*HEADING Single element model to test fit of hyperelastic test data *NODE,NSET=ALL 1, 2,1. 3,1.,1., 4,0.,1., 5,0.,0.,1. 6,1.,0.,1. 7,1.,1.,1. 8,0.,1.,1. *NSET,NSET=FACE1 1,2,3,4 *NSET,NSET=FACE2 5,6,7,8 *NSET,NSET=FACE3 1,2,5,6 *NSET,NSET=FACE4 2, *NSET,NSET=FACE42 3,6,7 *NSET,NSET=FACE5 3,4,7,8 *NSET,NSET=FACE6 4,1,8,5 *EQUATION ** ** Since the S11 output is Cauchy or true stress, we need to ** determine the nominal stress for post-processing. ** Nodes 3,6,7 are tied to node 2 in dof 1 so that: ** Nominal stress (dof 1) = RF1 (@ node 2) / Original area ** (w/c is 1 x 1 = 1) 2, FACE42,1,1, 2,1,-1 *ELEMENT,TYPE=C3D8RH,ELSET=ONE 1,1,2,3,4,5,6,7,8 *SOLID SECTION,ELSET=ONE,MATERIAL=TREL *MATERIAL,NAME=TREL ** ** To use the OGDEN model, simply replace the POLYNOMIAL ** parameter with the OGDEN parameter. ** To change the strain energy function order, change the N ** parameter. ** *HYPERELASTIC,N=1,POLYNOMIAL,TEST DATA INPUT *UNIAXIAL TEST DATA 0.054E6, 0.038 0.152E6, 0.1338 0.254E6, 0.221 0.362E6, 0.345 0.459E6, 0.46 0.583E6, 0.6242 0.656E6, 0.851 0.73E6, 1.4268 *BIAXIAL TEST DATA 0.089E6, 0.0200 0.255E6, 0.1400 0.503E6, 0.4200 0.958E6, 1.4900 1.703E6, 2.7500 2.413E6, 3.4500 *PLANAR TEST DATA 0.055E6, 0.0690 0.324E6, 0.2828 0.758E6, 1.3862 1.269E6, 3.0345 1.779E6, 4.0621 ** ** In every step the step time and magnitude of displacement are ** equal so that history plots of RF at node 2 actually ** correspond to nominal strain vs nominal stress. ** *STEP,NLGEOM,INC=50000 Step 1: Uniaxial Tension *STATIC,DIRECT .02, 1.8 *BOUNDARY,OP=NEW FACE1,3 FACE3,2 FACE6,1 FACE4,1,1, 1.8 *ENERGY PRINT *EL PRINT,FREQUENCY=500 S, E, *NODE PRINT,FREQUENCY=500 U,RF *OUTPUT,FIELD, OP=ADD,FREQUENCY=1 *NODE OUTPUT U *OUTPUT,HISTORY,OP=ADD,FREQUENCY=1 *NODE OUTPUT, NSET=ALL U,RF1,RF2 *END STEP ** ** *STEP,NLGEOM,INC=20 Step 2: Unload *STATIC,DIRECT .1, 1.8 *BOUNDARY,OP=MOD FACE4,1 *OUTPUT,FIELD, OP=NEW,FREQUENCY=0 *OUTPUT,HISTORY,OP=NEW,FREQUENCY=0 *END STEP ** ** *STEP,NLGEOM,INC=500 Step 3: Biaxial Tension *STATIC,DIRECT .02, 1.7 *BOUNDARY,OP=NEW FACE1,3 FACE3,2 FACE6,1 FACE4,1,1, 1.7 FACE5,2,2, 1.7 *ENERGY PRINT *EL PRINT,FREQUENCY=500 S, E, *NODE PRINT,FREQUENCY=500 U,RF *OUTPUT,FIELD, OP=ADD,FREQUENCY=1 *NODE OUTPUT U *OUTPUT,HISTORY,OP=ADD,FREQUENCY=1 *NODE OUTPUT, NSET=ALL U,RF1,RF2 *END STEP *STEP,NLGEOM,INC=20 Step 4: Unload *STATIC,DIRECT .1, 1.7 *BOUNDARY,OP=MOD FACE4,1,1, FACE5,2,2, *OUTPUT,FIELD, OP=NEW,FREQUENCY=0 *OUTPUT,HISTORY,OP=NEW,FREQUENCY=0 *END STEP *STEP,NLGEOM,INC=500 Step 5: Planar Tension (Pure Shear) *STATIC,DIRECT .02, 1.8 *BOUNDARY,OP=NEW FACE1,3 FACE3,2 FACE5,2 FACE6,1 FACE4,1,1, 1.8 *ENERGY PRINT *EL PRINT,FREQUENCY=500 S, E, *NODE PRINT,FREQUENCY=500 U,RF *OUTPUT,FIELD, OP=ADD,FREQUENCY=1 *NODE OUTPUT U *OUTPUT,HISTORY,OP=ADD,FREQUENCY=1 *NODE OUTPUT, NSET=ALL U,RF1,RF2 *END STEP