Bolted connection joints - Pretension element
Bolted connection joints - Pretension element
(OP)
Hi,
In one of the analysis requirement represented bolted connections between joint members using Prets179 with contact.
Beam 188 elements used for bolt connection. Bolt preload applied as the first load step and axial load applied as second load step.
Bolt diameter =12 mm; Bolt pre-load =50000N, Youngs modulus =2E5 Mpa Length of bolt (approx) =8 mm
Deformation of bolt = FL/AE = 0.017 mm
After performing this analysis, how to extract the bolt extension in first and second step..
Elogesh
In one of the analysis requirement represented bolted connections between joint members using Prets179 with contact.
Beam 188 elements used for bolt connection. Bolt preload applied as the first load step and axial load applied as second load step.
Bolt diameter =12 mm; Bolt pre-load =50000N, Youngs modulus =2E5 Mpa Length of bolt (approx) =8 mm
Deformation of bolt = FL/AE = 0.017 mm
After performing this analysis, how to extract the bolt extension in first and second step..
Elogesh





RE: Bolted connection joints - Pretension element
Along with this posted an attachment of APDL code to study the bolt joint stiffness ratio for simple two plate model.
But the joint stiffness ratio is affected by contact interface stiffness (FKN, Normal penalty stiffness).
The output from this execution writes an output file "Bolt_force_EX1.txt". In this you can observed that contact peneration is high(low FKN), but the bolt loads are logical and increasing under pulling external loads. But when contact penetratons are zero(High FKN), the bolt loads are decreasing and against the logic. So to decide the FKN value for rationale joint stiffness ratio, thought of seeing the bolt extension under preload and external load.But for applying the preload , the bolt divide into two halves. So not sure about the options to extract bolt beam displacement. Whetever I extracted as bolt displacement didn't match with calculated ones(FL/AE , F-force L-length, A-Area E =modulus) for the preload. Kindly let me know, how to extract bolt extension displacment and joint compression displacement under preload conditions.
Look forward for the directions from Ansys experts....
Advanced Thanks....
Elogesh
Link: http://files.engineering.com/getfile.aspx?folder=c...
RE: Bolted connection joints - Pretension element
Pl. find the APDL code pasted below.
The query is how to extract bolt deformation in structural analysis of joint members with bolted connection, which includes pre-tension elements and contact.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!To calculate bolt joint stiffness ratio!!!!!!!
!!!Two plate model!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
*do,a,0.01,1,0.01
PARSAV,SCALAR,'Parameters','txt',' '
Finish
/clear,start
/PREP7
PARRES,NEW,'Parameters','txt',' '
Sq_pl_dim=50 ! square plate dimension
Load_Sq_pl_dim=40 ! Square plate dimension- for load application
Bolt_dia=12 ! Bolt diameter
Bolt_rad=Bolt_dia/2 ! bolt radius
Washer_rad=1.5*Bolt_rad ! Washer diameter
Bolt_preload=50000 ! Bolt preload
Ext_force1=20000 ! External force
Plate1_thk=4 ! Thickness of joint members
Youngs_mod=2E5
Bolt_calc_stress_preload=Bolt_preload/(3.1415*Bolt_rad*Bolt_rad)
! Bolt stress calculation corresponding to preload = F/A !!!!!
Bolt_deformation=((3.1415*Bolt_rad*Bolt_rad)*(Youngs_mod))/(2*Plate1_thk)
!!!!!!!!!!!!!!!Bolt deformation =FL/AE !!!!!!!!!!
!*
ET,1,SHELL63
!*
KEYOPT,1,1,0
KEYOPT,1,3,0
KEYOPT,1,8,0
KEYOPT,1,9,0
mp,ex,1,2e5 ! Young's modulus of the material in MPa
mp,nuxy,1,0.3 ! Poissons ratio
mp,dens,1,7.85e-9 ! Density in Ton/mm3
btol,0.1e-3
R,1,4 ! Thickness of plate
RECTNG,-Sq_pl_dim,Sq_pl_dim,-Sq_pl_dim,Sq_pl_dim,
CYL4,0,0,Bolt_rad
ASBA, 1, 2
nummrg,all
numcmp,all
CYL4, , ,Bolt_rad, ,Washer_rad
aptn,all
CYL4, , ,Washer_rad, ,4*Bolt_rad
aptn,all
CSWPLA,11,0,1,1,
wprota,,90
asbw,all
wprota,,,90
asbw,all
alls
WPCSYS,-1,0
RECTNG,-Load_Sq_pl_dim,Load_Sq_pl_dim,-Load_Sq_pl_dim,Load_Sq_pl_dim,
aptn,all
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
asel,r,loc,x,0,Bolt_rad-1
aplot
adele,all
alls
aplot
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
asel,r,loc,x,0,4*Bolt_rad
aplot
esize,2
Type,1
mat,1
ESYS, 0
SECNUM, 1
MSHkey,1
amesh,all
alls
asel,u,loc,x,0,4*Bolt_rad
MSHkey,0
amesh,all
alls
agen,2,all,,,,,Plate1_thk,,0
EPLOT
ET,2,BEAM188
!*
SECTYPE, 2, BEAM, CSOLID, , 0
SECOFFSET, CENT
SECDATA,Bolt_rad,0,0,0,0,0,0,0,0,0,0,0
WPCSYS,-1,0
CSYS,0
WPAVE,0,0,0
CSYS,100
n,100000,0
n,200000,0,0,Plate1_thk/2
n,300000,0,0,Plate1_thk
TYPE, 2
MAT, 1
REAL,
ESYS, 0
SECNUM, 2
!*
e,100000,200000
*GET,High_elem_num1,ELEM,,NUM,MAX, , , ,
e,200000,300000
*GET,High_elem_num2,ELEM,,NUM,MAX, , , ,
alls
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
asel,r,loc,x,0,Washer_rad
ALLSEL,BELOW,AREA
nsel,r,loc,z,0
nsel,a,node,,100000
nplot
cerig,100000,all,all
allsel
asel,r,loc,x,0,Washer_rad
ALLSEL,BELOW,AREA
nsel,r,loc,z,Plate1_thk
nsel,a,node,,300000
nplot
cerig,300000,all,all
allsel
nplot
CSYS,0
nsel,r,loc,x,Sq_pl_dim
nsel,a,loc,x,-Sq_pl_dim
nsel,a,loc,y,Sq_pl_dim
nsel,a,loc,y,-Sq_pl_dim
nsel,r,loc,z,0
d,all,all,0
alls
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
nsel,r,loc,x,Washer_rad+1,4*Bolt_rad
Nplot
csys,0
nsel,r,loc,z,0
cm,nset1,node
alls
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
nsel,r,loc,x,Washer_rad+1,4*Bolt_rad
Nplot
csys,0
nsel,r,loc,z,Plate1_thk
cm,nset2,node
alls
nsel,r,loc,z,Plate1_thk
ESLN,R
EPLOT
ensym,,,,all
alls
ESEL,R,ENAME,,188
!*
PSMESH,111,pre, ,all, , 0,Z, ,200000
et,3,179
/COM, CONTACT PAIR CREATION - START
CM,_NODECM,NODE
CM,_ELEMCM,ELEM
CM,_KPCM,KP
CM,_LINECM,LINE
CM,_AREACM,AREA
CM,_VOLUCM,VOLU
/GSAV,cwz,gsav,,temp
MAT,1
R,3
REAL,3
ET,4,170
ET,5,174
KEYOPT,5,9,0
KEYOPT,5,10,2
R,3,
RMORE,
RMORE,,0
RMORE,0
KEYOPT,5,12,5
! Generate the target surface
NSEL,S,,,NSET1
CM,_TARGET,NODE
TYPE,4
ESLN,S,0
ESURF
CMSEL,S,_ELEMCM
! Generate the contact surface
NSEL,S,,,NSET2
CM,_CONTACT,NODE
TYPE,5
ESLN,S,0
ESURF
*SET,_REALID,3
ALLSEL
ESEL,ALL
ESEL,S,TYPE,,4
ESEL,A,TYPE,,5
ESEL,R,REAL,,3
/PSYMB,ESYS,1
/PNUM,TYPE,1
/NUM,1
EPLOT
ESEL,ALL
ESEL,S,TYPE,,4
ESEL,A,TYPE,,5
ESEL,R,REAL,,3
CMSEL,A,_NODECM
CMDEL,_NODECM
CMSEL,A,_ELEMCM
CMDEL,_ELEMCM
CMSEL,S,_KPCM
CMDEL,_KPCM
CMSEL,S,_LINECM
CMDEL,_LINECM
CMSEL,S,_AREACM
CMDEL,_AREACM
CMSEL,S,_VOLUCM
CMDEL,_VOLUCM
/GRES,cwz,gsav
CMDEL,_TARGET
CMDEL,_CONTACT
/COM, CONTACT PAIR CREATION - END
/COM, CONTACT PAIR PROPERTIES - START
KEYOPT,5,11,1
KEYOPT,5,12,0
RMODIF,3,3,a ! Effect of Normal penalty stiffness assessed
KEYOPT,5,9,1
KEYOPT,5,5,3
!! KEYOPT,5,2,1 ! Penalty method
KEYOPT,5,2,0 ! Augumented lagrange method
/COM, CONTACT PAIR PROPERTIES - END
/MREP,EPLOT
alls
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
/REPLOT
WPCSYS,-1,0
CSWPLA,100,1,1,1,
CSYS,100,
nsel,u,loc,x,Bolt_rad,Washer_rad+1
nsel,r,loc,x,Washer_rad+1,4*Bolt_rad
nplot
csys,0
!! nsel,r,loc,x,-Load_Sq_pl_dim,Load_Sq_pl_dim
nplot
!! nsel,r,loc,y,-Load_Sq_pl_dim,Load_Sq_pl_dim
nsel,r,loc,z,Plate1_thk
n,800000,0,0,Plate1_thk+0.1
Et,1000,21
R,1000,1e-3
Type,1000
Real,1000
E,800000
Cerigid,800000,all,all
nplot
cm,Ext_nodes,nodes
alls
finish
/solu
! New Pretension Section Load :: All Pret Sectns
SLOAD,ALL,9,LOCK,FORC,Bolt_preload, 1,2
alls
NSUBST,10,100,5
OUTRES,ERASE
OUTRES,ALL,ALL
TIME,1
lswrite,1
alls
/PSF,DEFA, ,2,0,1
/replo
f,800000,fz,Ext_force1
alls
NSUBST,10,100,5
OUTRES,ERASE
OUTRES,ALL,ALL
TIME,2
lswrite,2,
alls
alls
/solu
lssolve,1,2,1
finish
/post1
ESEL,R,ENAME,,188
SET,1,LAST,1,
ETABLE,Axi_for1,SMISC, 1,14
ETABLE,Dir_stress1,SMISC, 31,36
*GET,Force1_LS1,ELEM,High_elem_num1,ETAB,Axi_for1
*GET,Stress1_LS1,ELEM,High_elem_num1,ETAB,Dir_stress1
*GET,Force2_LS1,ELEM,High_elem_num2,ETAB,Axi_for1
*GET,Stress2_LS1,ELEM,High_elem_num2,ETAB,Dir_stress1
alls
ESEL,R,ENAME,,174
ETABLE,Cont_pene,NMISC, 9,10,11,12
*GET,Cont_pene_LS1,ELEM,6174,ETAB,Cont_pene
alls
SET,2,LAST,1,
ETABLE,Axi_for2,SMISC, 1,14
ETABLE,Dir_stress1,SMISC, 31,36
*GET,Force1_LS2,ELEM,High_elem_num1,ETAB,Axi_for2
*GET,Stress1_LS2,ELEM,High_elem_num1,ETAB,Dir_stress1
*GET,Force2_LS2,ELEM,High_elem_num2,ETAB,Axi_for2
*GET,Stress2_LS2,ELEM,High_elem_num2,ETAB,Dir_stress1
alls
ESEL,R,ENAME,,174
ETABLE,Cont_pene,NMISC, 9,10,11,12
*GET,Cont_pene_LS2,ELEM,6174,ETAB,Cont_pene
alls
Diff_Bolt21=Force1_LS2-Force1_LS1
alls
ESEL,S,ENAME,,174
ALLSEL,BELOW,ELEM
fsum,,both
SET,1,LAST,1,
fsum,,both
*GET,FSum_Z1,FSUM,,ITEM,FZ
SET,2,LAST,1,
fsum,,both
*GET,FSum_Z2,FSUM,,ITEM,FZ
Diff_joint21=FSum_Z1-FSum_Z2
joint_stifness_ratio1=Diff_Bolt21/Ext_force1
Diff1=Ext_force1-Diff_Bolt21-Diff_joint21
*do,i,1,2,1
SET,%i%,LAST,1,
/EFACET,1
PLNSOL, CONT,PRES, 0,1.0
*enddo
/EFACET,1
PLNSOL, CONT,PENE, 0,1.0
!!!Bolt_pre -Bolt preload !!!
!!!Joint_pre - Load at the joint interface corresponding to preload!!!!!
!!!External load - Applied external load!!!!!
!!!Bolt_Ext_load - Cumulative bolt load includes preload
!!Bolt_share_Ext - Share of external load taken by bolt
!!Joint_share_Ext - Share of external load taken by joint
!!JS_ratio - Joint stiffness ratio
!!Bolt_str_pre - Bolt stress preload
!!Bolt_str_Ext - Bolt stress external load
!!Cont_pene_LS2 - Contact penetration under external load
*CFOPEN,'Bolt_force_EX','txt',' ',APPEND
*VWRITE,'Bolt_Pre:','Joint_pre','Ext_load:','Bolt_Ext_load:','Bolt_share_Ext:','Joint_share_Ext:','JS_ratio','Bolt_str_pre','Bolt_str_Ext','Cont_pene_LS2'
(1X,A11,1X,A11,1X,A11,1X,A11,1X,A11,1X,A11,1X,A11,1X,A11,1X,A11,1X,A11)
*VWRITE,Force1_LS1,FSum_Z1,Ext_force1,Force1_LS2,Diff_Bolt21,Diff_joint21,joint_stifness_ratio1,Stress1_LS1,Stress1_LS2,Cont_pene_LS2
(F12.1,F12.1,F12.1,F12.1,F12.1,F12.1,F12.1,F12.1,F12.1,F12.1)
*CFCLOS
finish
*enddo
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!????How to extract bolt deformation under preload as well as external load!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!