Do you have any examples showing how to connect two parts with MPC contact?
Yes, please see the ANSYS 8.1 example below. In this example, the gap size can be varied along with the contact (MPC vs. Lagrange) and analysis (modal vs. static) types. For too large of a gap, the MPC contact is not established ... Note: This input is attached to this record, as well ... = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = fini /clear nflag=1 ! NFLAG= 1=modal analysis, anything else=static analysis ntype=2 ! NTYPE= 1=force-based MPC, 2=rigid-based MPC, else=augmented Lagrange gap=0.01! gap (inches) between bars ... (logic might fail for poor gap size) /title, MPC Contact vs. Augmented Lagrange Contact /plopts,info,1 /view,,1,2,3 /pnum,type,1 /num,1 /prep7 et,1,SOLID185 ! lower order brick et,2,SOLID187 ! higher order tetrahedron r,1 mp,ex,1,30.0e6 ! Young's modulus, psi mp,nuxy,1,0.30 ! Poisson's ratio, unitless mp,dens,1,0.283/386.4 ! mass density, lbf-sec^2/in^4 tb,biso,1 ! bilinear isotropic plasticity tbdata,1,60.0e3 ! yield stress, psi tbdata,2,30.0e4 ! tangent modulus, psi et,3,TARGE170 ! targets on lower order SOLID185 elements r,3mp,mu,3,0.0 et,4,CONTA174 ! contacts on higher order SOLID187 elements keyopt,4,9,1 ! exclude initial penetration or gap and offset ... keyopt,4,12,5 ! bonded (always) contact ... *if,ntype,eq,1,then ! force-distributed surface constraint keyopt,4,4,1 ! nodal detection - normal from contact surface keyopt,4,2,2 ! MPC based approach *elseif,ntype,eq,2,then ! rigid constraint surface keyopt,4,4,2 ! nodal detection - normal from target surface keyopt,4,2,2 ! MPC based approach *elsekeyopt,4,4,0 ! Gauss point detection (default) keyopt,4,2,0 ! augmented Lagrange approach (default) *endif block,0,3.000,0,1,0,1 block,3+gap,6,0,1,0,1 mat,1 type,1 real,1 esize,0.25 vmesh,1 type,2 esize,0.40 vmesh,2 nsel,s,loc,x,2.9995,3.0+(0.5*gap) cm,ntarg,node mat,3 type,3 real,3 esurf nsel,s,loc,x,3.0+(0.5*gap),1.001*(3.0+gap) ! logic fails for unreasonable gaps cm,ncont,node type,4 esurf nsel,all eplot fini /solu outres,all,all nsel,s,loc,x,0 d,all,all,0.0 nsel,all *if,nflag,eq,1,then antype,modal modopt,lanb,6 mxpand,6 *else antype,static nlgeom,on time,1.0 nsubst,5,500,5 nsel,s,loc,x,6 d,all,ux,0.20 d,all,uy,0.0,,,,uz nsel,all *endif save solve celist,,,,inte ! undocumented command to list internal CE's save fini /post1 set,last /edge,,1 *if,nflag,eq,1,then set,list *do,i,1,6 set,1,i plnsol,u,sum,2 /wait,0.5 *enddo *else /dscale,,1 plnsol,eppl,eqv *endif /eof = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = For gap=0.10" ============= *** NOTE *** CP= 7.438 TIME= 16:17:38 Deformable-deformable contact pair identified by real constant set 3 and contact element type 4 has been set up. Contact algorithm: MPC based approach *** NOTE *** CP= 7.438 TIME= 16:17:38 Contact related post- process items (ETABLE, pressure ...) are not available. Contact detection at: nodal point (normal to target surface) MPC will be built internally to handle bonded contact. Average contact surface length 0.32091 Average contact pair depth 0.24288 Default pinball region factor PINB 0.25000 The resulting pinball region 0.60720E-01 Default target edge extension factor TOLS 10.000 Initial penetration/gap is excluded. Bonded contact (always) is defined. *** NOTE ***CP= 7.438 TIME= 16:17:38 Min. Initial gap 0.1 was detected between contact element 672 and target element 665. The gap is closed due to initial adjustment. *** WARNING *** CP= 7.438 TIME= 16:17:38 The closed gap/penetration may be too large. Increase pinball if it is a true closed gap/penetration. Decrease pinball if it is a false one. *** WARNING *** CP= 7.438 TIME= 16:17:38 The initial penetration/gap is relatively large. Using bonded/no separation option may cause an accuracy issue. You may use the CNCHECK,ADJUST command to move the contact nodes towards the target surface. **************************************** = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = For gap=0.01" ============= *** NOTE *** CP= 8.891 TIME= 16:20:36 Deformable-deformable contact pair identified by real constant set 3 and contact element type 4 has been set up. Contact algorithm: MPC based approach *** NOTE *** CP= 8.891 TIME= 16:20:36 Contact related post- process items (ETABLE, pressure ...) are not available. Contact detection at: nodal point (normal to target surface) MPC willbe built internally to handle bonded contact. Average contact surface length 0.31972 Average contact pair depth 0.24429 Default pinball region factor PINB 0.25000 The resulting pinball region 0.61072E-01 Default target edge extension factor TOLS 10.000 Initial penetration/gap is excluded. Bonded contact (always) is defined. *** NOTE *** CP= 8.891 TIME= 16:20:36 Min. Initial gap 1.E-02 was detected between contact element 688 and target element 682. The gap is closed due to initialadjustment. **************************************** = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = . |
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