Do you have an example that shows exactly how NFORCE calculates
its values in a full harmonic response analysis?
Yes, please see the ANSYS 9.0 input below (which is also attached to this solution record as "nforce.inp"). This input consists of two blocks that are connected together by CP (coupled DOF) commands. One end is fixed and the other end of the cantilever has a tip load applied to it with both real and imaginary components. The element data is squared, then summed, then the square root is taken, and then the data from each each element is summed at a given node. The details are highlighted in the output results ... fini /clear /title, SRSS Test in Full Harmonic Response Analysis /plopts,info,1 /view,,1,2,3 /pnum,type,1 /num,1 /prep7 et,1,SOLID45 et,2,SOLID45 r,1 mp,ex,1,30.0e6 mp,nuxy,1,0.30 mp,dens,1,0.0007 block,0,5,0,1,0,1 block,5,10,0,1,0,1 esize,0.50 type,1 vmesh,1 n11=node(5.0,0.0,0.0) n12=node(5.0,0.0,0.5) n13=node(5.0,0.0,1.0) n14=node(5.0,0.5,0.0) n15=node(5.0,0.5,0.5) n16=node(5.0,0.5,1.0) n17=node(5.0,1.0,0.0) n18=node(5.0,1.0,0.5) n19=node(5.0,1.0,1.0) nsel,none type,2 vmesh,2 n21=node(5.0,0.0,0.0) n22=node(5.0,0.0,0.5) n23=node(5.0,0.0,1.0) n24=node(5.0,0.5,0.0) n25=node(5.0,0.5,0.5) n26=node(5.0,0.5,1.0) n27=node(5.0,1.0,0.0) n28=node(5.0,1.0,0.5) n29=node(5.0,1.0,1.0) nsel,all cp,,all,n11,n21 cp,,all,n12,n22 cp,,all,n13,n23 cp,,all,n14,n24 cp,,all,n15,n25 cp,,all,n16,n26 cp,,all,n17,n27 cp,,all,n18,n28 cp,,all,n19,n29 eplot fini /solu antype,modal modopt,lanb,10 ! block Lanczos modal analysis mxpand,10,,,yes nsel,s,loc,x,0.0 d,all,all,0.0 nsel,all solve save *get,freq1,mode,1,freq ! 1st frequency *get,freq2,mode,2,freq ! 2nd frequency *get,freq3,mode,3,freq ! 3rd frequency *get,freq4,mode,4,freq ! 4th frequency *get,freq5,mode,5,freq ! 5th frequency *get,freq6,mode,6,freq ! 6th frequency fini ! MODE FREQUENCY(HERTZ) ! ! 1 334.7519161629 ! 2 334.7519161638 ! 3 2027.060147620 ! 4 2027.060147620 ! 5 3210.528718405 ! 6 5201.027253448 ! 7 5417.594104150 ! 8 5417.594104150 ! 9 9651.400218760 ! 10 10029.39527864 /prep7 mp,dmpr,1,0.10 ! constant material damping coefficient fini /solu antype,harmic ! harmonic response analysis hropt,full ! full harmonic response hrout,off ! print results asamplitudes and phase angles outpr,basic,1 harfrq,0.99*freq4 ! close to 4th natural frequency kbc,1 ! step applied boundary conditions nsel,s,loc,x,10.0 nsel,r,loc,y,1.0 f,all,fy,1.0,0.5 ! real and imaginary tip load ... nsel,all solve save fini /post1 /graph,full force,total ! NFORC uses FORCE,TOTAL by default *status,n16 *status,n26 nsel,s,node,,n16 ! block 1 node with two elements summed nsel,a,node,,n26 ! corresponding block 2 node ... esln set,,, ,,, ,1 ! real data presol,f set,,, ,,, ,2 ! imaginary data presol,f hrcplx,,,360 ! amplitude values for omegat=360 presol,f nforce /eof = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ***** ANSYS RESULTS INTERPRETATION (POST1) ***** Use Full element graphics for all elements USE TOTAL FORCES FOR SOLUTION RESULTS NAME VALUE TYPE DIMENSIONS N16 46.0000000 SCALAR. NAME VALUE TYPE DIMENSIONS N26 156.000000 SCALAR = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = == = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = USE DATA SET 1 ON RESULT FILE FOR LOAD CASE 0 TIME/FREQUENCY= 2006.8 PRINT F ELEMENT SOLUTION PER ELEMENT ***** POST1 ELEMENT NODE TOTAL FORCE LISTING ***** LOAD STEP= 1 SUBSTEP= 1 FREQ= 2006.8 LOAD CASE= 0 THE FOLLOWING X,Y,Z FORCES ARE IN GLOBAL COORDINATES ELEM= 30 FX FY FZ 77 2.3575 0.15698 0.24832E01 68 2.6409 0.80705E010.72433E02 90 1.1190 0.10444 0.13653E02 99 1.3801 0.19393 0.74470E02 44 2.3530 0.17279 0.35565E01 35 2.6361 0.90853E01 0.22767E01 461.0987 0.11456 0.49823E02 => (FX_R1)**2= 1.2071417 66 1.3988 0.20969 0.16887E01 ELEM= 40 FX FY FZ 99 1.3801 0.19393 0.74470E02 90 1.1190 0.10444 0.13653E02 78 2.6409 0.80705E01 0.72433E02 88 2.3576 0.15698 0.24832E01 66 1.3988 0.20969 0.16887E01 46 1.0987 0.11456 0.49822E02 => (FX_R2)**2 = 1.2071417 45 2.6361 0.90853E010.22767E01 48 2.3530 0.17279 0.35565E01 ELEM= 61 FX FY FZ 166 2.6416 0.10545 0.18075E01 168 2.7989 0.28410E01 0.85658E04 190 1.2864 0.38538E01 0.67368E03 188 1.4337 0.12925 0.56061E02 133 2.6368 0.11566 0.22945E01 135 2.7941 0.32767E01 0179 4.5650 0.47156E01 0.17930E01 178 4.5789 0.42510E01 0.16974E01 156 2.2815 0.59681E010.11343E01 => (FX_I4)**2 = 5.2052423 157 2.2870 0.67503E010.12237E01 155 4.5561 0.53074E010.13897E01 146 4.5693 0.47764E010.11440E01 = = = = = == = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = HRCPLX MACRO FREQUENCY= NEAR 0.00 ANGLE= 360.000 PRINT F ELEMENT SOLUTION PER ELEMENT SRSS Test in Full Harmonic Response Ana FREQ=2006.789 AMPLITUDE ***** POST1 ELEMENT NODE TOTAL FORCE LISTING ***** CALCULATED LOAD CASE= 0 THE FOLLOWING X,Y,Z FORCES ARE IN GLOBAL COORDINATES ELEM= 30 FX FY FZ 77 4.9402 0.21806 0.40886E01 68 5.2877 0.23761 0.88031E02 90 2.3958 0.26368 0.31141E02. .99 2.7189 0.271710.12753E01 44 4.9295 0.24102 0.51969E01 35 5.2770 0.24905 0.26377E01 46 2.3701 0.27521 0.60630E02 => FX_A1 = (1.2071417 + 4.4053812)**0.5 66 2.7413 0.29471 0.27381E01 = (5.6125229)**0.5 = 2.3690764 ELEM= 40 FX FY FZ 99 2.7189 0.27171 0.12753E01 90 2.3958 0.26368 0.31141E02 78 5.2877 0.23761 0.88032E02 88 4.9402 0.21806 0.40886E01 66 2.7413 0.29471 0.27381E01 46 2.3701 0.27521 0.60629E02 => FX_A2 = (1.2071417 + 4.4053812)**0.5 45 5.2770 0.24905 0.26377E01 = (5.6125229)**0.5 = 2.3690764 48 4.9295 0.24102 0.51969E01 ELEM= 61 FX FY FZ 166 5.2865 0.13316 0.25274E01 168 5.3611 0.14057 0.18385E01 190 2.6280 0.15113 0.65027E02 188 2.6967 0.15585 0.83738E02 133 5.2758 0.14262 0.25719E01 135 5.3509 0.14494 0.17240E01 157 2.6214 0.15646 0.12272E01 156 2.7001 0.16624 0.16725E01=> FX_A3 = (2.0845584 + 5.2052423)**0.5.= (7.2898007)**0.5 = 2.6999631 ELEM= 71 FXFYFZ 188 2.6967 0.15585 0.83737E02 190 2.6280 0.15113 0.65028E02 179 5.3612 0.14058 0.18386E01 178 5.2865 0.13316 0.25273E01 156 2.7002 0.16624 0.16725E01 => FX_A3 = (2.0848472 + 5.2052423)**0.5 157 2.6214 0.15645 0.12272E01 = (7.2900895)**0.5 = 2.7000166 155 5.3510 0.14494 0.17240E01 146 5.2758 0.14262 0.25719E01 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ***** POST1 NODAL TOTAL FORCE SUMMATION ***** LOAD STEP= 9999 SUBSTEP= 0 THE FOLLOWING X,Y,Z FORCES ARE IN GLOBAL COORDINATES NODE FX FY FZ 46 4.740 0.5504 0.1213E01 => FX_ASUM = 2.3690764 + 2.3690764 = 4.7381528 156 5.400 0.3325 0.3345E01 => FX_ASUM = 2.6999631 + 2.7000166 = 5.3999797 ***** SUMMATION OF TOTALFORCES AND MOMENTS IN GLOBAL COORDINATES ***** FX = 10.14055 FY = 0.8828991 FZ = 0.4557521E01MX = 0.8601115 MY = 9.912676 MZ = 0.6557808 SUMMATION POINT= 0.0000 0.0000 0.0000 = = = = = = = = = = = = = = = = = = = = = = = = = = = = 

