fem modelling of a bellows and a bellows- based micromanipulator

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FEM modelling of a bellows and a bellows-based micromanipulatorVI. Annex6.1.2 PRESSURE APPLIED INSIDE THE BELLOWSa) 2D-modelFINISH! Exits previous processor/CLE! Erases current databaseRESUME,meshed2d,db! Resumes database from 'meshed2d.db'pressure = 0.01 ! Sets the variable pressure to 0,01 [mN/mm 2 ]/TITLE, 2D-Bellows, under 0,01 [mN/mm^2] pressure ! Sets plot's title/SOLU! Enters SOLU processorKSEL,S,,,24,28,4! Selects some keypointsD,ALL, UY,,,,, ROTX,ROTY,ROTZ! Fixes some degrees of freedom for bottom nodes! The result is that these nodes can still move radiallyLSEL,S,,,1,4,3! Selects some nodesLSEL,A,,,6,7,1 ! " " "LSEL,A,,,15,22,7 ! " " "CM,intern,LINE! Creates component called 'intern', composed by lines,! and corresponding to the internal wall of the bellowsSFL,ALL,PRES,pressure, ,! Applies the pressure on those selected linesALLSEL,ALL! Selects allSOLVE! Runs the simulation/POST1! Enters the post-processor POST1/DSCALE,1,0! Imposes no scaling for the layoutPLNSOL,U,Y,2! Displays results by continuous lineFINISH! Exits postprocessingb) 3D Solid-modelFINISH! Exits previous processor/CLE! Erases the actual databaseRESUME,meshed3d,db,,! Resumes from databasePRESSURE=0.01 ! Sets pressure to 0,01 [N/mm 2 ]/PREP7! Enters pre-processorNSEL, S, LOC, Y, -r2! Selects bottom-nodesCLOCAL,11,1,0,0,0,0,-90! Creates a new coordinate-systemCSYS,11! New coordinate-system activeNROTAT,ALL! Rotates bottom-nodes' c.-s.D,ALL,UY! No movement allowed in angular directionD,ALL,UZ! No movement allowed in axial directionALLSEL,ALL! Selects all nodesCSYS,0! Cartesian coordinate system activated/SOLU! Enters Solution processorCMSEL,S,INTERN! Selecting intern surface of the bellows (areas only)NSLA,S,1! Selecting corresponding nodesSF,ALL,PRES,PRESSURE! Applies the internal pressureALLSEL,ALL! Selecting allSOLVE! Initiates solution calculationsFINISH! Exits postprocessingc) 3D Shelled-modelFINISH! Exits previous processor/CLE! Erases the actual databaseRESUME,shell43,db,,! Resumes from database/SOLU! Enters Solution processorPRESSURE=0,01 ! Sets pressure to 0,01 [N/mm 2 ]SFE, ALL, 2, PRES,,PRESSURE! Applies the internal pressure on face Nº2 of shell elementsNSEL, S, LOC, Y, -r2! Selects bottom nodesCLOCAL,11,1,0,0,0,0,-90! Defines new coordinate systemCSYS,11! New coordinate-system activeNROTAT,ALL! Rotates bottom-nodes' c.-s.D,ALL,UY! No movement allowed in angular directionD,ALL,UZ! No movement allowed in axial directionALLSEL,ALL! Selects all nodesCSYS,0! Cartesian coordinate system activatedSOLVE! Initiates solution calculationsFINISH! Exits postprocessing51
VI. AnnexFEM modelling of a bellows and a bellows-based micromanipulator6.1.3 APPLYING TIME-VARYING LOAD FOR THE SPRING-RATE Ka) 2D model with corresponding pressureFINISH! Exits previous processor/CLE! Clears current databaseRESUME,meshed2d,db! Resumes database 'meshed2d.db'/TITLE, Bellows under time-varying force ! Title for the layoutF=100 ! Maximum force F = 100 [mN]Tend=130! Time at the end of the simulationIncr=13! Number of time incrementsT1=Tend/Incr*3! Time at the second simulation stepS=(-(B/2)**2+(B/2+t)**2)*pi! Computation of the effective surface! on which the force F acts/PREP7! Enters the pre-processorCSYS,0! Cartesian coordinate system activatedNSEL, S, LOC, Y, -r2! Selects bottom nodesD,ALL, UY,,,,, ROTX,ROTY,ROTZ! No movement allowed in axial direction, and no rotationALLSEL,ALL! Selects all nodes/SOLU! Enters Solution processorNLGEOM,ON! Enables non-linear simulation*DIM,FORCE,TABLE,3,1! Defines array parameter FORCEFORCE(1,1)=0,F,-F ! Force values in column 1FORCE(1,0)=0,T1,Tend ! Corresponding time value in column 0FORCE(0,1)=1! Zeroth rowTM_START=1E-6 ! Starting time (must be > 0)TM_END=Tend! Ending time of the transientTM_INCR=Tend/Incr! Time increment*DO,TM,TM_START,TM_END,TM_INCR! Do for TM, from TM_START to TM_END in TM_INCR stepsTIME,TM! Time valueF=FORCE(TM)! Force value at time TMPressure=F/S! Computes the pressure induced by FNSEL, S, LOC, Y,t+2*r1+t+r2! Selects top nodesSF,ALL,PRES,Pressure! Applies the pressure to these nodesALLSEL,ALL! Selects allSOLVE! Initiates the simulation*ENDDO! End of the DO-loopSAVE,loads,db! Saves the database to 'loads.db'b) 2D model with solid regionFINISH! Exits previous processor/CLE! Clears current databaseRESUME,meshed2d,db! Resumes database 'meshed2d.db'/TITLE, Bellows under time-varying force ! Title for the layoutF=100 ! Maximum force F = 100 [mN]Tend=130! Time at the end of the simulationIncr=13! Number of time incrementsT1=Tend/Incr*3! Time at the second simulation stepS=(-(B/2)**2+(B/2+t)**2)*pi! Computation of the effective surface! on which the force F acts/PREP7! Enters the pre-processorCSYS,0! Cartesian coordinate system activatedNSEL, S, LOC, Y, -r2! Selects bottom nodesD,ALL, UY,,,,, ROTX,ROTY,ROTZ! No movement allowed in axial direction, and no rotationALLSEL,ALL! Selects all nodes/SOLU! Enters Solution processorNLGEOM,ON! Enables non-linear simulation*DIM,FORCE,TABLE,3,1! Defines array parameter FORCEFORCE(1,1)=0,F,-F ! Force values in column 1FORCE(1,0)=0,T1,Tend ! Corresponding time value in column 0FORCE(0,1)=1! Zeroth rowTM_START=1E-6 ! Starting time (must be > 0)TM_END=Tend! Ending time of the transientTM_INCR=Tend/Incr! Time increment*DO,TM,TM_START,TM_END,TM_INCR! Do for TM, from TM_START to TM_END in TM_INCR stepsTIME,TM! Time value52
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Helsinki University of Technology C
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PrefaceThe author wishes to thank t
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