This is a simple finite element model created to demonstrate the gasket material simulation. Two block elements with element type SOLID185 were generated as supporters and a gasket element INTER195 was created. The whole system is fixed along one side of each axes to prevent rigid body motion. A prescribed displacement is placed on top of the supporter element. The gasket material is assumed to have a nonlinear compression behavior with 5 different linear unloading slopes. A pressure stress cap of 1.0e-5 is imposed so that no tension stress is generated. Two load steps were used.
Following are the Mechanical APDL commands:
/prep7 !*+++++++++++++++++++++ !* Define Element Types !*+++++++++++++++++++++ et,1,185 et,2,195 !*++++++++++++++++++++++++++++++++++++++ !* Define Linear Elastic Material Type 1 !*++++++++++++++++++++++++++++++++++++++ mp,ex,1,2.1E12 mp,nuxy,1,0.0 !*+++++++++++++++++++++++++++++++++++++++++++++++++ !* Define Initial Gap, Stable Stiffness, Stress Cap !*+++++++++++++++++++++++++++++++++++++++++++++++++ delta0 = 0.00e-3 stiff0 = 0.0e7 scap = 1.0e-5 tb,gasket,2,,,para tbdata, 1,delta0,stiff0,scap !*++++++++++++++++++++++++++++++++ !* Define Gasket Compression Curve !*++++++++++++++++++++++++++++++++ tb,gask,2,1,13,comp tbpt,,0.460800E-03, 0.161226E+07 tbpt,,0.511600E-03, 0.520884E+07 tbpt,,0.562400E-03, 0.113134E+08 tbpt,,0.613200E-03, 0.200499E+08 tbpt,,0.664000E-03, 0.259960E+08 tbpt,,0.714800E-03, 0.290345E+08 tbpt,,0.765600E-03, 0.357453E+08 tbpt,,0.816400E-03, 0.440064E+08 tbpt,,0.867200E-03, 0.563189E+08 tbpt,,0.918000E-03, 0.748254E+08 tbpt,,0.968800E-03, 0.967287E+08 tbpt,,0.101960E-02, 0.129001E+09 tbpt,,0.109326E-02, 0.157147E+09 !*+++++++++++++++++++++++++++++++++++++ !* Define Gasket Linear Unloading Curve !*+++++++++++++++++++++++++++++++++++++ tb,gask,2,1,5,lunl tbpt,,0.460800E-03, 2.430000E+11 tbpt,,0.714800E-03, 3.565000E+11 tbpt,,0.816400E-03, 5.92300E+11 tbpt,,0.968800E-03, 1.088000e+12 tbpt,,0.109326E-02, 1.490000E+12 !*+++++++++++++++++++++++++++ !* List Gasket Material Model !*+++++++++++++++++++++++++++ tblist,gask,all !*++++++++++++++++++ !* Define Parameters !*++++++++++++++++++ n1 = 20 n2 = n1*100 n3 = n1 dis1 = -0.0008 dis2 = -0.000001 pres = 1.0e7 pres2 = 10 pres3 = 1.4E8 dp = -2.0e7 elb = 1.0 elg = 0.1 !*+++++++++++++++ !* Generate Nodes !*+++++++++++++++ n,1, n,2,1.0 n,3,1.0,1.0 n,4,0.0,1.0 ngen,2,4,1,4,,0.0,0.0,elb ngen,2,8,1,4,,0.0,0.0,elb+elg ngen,2,12,1,4,,0.0,0.0,2*elb+elg !*+++++++++++++++++++++++++++++++++++++++++ !* Generate Front and Back SOLID185 Element !*+++++++++++++++++++++++++++++++++++++++++ et,1,185,,1 mat,1 e,1,2,3,4,5,6,7,8 e,9,10,11,12,13,14,15,16 !*+++++++++++++++++++++++++++++++++ !* Generate Middle INTER195 Element !*+++++++++++++++++++++++++++++++++ et,2,195,, type,2 mat,2 e,5,6,7,8,9,10,11,12 !*++++++++++++++++++++++++++ !* Define Boundary Condition !*++++++++++++++++++++++++++ nsel,s,loc,z d,all,uz nsel,all nsel,s,loc,x d,all,ux nsel,all nsel,s,loc,y d,all,uy nsel,all finish /solu !*+++++++++++++++++++ !* Apply Displacement !*+++++++++++++++++++ nsel,s,loc,z,elb*2+elg d,all,uz,dis1 nsel,all !*+++++++++++++++++++++++++++++++++++++++++++++ !* Solve First Load Step, Compress the Elements !*+++++++++++++++++++++++++++++++++++++++++++++ nsubst,n1,n2,n3 outres,all,all outres,svar,all solve !*++++++++++++++++++++++++++++++++++++++++++ !* Solve Second Load Step, Open the Elements !*++++++++++++++++++++++++++++++++++++++++++ nsubst,n1,n2,n3 outres,all,all outres,svar,all nsel,s,loc,z,elb*2+elg d,all,uz,dis2 nall solve finish !*++++++++++++++++++++++++ !* Postprocess the Results !*++++++++++++++++++++++++ !/post1 !set,last !pres,s !pres,epto !pres,epel !prns,epel !finish !*++++++++++++++++++++++++++++++++++++++++++++++ !* Post26, Print and Plot Gasket Element Results !*++++++++++++++++++++++++++++++++++++++++++++++ /post26 esol,2,3, ,s,x,press esol,3,3, ,epel,x,delta add,4,2, , ,press,,,-1, ! change sign for plotting add,5,3,,,delta,,,-1, ! change sign for plotting prvar,2,3,4,5 xvar,5 plvar,4 finish
Presented below is the POST26 output resulting from this analysis.
------------------------------------------------------------------------
***** POST26 VARIABLE LISTING *****
TIME 3 S X 3 EPELX 4 ADD 5 ADD
press delta press delta
0.50000E-01 -139488. -0.398672E-04 139488. 0.398672E-04
0.10000 -278977. -0.797343E-04 278977. 0.797343E-04
0.15000 -418465. -0.119601E-03 418465. 0.119601E-03
0.20000 -557953. -0.159469E-03 557953. 0.159469E-03
0.25000 -697442. -0.199336E-03 697442. 0.199336E-03
0.30000 -836930. -0.239203E-03 836930. 0.239203E-03
0.35000 -976418. -0.279070E-03 976418. 0.279070E-03
0.40000 -0.111591E+07 -0.318937E-03 0.111591E+07 0.318937E-03
0.45000 -0.125539E+07 -0.358804E-03 0.125539E+07 0.358804E-03
0.50000 -0.139488E+07 -0.398672E-03 0.139488E+07 0.398672E-03
0.55000 -0.153437E+07 -0.438539E-03 0.153437E+07 0.438539E-03
0.60000 -0.278389E+07 -0.477349E-03 0.278389E+07 0.477349E-03
0.65000 -0.557968E+07 -0.514686E-03 0.557968E+07 0.514686E-03
0.70000 -0.989280E+07 -0.550578E-03 0.989280E+07 0.550578E-03
0.75000 -0.152775E+08 -0.585450E-03 0.152775E+08 0.585450E-03
0.80000 -0.208613E+08 -0.620132E-03 0.208613E+08 0.620132E-03
0.85000 -0.250737E+08 -0.656120E-03 0.250737E+08 0.656120E-03
0.90000 -0.277640E+08 -0.693558E-03 0.277640E+08 0.693558E-03
0.95000 -0.310936E+08 -0.730387E-03 0.310936E+08 0.730387E-03
1.0000 -0.357955E+08 -0.765909E-03 0.357955E+08 0.765909E-03
1.0500 -0.227277E+08 -0.738405E-03 0.227277E+08 0.738405E-03
1.1000 -0.965988E+07 -0.710900E-03 0.965988E+07 0.710900E-03
1.1500 -0.100000E-04 -0.680150E-03 0.100000E-04 0.680150E-03
1.2000 -0.100000E-04 -0.640200E-03 0.100000E-04 0.640200E-03
1.2500 -0.100000E-04 -0.600250E-03 0.100000E-04 0.600250E-03
1.3000 -0.100000E-04 -0.560300E-03 0.100000E-04 0.560300E-03
1.3500 -0.100000E-04 -0.520350E-03 0.100000E-04 0.520350E-03
1.4000 -0.100000E-04 -0.480400E-03 0.100000E-04 0.480400E-03
1.4500 -0.100000E-04 -0.440450E-03 0.100000E-04 0.440450E-03
1.5000 -0.100000E-04 -0.400500E-03 0.100000E-04 0.400500E-03
1.5500 -0.100000E-04 -0.360550E-03 0.100000E-04 0.360550E-03
1.6000 -0.100000E-04 -0.320600E-03 0.100000E-04 0.320600E-03
1.6500 -0.100000E-04 -0.280650E-03 0.100000E-04 0.280650E-03
1.7000 -0.100000E-04 -0.240700E-03 0.100000E-04 0.240700E-03
1.7500 -0.100000E-04 -0.200750E-03 0.100000E-04 0.200750E-03
1.8000 -0.100000E-04 -0.160800E-03 0.100000E-04 0.160800E-03
1.8500 -0.100000E-04 -0.120850E-03 0.100000E-04 0.120850E-03
1.9000 -0.100000E-04 -0.809000E-04 0.100000E-04 0.809000E-04
1.9500 -0.100000E-04 -0.409500E-04 0.100000E-04 0.409500E-04
2.0000 -0.100000E-04 -0.100000E-05 0.100000E-04 0.100000E-05