$ fmatrx=2, then springback is complete! $ boost displacement higher to see if results are still reasonable >> they are if FMATRX=2 $ load and release $ solid forms 1, 2, and -2 all are OK *KEYWORD *CONTROL_SOLID $$ set fmatrx to 2 ,2 *comment I've come to the conclusion that the damping energy associated with mat 2, 77, 181's frequency-independent material damping variables G and SIGF is included in the material internal energy. This is based on the attached test case where the final z-stress is damped to zero but the final internal energy (representing energy dissipated by damping) is the same as the internal energy at peak loading between t=0.01 and t=0.025. In this test case, the load is abruptly released at t=0.025. A similar thing happens when using *damping_part_stiffness instead of G and SIGF. Four cases are run by including the word "case" on the execution line. case0: no damping case1: stiffness damping case2: freq indep material damping with G and SIGF; fit to curve case3: freq indep material damping with G and SIGF; C values from case2.d3hsp used Compare: - IE from the four glstats (or four matsums) - z-stress from the four elouts jd Ticket#2018050910000084 Note G and SIGF values not echoed in case3.d3hsp but z-stress results are identical to case2 (so just a d3hsp oversight) (used version dev, r129119) *case_begin_0 *title no damping *mat_hyperelastic_rubber 1,1.16e-7,.496, 1 1,1,1,99 *case_end_0 *case_begin_1 *title stiffness damping *CONTROL_ENERGY 2,2,2,2 *damping_part_stiffness $1,0.1 1,0.05 *mat_hyperelastic_rubber 1,1.16e-7,.496, 1 1,1,1,99 *case_end_1 *case_begin_2 *title freq indep material damping *mat_hyperelastic_rubber $1,1.16e-7,.496, 1 $$ with G and SIGF in fields 6,7 $1,1.16e-7,.496, 1, , 10, 0.01 1,1.16e-7,.496, 1, , 5, 0.005 1,1,1,99 *case_end_2 *case_begin_3 *title freq indep material damping *mat_hyperelastic_rubber $1,1.16e-7,.496, 1 $$ with G and SIGF in fields 6,7 $$ C values directly 1,1.16e-7,.496, , , 5, 0.005 $ Mooney constant c1 = 0.1584E+01 $ Mooney constant c2 = -0.7834E+00 0.1584E+1,-0.7834 *case_end_3 *database_matsum 1.e-4 *database_glstat 1.e-4 *database_elout 1.e-4 *database_history_solid 1 *database_nodout 1.e-4 *database_history_node 5 *database_bndout 0.001 *DEFINE_CURVE $^ $ LCID SIDR SFA SFO OFFA OFFO DATTYP 99 $ A1 O1 -.4,-1.4 0,0 0.4,1.4 0.8,2.8 1.2,4.2 1.6,6.1 2.0,8.6 $2.4,13 $2.6,16 $3,40 $---------------------------------------------------------------------- $---------------------------------------------------------------------- *TITLE m77_h *SET_NODE_LIST 1 1 2 3 4 *SET_SOLID_LIST 1 1 *CONTROL_TERMINATION 0.05 *CONTROL_TIMESTEP $,.5 ,.3 *DATABASE_BINARY_D3PLOT 1.000E-04 *SECTION_SOLID $1, 2 $1,-2 1,1 *CONTROL_HOURGLASS 6,.1 *PART 1 1 1 0 *NODE 1 0.000000000E+00 0.000000000E+00 0.000000000E+00 3 0 2 5.000000000E-01 0.000000000E+00 0.000000000E+00 3 0 3 0.000000000E+00 5.000000000E-01 0.000000000E+00 3 0 4 5.000000000E-01 5.000000000E-01 0.000000000E+00 3 0 5 0.000000000E+00 0.000000000E+00 5.000000000E-01 0 0 6 5.000000000E-01 0.000000000E+00 5.000000000E-01 0 0 7 0.000000000E+00 5.000000000E-01 5.000000000E-01 0 0 8 5.000000000E-01 5.000000000E-01 5.000000000E-01 0 0 *ELEMENT_SOLID 1 1 1 2 4 3 5 6 8 7 *DEFINE_CURVE $ 1 0 0.000E+00 1. $$ scale displ by 2, can clearly see that springback to undeformed state is not complete UNLESS $$ fmatrx=2 $ 1 0 0.000E+00 2. 1 0 0.000E+00 4. 0.00000000E+00 0.00000000E+00 0.010000000000 -.2 1. -.2 *BOUNDARY_PRESCRIBED_MOTION_NODE 5 3 2 1 0.100E+00 0 0.025 7 3 2 1 0.100E+00 0 0.025 6 3 2 1 0.100E+00 0 0.025 8 3 2 1 0.100E+00 0 0.025 *END