/COM,ANSYS MEDIA REL. 2024R2 (05/10/2024) REF. VERIF. MANUAL: REL. 2024R2 /VERIFY,VM282 /TITLE,VM282,STEADY STATE VIBRATION ANALYSIS OF PISTON-FLUID SYSTEM /COM, -------------------------------------------------------------- /COM, REFERENCE: /COM, F. AXISA and J. ANTUNES, MODELLING OF MECHANICAL SYSTEMS: /COM, FLUID-STRUCTURE INTERACTION, VOLUME 3, 2007, PAGE:486. /COM, -------------------------------------------------------------- /OUT,SCRATCH ! *** FLUID COLUMN *** !--------------------- LF = 24 ! TUBE LENGTH RAD = 0.125 ! TUBE RADIUS RHOF = 1000 ! FLUID VELOCITY SONCF = 1000 ! SONIC VELOCITY (SPEED OF SOUND IN A FLUID) ! *** CALCULATED FLUID PARAMETERS *** !------------------------------------ PI = ACOS(-1) SF = PI*RAD**2 MF = RHOF*SF*LF KF = RHOF*SONCF**2*SF/LF ! *** PISTON (UNDAMPED -> MODAL DAMPING) *** !------------------------------------------- KS = KF ! SPRING STIFFNESS (GAMMA = KF/KS = 1) MS = MF/2 ! POINT MASS (MU = MF/MS = 2) F0 = 1000 ! APPLIED FORCE /PREP7 LOCAL,13,0,0,0,0, , , 90,1,1, WPCSYS,-1,13, CYl4,0,0,RAD, , , ,LF CSYS,0 N,1,-1,0,0 N,2,0,0,0 ET,1,COMBIN14 ! ELEMENT 1 - COMBIN14 KEYOPT,1,3,0 ! UX DEGREE OF FREEDOM R,1,KS ET,2,MASS21 ! ELEMENT 2 - MASS21 KEYOPT,2,3,2 ! 3D MASS WITHOUT ROTARY INERTIA R,2,MS ET,3,FLUID30,,0,,0 ! ELEMENT 3 - FLUID WITH UNSYM COUPLING R,3 MP,DENS,3,RHOF MP,SONC,3,SONCF ET,4,CONTA174 ! ELEMENT 4 - CONTACT ELEMENTS R,4 KEYOPT,4,2,2 ! MPC STYLE CONTACT KEYOPT,4,4,2 ! RIGID CERIG STYLE LOAD KEYOPT,4,12,5 ! BONDED CONTACT ET,5,TARGE170 ! ELEMENT 5 - PILOT NODE KEYOPT,5,2,1 ! DON'T FIX THE PILOT NODE KEYOPT,5,4,111111 TYPE,1 REAL,1 EN,1,1,2 TYPE,2 REAL,2 EN,2,2 TYPE,3 MAT,3 REAL,3 ESIZE,LF/200 VSWEEP,1 VSEL,S,,,1 NSEL,R,LOC,X,0 TYPE,4 REAL,4 ESURF TYPE,5 TSHAPE,PILO E,2 TSHAPE ALLSEL,ALL,ALL ESEL,S,ENAME,,30 NSEL,S,LOC,X,0 SF,ALL,FSI ALLSEL,ALL,ALL D,1,ALL D, 2, UY, , , , , UZ, ROTX, ROTY, ROTZ F,2,FX,F0 ALLSEL,ALL,ALL SAVE FINISH ! *** SOLUTION CONTROLS FOR MODAL ANALYSIS *** ! -------------------------------------------- /SOLUTION ANTYPE,MODAL MODOPT,UNSYM,10,,,,,BOTH MXPAND,ALL SOLVE *GET,FREQ_1,MODE,2,FREQ *GET,FREQ_2,MODE,3,FREQ *GET,FREQ_3,MODE,4,FREQ *GET,FREQ_4,MODE,5,FREQ *GET,FREQ_5,MODE,6,FREQ FINISH ! *** SOLUTION CONTROLS FOR MSUP HARMONIC ANALYSIS *** ! ---------------------------------------------------- /SOLUTION ANTYPE,HARM HROPT,MSUP HARFRQ,0.0,100.0 KBC,1 NSUB,1000 OUTRES,ERASE OUTRES,ALL,NONE OUTRES,NSOL,ALL ! *** MODAL DAMPING RATIOS *** ! ---------------------------- MDAMP,1,0.0,2.0453E-02,3.6948E-03,7.0040E-04,2.2468E-04,9.8247E-05 FDELE,ALL LVSCALE,1 SOLVE FINISH ! *** EXPANSION PASS *** ! ---------------------- /SOLUTION EXPASS,ON NUMEXP,ALL,,,NO SOLVE FINISH /POST1 FILE,vm282,rst SET,,,,3,1 *GET,RES_1,NODE,2,U,X *GET,PRES_1,NODE,1712,PRES SET,,,,3,9.9 *GET,RES_2,NODE,2,U,X *GET,PRES_2,NODE,1712,PRES FINISH ! *** TIME HISTORY POST PROCESSOR *** ! ----------------------------------- /POST26 /GROPT,LOGX,ON /GROPT,LOGY,ON NSOL,2,2,U,X /SHOW,PNG PLVAR,2 PRCPLX,1 PRVAR,2 EXTREME,2 NPRES = NODE(LF/2,0,0) NSOL,3,NPRES,PRES PLVAR,3 PRVAR,3 EXTREME,3 /SHOW,CLOSE FINISH /OUT, /COM, ----------------------------- /COM, FREQUENCY (Hz) VALUES /COM, ----------------------------- *STATUS,FREQ_1 *STATUS,FREQ_2 *STATUS,FREQ_3 *STATUS,FREQ_4 *STATUS,FREQ_5 /COM, ----------------------------- /COM, RESPONSE AMPLITUDE OF PISTON /COM, ----------------------------- *STATUS,RES_1 *STATUS,RES_2 /COM, ------------------------------------------ /COM, PRESSURE AMPLITUDE AT MID-COLUMN OF FLUID /COM, ------------------------------------------ *STATUS,PRES_1 *STATUS,PRES_2 /OUT,SCRATCH *DIM,LABEL,CHAR,5,3 *DIM,VALUE,,5,3 LABEL(1,1) = 'FREQ(f1), ','FREQ(f2) ','FREQ(f3) ','FREQ(f4) ','FREQ(f5) ' LABEL(1,2) = ' Hz',' Hz',' Hz',' Hz',' Hz' *VFILL,VALUE(1,1),DATA,9.916,24.583,43.729,63.895,84.395 *VFILL,VALUE(1,2),DATA,FREQ_1,FREQ_2,FREQ_3,FREQ_4,FREQ_5 *VFILL,VALUE(1,3),DATA,FREQ_1/9.9167,FREQ_2/24.5833,FREQ_3/43.7292,FREQ_4/63.8958,FREQ_5/84.3958 *DIM,LAB1,CHAR,2,2 *DIM,VALUE1,,2,3 LAB1(1,1) = 'RES_1, ','RES_f1 ' LAB1(1,2) = ' M',' M' *VFILL,VALUE1(1,1),DATA,2.47E-04,5.76E-03 *VFILL,VALUE1(1,2),DATA,RES_1,RES_2 *VFILL,VALUE1(1,3),DATA,ABS(RES_1)/2.47E-04,ABS(RES_2)/5.76E-03 *DIM,LAB2,CHAR,2,2 *DIM,VALUE2,,2,3 LAB2(1,1) = 'PRES_1, ','PRES_f1 ' LAB2(1,2) = ' MPa',' MPa' *VFILL,VALUE2(1,1),DATA,1.03E+04,2.64E+05 *VFILL,VALUE2(1,2),DATA,PRES_1,PRES_2 *VFILL,VALUE2(1,3),DATA,ABS(PRES_1)/1.03E+04,ABS(PRES_2)/2.64E+05 /COM, /OUT,vm282,vrt /COM,------------------- VM282 RESULTS COMPARISON -------------- /COM, /COM, | TARGET | Mechanical APDL | RATIO /COM, *VWRITE,LABEL(1,1),LABEL(1,2),VALUE(1,1),VALUE(1,2),VALUE(1,3) (1X,A8,A8,' ',F12.3,' ',F16.3,' ',1F15.3) /COM, /COM,RESPONSE AMPLITUDE OF PISTON /COM, *VWRITE,LAB1(1,1),LAB1(1,2),VALUE1(1,1),VALUE1(1,2),VALUE1(1,3) (1X,A8,A8,' ',F12.5,' ',F16.5,' ',1F15.3) /COM, /COM,PRESSURE AMPLITUDE AT MID-COLUMN /COM, *VWRITE,LAB2(1,1),LAB2(1,2),VALUE2(1,1),VALUE2(1,2),VALUE2(1,3) (1X,A8,A8,' ',F12.3,' ',F16.3,' ',1F15.3) /COM,---------------------------------------------------------- /OUT, FINISH *LIST,vm282,vrt FINISH