Nonlinear Spring-Mass-System

A mass is attached to a nonlinear spring. Period of vibration is determined. Example 18 from Introductory Manual for LS-DYNA Users by James M. Kennedy.

*BOUNDARY_SPC_NODE
*CONTROL_TERMINATION
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3PLOT
*DATABASE_HISTORY_NODE
*DATABASE_NODOUT
*DEFINE_CURVE
*ELEMENT_DISCRETE
*ELEMENT_MASS
*END
*KEYWORD
*MAT_SPRING_NONLINEAR_ELASTIC
*NODE
*PART
*SECTION_DISCRETE
*TITLE

*KEYWORD
*TITLE
Natural Frequency of a Nonlinear Spring-Mass System
*CONTROL_TERMINATION
  0.150000         0       0.0       0.0       0.0
*CONTROL_TIMESTEP
 1.000e-04 1.000e-04         0       0.0       0.0         0         0         0
       0.0         0         0
*DATABASE_NODOUT
  0.000100
*DATABASE_BINARY_D3PLOT
  0.001000
*DATABASE_HISTORY_NODE
         1
*PART
         1         1         1
*SECTION_DISCRETE
         1         0       0.0       0.0       0.0       0.0
       0.0       0.0
*MAT_SPRING_NONLINEAR_ELASTIC
         1         1
*DEFINE_CURVE
         1         0  1.000000  1.000000       0.0       0.0
                0.00              0.0000
                0.10              0.2040
                0.20              0.4320
                0.30              0.7080
                0.40              1.0240
                0.50              1.5000
                0.60              2.0640
                0.70              2.7720
                0.80              3.6480
                0.90              4.7160
                1.00              6.0000
*ELEMENT_DISCRETE
*ELEMENT_MASS
*NODE
*BOUNDARY_SPC_NODE
         2         0         1         1         1         1         1         1
*END