fem modelling of a bellows and a bellows- based micromanipulator

VI. AnnexFEM modelling of a bellows and a bellows-based micromanipulator6.1.4 MICROMANIPULATOR MODELFINISH! Exits previous processor/CLE! Clears current database/PREP7! Enters the PREP7 pre-processorNLGEOM,ON! Large deflection onET,1,beam44! Defines a new elementR,1,18.8,5.11216E-4,5.11216E-4,.0381,.0381 ! Beam-element material propertiesMP,EX,1,161E6! Sets Young's Modulus to 1'160 [Pa]MP,DENS,1,8.85E-7 ! Sets the material density to 8,85·10 -7 [kg/mm 3 ]MP,NUXY,1,.3 ! Sets the Poisson's ratio to 0,3pi=acos(-1)! Defines the value of πR=9 ! Radius of the base "circle"L=18.796! Length of the bellowsplatform=10! Weight of the platform (if needed)alpha=8! Angle between one bellows' axis and the verticalalpharad=alpha*pi/180! Same angle in radianH=COS(alpharad)*L! Height of the actuation system (only the bellows part)TYPE,1 ! Sets the element types pointer to 1REAL,1 ! Sets the material real constant pointer to 1WPOF,-R! Offsets the working plane of the basis' radiusWPRO,-alpha! Rotates the workplane of -alpha degreesCSYS,4! Sets the active coordinate system to the workplaneN,1,! Creates the basis node of the first bellowsN, ,,L, ! Creates the free-end node of the first bellowsNSEL,s,,,1,2,1! Selects both last created nodesNROTAT,ALL! Rotates the nodal coordinate system to the active systemE,1,2! Defines a beam element between for the first bellowsCSYS,0! Sets the active coordinate system to the Cartesian oneWPRO,alpha! Re-rotates the working plane of alpha degreesWPOF,R! Re-offsets the working plane to its previous originWPSTYLE,,,,,,,,0! Controls the display and style of the working planeWPRO,,,120! Rotates the working plane of one 120º for the second bellowsWPOF,-R! Offsets the working plane of the basis' radiusWPRO,-alpha! Rotates the workplane of -alpha degreesCSYS,4! Sets the active coordinate system to the workplaneN,,! Creates the basis node of the second bellowsN, ,,L, ! Creates the free-end node of the second bellowsNSEL,S,,,3,4,1! Selects both last created nodesNROTAT,ALL! Rotates the nodal coordinate system to the active systemE,3,4! Defines a beam element between for the first bellowsWPRO,alpha! Re-rotates the working plane of alpha degreesWPOF,R! Re-offsets the working plane to its previous originWPRO,,,120! Rotates the working plane of one 120º for the second bellowsWPOF,-R! Offsets the working plane of the basis' radiusWPRO,-alpha! Rotates the workplane of -alpha degreesN,,! Creates the basis node of the second bellowsN, ,,L, ! Creates the free-end node of the second bellowsNSEL,S,,,5,6,1! Selects both last created nodesNROTAT,ALL! Rotates the nodal coordinate system to the active systemE,5,6! Defines a beam element between for the first bellowsWPRO,alpha! Re-rotates the working plane of alpha degreesWPOF,R! Re-offsets the working plane to its previous originWPRO,,,120! Rotates the working plane of one 120º for the second bellowsCSYS,0! Sets the active coordinate system to the Cartesian oneN,,,H! Creates the platform's middle nodeET,2,mass21! Defines element type nº 2 to be MASS21R,2,platform! Sets the mass of that element type to that of the platformTYPE,2 ! Sets the element types attribute pointer to 2REAL,2 ! Sets the element real constant attribute pointer to 2E,7,2 ! Defines mass element by node nº7NSEL,S,LOC,Y,H! Selects all free-end nodes of the bellows (slaves)NSEL,A,,,7! Selects also the middle node of the platform (master)CERIG,7,ALL,UXYZ! Defines a rigid region by those selected nodesWPSTYLE,,,,,,,,0! Controls the display and style of the working planeNSEL,S,LOC,Y! Selects all basis nodes of the bellows'D,ALL,ALL! Fixes all those nodes' degrees of freedomNSEL,ALL! Selects all nodesSAVE,beams,db! Saves current database as 'beams.db'54