Following answers

Hi

As I Know the development of XFEM (Extended Finite Element Method) to FEM is that in XFEM, you don't need to Re-Meshing for calculate data for growth of crack in your model and reducing the calculation procedure. But I think you don't use best Elements configuration to make your FEM model.

Are you sure that you check convergence and confirm your FEM model?

Try to compare with an experimental results to know which results (FEM or XFEM) is more accurate.

Thanks you all for your valuable reply. I am using PLANE 182 for both FEM and XFEM. Can you try it by ABAQUS if you have...And check the error...Experimental is good to check...but it will take some time....In experiment thickness should be defined...but i am taking 2d...what will be the effect of thickness of sample on SIF K1......

Please try this code.... XFEM will run in ANSYS 17..... There was some mistake in selection of crack tip node in previous code of FEA (SIF 1002). but after correction i am getting very high sif (19652) compare to analytical and XFEM. Try theoretical also (Fracture Mechanics by Prashant Kumar, IIT KANPUR). !//**************************** FEM Code (In this)******************************************** /NOPR   ! Suppress printing of UNDO process /PMACRO ! Echo following commands to log    FINISH  ! Make sure we are at BEGIN level   /CLEAR,NOSTART  ! Clear model since no SAVE found   ! WE SUGGEST YOU REMOVE THIS LINE AND THE FOLLOWING STARTUP LINES   !*  *SET,PI,ACOS(-1) /DIST,1,1.08222638492,1 /REP,FAST   !*  *SET,a,5 *SET,l,20   *SET,w,10   /prep7     ! Enter preprocessor !   !*  ET,1,PLANE182   !*  KEYOPT,1,1,0 KEYOPT,1,3,2 KEYOPT,1,6,0 KEYOPT,1,10,0   !*  !*  !*  MPTEMP,,,,,,,,  MPTEMP,1,0  MPDATA,EX,1,,3e4 MPDATA,PRXY,1,,0.3  /REPLOT,RESIZE  !*  MPTEMP,,,,,,,,  MPTEMP,1,0  MPDATA,DENS,1,,1 !*  K,1,0,a/400,,   K,2,(3*a/4),(a/400),, K,3,a,,,   K,4,(3*a/4),(-a/400),, K,5,0,(-a/400),, K,6,0,-l/2,, K,7,w,-l/2,, K,8,w,0,,   K,9,w,l/2,, K,10,0,l/2,, /REPLOT,RESIZE  /REPLOT,RESIZE  L,       1,       2 L,       2,       3 L,       3,       4 L,       4,       5 L,       5,       6 L,       6,       7 L,       7,       8 L,       8,       9 L,       9,       10 L,       10,       1 /REPLOT,RESIZE  FLST,2,10,4 FITEM,2,5   FITEM,2,4   FITEM,2,3   FITEM,2,2   FITEM,2,1   FITEM,2,10  FITEM,2,9   FITEM,2,8   FITEM,2,7   FITEM,2,6   AL,P51X !*  /AUTO,1 /REP,FAST   GPLOT   FLST,5,4,4,ORDE,4   FITEM,5,5   FITEM,5,7   FITEM,5,-8  FITEM,5,10  CM,_Y,LINE  LSEL, , , ,P51X CM,_Y1,LINE CMSEL,,_Y   !*  LESIZE,_Y1, , ,10, , , , ,1 !*  FLST,5,2,4,ORDE,2   FITEM,5,6   FITEM,5,9   CM,_Y,LINE  LSEL, , , ,P51X CM,_Y1,LINE CMSEL,,_Y   !*  LESIZE,_Y1, , ,20, , , , ,1 !*  !KSCON,3,a/16,1,16,0.5, !*  KSCON,3,0.3125,1,16,0.5, !*  MSHAPE,0,2D MSHKEY,0 !*  CM,_Y,AREA  ASEL, , , ,       1 CM,_Y1,AREA CHKMSH,'AREA'   CMSEL,S,_Y  !*  AMESH,_Y1   !*  CMDELE,_Y   CMDELE,_Y1  CMDELE,_Y2  !*  klist,all,,,coord   EPLOT   FLST,5,2,4,ORDE,2   FITEM,5,7   FITEM,5,-8  CM,_Y,LINE  LSEL, , , ,P51X CM,_Y1,LINE CMSEL,,_Y   !*  LESIZE,_Y1, , ,80, , , , ,1 !*  CM,_Y,AREA  ASEL, , , ,       1 CM,_Y1,AREA CHKMSH,'AREA'   CMSEL,S,_Y  !*  !*  ACLEAR,_Y1  AMESH,_Y1   !*  CMDELE,_Y   CMDELE,_Y1  CMDELE,_Y2  !*  /DIST,1,1.08222638492,1 /REP,FAST   FLST,2,21,1,ORDE,3  FITEM,2,2   FITEM,2,12  FITEM,2,-31 !*  /GO D,P51X, , , , , ,ALL, , , , ,   FLST,2,21,1,ORDE,3  FITEM,2,112 FITEM,2,192 FITEM,2,-211 /GO !*  SF,P51X,PRES,-100   FINISH  /SOL /STATUS,SOLU SOLVE   /DIST,1,1.08222638492,1 /REP,FAST   FINISH  /PREP7  FINISH  /POST1  FLST,2,5,1  FITEM,2,212 FITEM,2,231 FITEM,2,227 FITEM,2,233 FITEM,2,1 !*  PATH,p1,5,30,20, PPATH,P51X,1 PATH,STAT   !*  /PBC,PATH,1 /REPLOT /PBC,PATH,0 !*  /REPLO  /FOC,   1,   4.43353274289    , -0.286633283438E-02,   0.00000000000 /REPLO  !*  CS,11,0,227,248,244,1,1, CSYS,11, !*  RSYS,11 AVPRIN,0 AVRES,2, /EFACET,1   LAYER,0 FORCE,TOTAL !*  /DIST,1,1.08222638492,1 /REP,FAST   KCALC,0,1,3,0   !//**************************** XFEM Code (In this)******************************************** /NOPR ! Suppress printing of UNDO process /PMACRO ! Echo following commands to log FINISH ! Make sure we are at BEGIN level /CLEAR,NOSTART ! Clear model since no SAVE found ! WE SUGGEST YOU REMOVE THIS LINE AND THE FOLLOWING STARTUP LINES ! WE SUGGEST YOU REMOVE THIS LINE AND THE FOLLOWING STARTUP LINES /prep7 ! used to create a cdb file if needed *SET,_geomgen,1 *SET,_exit,0 *if,_geomgen,eq,1,then *SET,a,5 !--- CRACK LENGTH *SET,W,10 !--- WIDTH OF MODEL *SET,H,20 !--- HEIGHT OF MODEL *SET,PRES,100 !--- PRESSURE *SET,E,3.0e4 !--- YOUNG'S MODULUS *SET,NU,0.3 !--- POISSON'S RATIO *SET,RO,1.0 !--- DENSITY ! element types etc et,1,182 keyopt,1,3,2 ! continuum material behavior mp, ex, 1, 3.e04 mp, nuxy, 1, 0.3 mp, dens, 1, 1. ! define keypoints k, 1, 0.0, -2.0 k, 2, W, -2.0 k, 3, W, 2.0 k, 4, 0.0, 2.0 k, 5, W, -H/2 k, 6, 0.0, -H/2 k, 7, 0.0, H/2 k, 8, W, H/2 ! define area with KP a, 1,2,3,4 a, 1,2,5,6 a, 3,4,7,8 ! set up the meshing size *SET,xnume,79 ! number of elements in x, which should be odd *SET,ynume,33 ! number of elements in y , which should be odd lsel,s,line,,1,3,2 LESIZE,all, , ,xnume, , , , ,1 lsel,s,line,,2,4,2 LESIZE,all, , ,ynume, , , , ,1 ! mesh the area type, 1 mat, 1 MSHKEY,1 amesh,1 esize,10/5 MSHKEY,0 amesh,2,3 allsel ! Element component required for XFENRICH command esel, s, cent, y, -2,2 esel, r, cent, x, 0,9 cm, testcmp, elem allsel ! ! define enrichment identification ! xfenrich, ENRICH1, testcmp, , SING,1.5 allsel *SET,yc , 0.0 *SET,xc , 5.0 nsel, s, loc, x, 0 , xc esln,s, esel, r, cent, y, -1e-3, 1e-3 cm, cenelem, elem *SET,nelem , 1000 *SET,iel , 0 *SET,Phi , 0.0 *SET,Psi , 0.0 *do, i, 1, nelem, 1 *SET,iel , elnext(iel) *if, iel, ne, 0, then *do, j, 1, 4, 1 *SET,nd , nelem(iel,j) *SET,Phi , ny(nd) - yc *SET,Psi , nx(nd) - xc xfdata, ENRICH1, LSM, iel, nd, Phi, Psi *enddo *endif *enddo xflist ! crk tip element esel,s,cent,x,xc-10/xnume/2,xc+10/xnume/2 esel,r,cent,y,-1e-2,1e-2 cm, crktipelem, elem allsel,all FLST,2,1,4,ORDE,1 FITEM,2,6 !* /GO DL,P51X, ,ALL, FLST,2,1,4,ORDE,1 FITEM,2,9 /GO !* SFL,P51X,PRES,-100, cdwrite,all,xfem-sl201s,cdb *if,_exit,eq,1,then ! /exit,nosave *endif *else cdread,db,xfem-sl201s,cdb *endif fini ! Solution Module /solu antype,0 time, 1.0 deltim, 0.1, 1.0E-01, 0.2 outres,all, all ! CINT calculations CINT, NEW, 1 CINT, TYPE, JINT CINT, CXFE, crktipelem CINT, NCON, 8 CINT, NORM, 0, 2 CINT, NEW, 2 CINT, TYPE, SIFS CINT, CXFE, crktipelem CINT, NCON, 8 CINT, NORM, 0, 2 solve fini /post1 set,last,last /OUT PRCINT,1,,JINT PRCINT,2,,K1 PRCINT,2,,K2 !* /EFACET,1 PLNSOL, S,EQV, 0,1.0 !**************** Analytical ******************** clc clear all % Calculation of SIF sigma=100; a=5; W=10 alpha=a/W; f=1.12-0.23*alpha+10.55*(alpha^2)-21.72*(alpha^3)+30.39*(alpha^4) sif_1=(sigma*(sqrt(pi*a)))*f