNG,REV
/AXLAB,X,FREQUENCY, [RAD/SEC]
/AXLAB,Y,RPSD OF TOP FLOOR,[M**2.SEC/RAD]
/YRANGE,1e-5,1e-1
/GROPT,LOGY,ON
XVAR,4
PLVAR,5

! PLOT RPSD LOG-LOG
/XRANGE,1E-2,2
/GROPT,LOGX,ON                          
PLVAR,5
/SHOW,CLOSE

/COM **********************************************************
/COM 1-SIGMA DISPLACEMENT SOLUTION FROM POST26
/COM **********************************************************
INT1,6,3,1                              ! RPSD INTEGRATION
*GET,D_VARIANCE,VARI,6,EXTREME,VLAST    ! VARIANCE
RMS_VALUE = SQRT(D_VARIANCE)            ! STANDARD DEVIATION
/COM **********************************************************
/COM REFERENCE STANDARD DEVIATION VALUE, SigmaX40 = 4.65E-2 M
/COM **********************************************************
*STATUS,RMS_VALUE
FINISH

*DIM,LABEL,CHAR,1,2
*DIM,VALUE,,2,3

LABEL(1,1)='RAD/SEC'
LABEL(1,2)='STD_DEV'

*VFILL,VALUE(1,1),DATA,1.02             ! MENTIONED IN THE REFERENCE PAPER
*VFILL,VALUE(1,2),DATA,OMG_1
*VFILL,VALUE(1,3),DATA,ABS(OMG_1/1.02)
*VFILL,VALUE(2,1),DATA,0.0465           ! MENTIONED IN THE REFERENCE PAPER
*VFILL,VALUE(2,2),DATA,RMS_VALUE
*VFILL,VALUE(2,3),DATA,ABS(RMS_VALUE/0.0465)

/OUT,vm298,vrt
/COM,
/COM, --------------- RESULT COMPARISON -------------------------------
/COM,
/COM,                 |  TARGET  |  MECHANICAL APDL  | RATIO     
/COM,
/COM,-------------------------------------------------------------------
/COM,  MODAL FREQUENCY
/COM,-------------------------------------------------------------------
/COM,
*VWRITE,LABEL(1,1),VALUE(1,1),VALUE(1,2),VALUE(1,3)
(1X,A12,'     ',F10.4,'  ',F14.4,'   ',F15.3)
/COM
/COM,-------------------------------------------------------------------
/COM,  STANDARD DEVIATION OF RESPONSE PSD
/COM,-------------------------------------------------------------------
/COM,
*VWRITE,LABEL(1,2),VALUE(2,1),VALUE(2,2),VALUE(2,3)
(1X,A12,'     ',F10.4,'  ',F14.4,'   ',F15.3)
/COM,
/COM,-------------------------------------------------------------------
/OUT,
*LIST,vm298,vrt
FINISH