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本帖最后由 Chelsea 于 2011-3-16 02:03 编辑
转一个例子,应该很清楚了吧
Modal analyses are used to calculate the response of a mechanicalsystems subjected to a cyclic excitation. We will apply an AC voltageof 10V to calculate the forced harmonic response of the beam devicearound its resonance frequency.- /SOLU ! Enter solution processor
- ANTYP,HARM ! Harmonic analysis type
- HARFRQ,0.310E+06,0.314E+06 ! Frequency range for analysis
- NSUBST,10 ! Number of steps to calculate
- KBC,1 ! Step loads (no ramp)
- D,top_elec,VOLT,0.0 ! Assign zero potential to a node of top electrode
- D,bot_elec,VOLT,10.0 ! Assign cyclic potential of 10 V to top electrode
- NSEL,S,LOC,X,0 ! Select nodes at beam attachment point
- D,ALL,UX,,,,,UY,UZ ! Remove displacement DOFs from selected nodes
- NSEL,S,LOC,Y,0 ! Select nodes at beam centre line
- DSYM,SYMM,Y ! Define symmetry boundary conditions
- NSEL,ALL ! Select all nodes
- SOLVE ! Solve current load step
- FINISH ! Exit active processorReviewing results of harmonic analysisUse the input listing below to review the harmonic response of the piezo beam.
- /POST26 ! Enter time-history post-processor
- NSEL,S,LOC,Y,0 ! Select nodes with coordinates Y=0N
- SEL,R,LOC,Z,0 ! Reselect coordinates with Z=0N
- SEL,R,LOC,X,lbeam ! Reselect coordinates with X=lbeam
- *GET,ntip,NODE,,N, UM,MIN ! Get number of node at beam tip (selected node)
- NSOL,2,ntip,U,Z,tip_uz ! Store node ntip vert. displ. in variable tip_uz
- NSEL,ALL ! Select all nodes
- WPCSYS ! Align work-plane with global coordinate system
- PRVAR,2 ! List data for tip_uz variable
- PLVAR,2 ! Plot displacements as a function of frequency
- FINISH ! Exit active processor
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