13

()()( 10 )

()

13.1

13.1 d l F1 C E F2 f1

l710mm c165mm d0.254mm EX1.9E5 MpaPRXY0.3DENS7.92E-9Tn/mm3

F184N F21N 0 2000Hz 2000/8250Hz POST26

13.1

13.2

ANSYS6.1

13.2.1

CH13Harmonic Response of a Guitar StringStructural

1 Utility Menu | File | Change Jobname Change Jobname () 13.2 Enter new jobname ()CH13

13.2 2 Utility Menu | File | Change Title(Change Title) 13.3 Enter new title ()Harmonic Response of a Guitar String

13.3

3 Utility Menu | Plot | ReplotHarmonic Response of a Guitar String()

4Main Menu | Preference Preference of GUI Filtering () Structural()

13.2.2

ANSYS6.1 LINK1

1Main Menu | Preprocessor | Element Type | Add/Edit/Delete

Element Types ()() Library of Element Types () 13.4

13.4

2 13.4Structural Link2D Spar 1,, 2

(Library of Element Types) 3 Element Types ()Type 1 LINK1, 13.5 Element Types ()

13.5

13.2.3

EX DENS 2

1Main Menu | Preprocessor | Material Props | Material ModelsDefine Material Model Behavior () 13.6

13.6 2 Structural Linear Elastic Isotropic 1

EX PRXY 13.7

13.7 3 13.7 EX 1.9E5PRXY 0.3 1.9E5Mpa 0.3

4 13.6 Density Density for Material Number 1 (1) 13.8

13.8 1 5DENS 7.92E-9 1 7.92E-9Tn/mm3 1

6Define Material Model Behavior ()Material | Exit

7Main Menu | Preprocessor | Real Constants Real Constants () 13.9

13.9

8 Element Type for Real Constants () 13.10

13.10 13.11

9 13.10Type 1 LINK1 LINK1 Real Constant Set Number 1,for LINK1 ( LINK1) 13.11

10Cross-sectional area () 5.0671E-2

4

2d 5.0671E-2mm2 11 Real Constant Set Number 1,for LINK1

( LINK1) LINK1 12 Real Constants () Set 1

13.2.4

ANSYS6.1 ANSYS6.1

1Main Menu | Preprocessor | Modeling | Create | Nodes | In Active CS Create Nodes in Active Coordinate System ()13.12

13.12 2 Node number () 1 X,Y,Z 000

3 Node number () 31 X,Y,Z 71000 31

4 Utility Menu | PlotCtrls | Numbering Plot Numbering Controls () 13.13

13.13 5 Node numbers () ON131

6Main Menu | Preprocessor | Modeling | Create | Node | Fill between Nds ANSYS 1 31

1 31 Create Nodes Between 2 Nodes () 13.14

13.14 7ANSYS6.1131 Number of nodes to fill () 29 230 13.15

13.15

13.2.5

31 LINK1ANSYS

1Main Menu | Preprocessor | Modeling | Create | Elements | Auto Numbered | Thru Nodes ANSYS 1 2

2 ANSYS 1 2

3Main Menu | Preprocessor | Copy | Elements | Tuto Numbered Copy Elems Auto-Num ()

4 ANSYS Copy Elements (Automatically-Numbered) () 13.16

13.16

5 Total number of copies-including original () 30 Node number increment () 1ANSYS 30()

6 30 13.17

13.17 7 ANSYS Toolbar ()

13.3

()

13.3.1

84N 1 231 XY 31 X 84N

1Main Menu | Solution | Define Loads | Apply | Structural | Displacement |

On Nodes ANSYS 1 Apply U, ROT on Nodes () 13.18

13.18 2 DOFS to be constrained ()All

DOF Apply U, ROT on Nodes ()

3 Box 4 231 Apply U, ROT on Nodes ()( 13.18)

5DOFS to be constrained () YUYAll DOF 13.19

13.19

6Main Menu | Solution | Define Loads | Apply | Structural | Force/Moment | On Nodes 31

Apply F/M on Nodes (/)13.20

13.20 / 7 direction of force/moment (/)FX

8 real part of force/moment (/) 84 84N 13.21

13.21 9 ANSYS

13.3.2

1Main Menu Main Menu | Solution | New AnalysisNew Analysis () 13.22

13.22

2 New Analysis Static

3 Main Menu | Solution | Soln Controls Solution Controls () Advanced NL Advanced NL 13.23

4 5 Analysis Options

13.23 6.Main Menu | Solution | Analysis Options Static or Steady-State

Analysis () 13.24

13.24 7. Stress stiffness or prestress () Prestress ON

8

9Main Menu | Solution | Current LS/STATUS Command ()( 13.25) Solve Current Load Step ()(13.26)

10

13.25

13.26 11ANSYS

ANSYS( 13.27)

13.27

13.3.3

13.3.3.1

1Main Menu | Solution | Analysis Type | New AnalysisWarning ()( 13.28) New Analysis ()( 13.29)

13.28

13.29

2Warning () 3ModalModal ()

4Main Menu | Solution | Analysis Type | Analysis OptionsModal Analysis () 13.30

13.30 5Mode extraction method () Block Lanczos () No. of modes extract () 6

6 Incl prestress effects ()YES ANSYS

7 Block Lanczos Method () 13.31

13.31 8 6ANSYS6.1

13.3.3.2

230 Y

1Main Menu | Solution | Define Loads | Delete | Structural | Displacement |

On Nodes Delete Node Constraints () 2 Box ANSYS 230

3 Delete Node Constraints () 13.32

13.32 4 DOFs to be deleted ()UY ANSYS 230 Y

13.33

13.33

13.3.3.3

1Main Menu | Solution | Current LS/STATUS Command (

)( 13.34) Solve Current Load Step ()(13.35)

13.34

13.35 2 Solve

Current Load Step ()

3ANSYS ANSYS( 13.36)

13.36

13.3.4

8 31

13.3.4.1

1Main Menu | Solution | Analysis Type | New AnalysisWarning ()( 13.37) New Analysis ()( 13.38)

13.37

13.38

2Warning () 3 13.38 Harmonic Harmonic ()

4 Main Menu | Solution | Analysis Type | Analysis OptionsHarmonic Analysis () 13.39

13.39 5 Solution method ()Mode

Superposn DOF printout format ()Amplitud+phase

6 Mode Sup Harmonic Analysis () 13.40

13.40

7Mode Sup Harmonic Analysis ()Maximum mode number () 6

13.3.4.2 31

8 1N

1Main Menu | Solution | Define Loads | Delete | Structural | Force/Moment | On Nodes Delete Node Constraints ()

2 31 3 Delete F/M on NOdes () 13.41

13.41 4 Forme/moment to be deleted ()FX

5Main Menu | Solution | Define Loads | Apply | Structural | Force/Moment | On Nodes Apply F/M on NOdes ()

6 ANSYS6.1 8 Apply F/M on NOdes () 13.42

13.42 7 Direction of force/mom ()FY Real part of force/mom ()-1

8

13.43

13.43

13.3.4.3

1Main Menu | Solution | Load Step Opts | Time/Frequenc | Freq and Substps Harmonic Frequency and Substep Options () 13.44

13.44

2 Harmonic freq range () 02000 Number of substeps () 250 02000Hz 250

3 Stepped 4 5Main Menu | Solution | Load Step Opts | Output Ctrls | Solu Printout

Solution Printout Controls () 13.45

13.45 6None Print frequency ()

7Main Menu | Solution | Load Step Opts | Output Ctrls | DB/Results File Controls for Database and Results File Writing () 13.46

13.46 8Every substep

9

13.3.4.4

1Main Menu | Solution | Current LS/STATUS Command ()( 13.47) Solve Current Load Step ()(13.48)

13.47

13.48 2 Solve

Current Load Step ()

3ANSYS Solution is done! ()

4Main Menu | Finish Solution 5 ANSYS

13.4

(POST1)

(POST26)

13.4.1 POST1

(POST1)

1Main Menu | General Postproc | Results Summary 13.49 6

13.49

2 3Main Menu | General Postproc | Read Results | First Set ANSYS6.1 13.49

4Main Menu | General Postproc | Plot Results | Nodal SoluContour

Nodal Solution Data () 13.50

13.50

5 DOF solution ()Translation USUM ()

6Def+undeformaed Items to be plotted () 1

7 13.51

13.51

8Main Menu | General Postproc | Read Results | Next Set 4567 13.52 13.56 26

13.52

13.53

13.54

13.55

13.56

13.4.2 POST26

(POST26)

1Main Menu | TimeHist Postpro(POST26) Time History Variables () 13.57

13.57

2 Utility Menu | File | Open Results Select Results File ()CH13.rfrq

3 Select Database File ()CH13.db

13.58

TIMEFREQ ( 13.59)

13.58

4Calculator Calculator ()( ANSYS) 13.59

13.59

5 Add Time-History Variable

() 13.60

13.60 6 Nodal Solution | DOF Solution Y-Component of displacement

7 Variable Name ()UY_Node_16UY_Node_16 ( 13.61)

13.61

8

9 ANSYS 16()

UY_Node_16 2 13.62

13.62 10Amplitude Amplitude () X-Axis () FREQUY_Node_16

13 Utility Menu | PlotCtrls | Style | Graphs | Modify Axes Axes Modifications for Graph Plots () 13.63

13.72

12 Y-axis label (Y)AMPLAMPL

13

14 ANSYS

UY_Node_16( 16 Y)FREQ 13.64

13.64 16 13.73 8 322.3Hz970.5Hz 1629.4Hz POST1

POST26 GUI

Main Menu | TimeHist Postpro | Settings | File Main Menu | TimeHist Postpro | Define Variables Main Menu | TimeHist Postpro | Settings | Graph Main Menu | TimeHist Postpro | List Variables Main Menu | TimeHist Postpro | Graph Variables ANSYS6.1

ANSYS ANSYS Toobar ANSYS ANSYS6.1

13.5

ANSYS GUI(!)

!* /PREP7 /TITLE,HARMONIC RESPONSE OF A GUITAR STRING

/SHOW !* ET,1,LINK1 2 MP,EX,1,1.9E5 MP,PRXY,1,0.3 MP,DENS,1,7.92E-009 R,1,5.0671E-2, , N,1, N,31,710 FILL,1,31,29, , ,1,1,1, /PNUM,NODE,1 /REPLOT E,1,2 EGEN,30,1,1 /GO D,1, ALL D,2, UY, , , 31 F,31,FX,84 SAVE !* /SOLUTION ANTYPE,0 PSTRES,ON OUTPR,BASIC,1 SOLVE FINISH !* /SOLUTION ANTYPE,2 MODOPT,LANB,6 PSTRES,1 DDELE,2,UY,30 SOLVE FINISH !* /SOLUTION ANTYPE,3 HROPT,MSUP,6, , HROUT,OFF,OFF,0

FDELE,31,FX F,8,FY,-1, ! HARFRQ,0,2000, NSUBST,250, KBC,1 OUTPR,BASIC,NONE, OUTRES,ALL,ALL, SOLVE FINISH !* /POST1 SET,LIST SET,FIRST /EFACE,1 AVPRIN,0, , PLNSOL,U,SUM,1,1 FINISH !* /POST26 FILE,'CH13','rfrq','.' NUMVAR,200 PLCPLX,0 /AXLAB,Y,AMPL NSOL,2,16,U,Y, UY_NODE_16 PLVAR,2, FINISH