*HEADING
 1D transient wave propagation in an acoustic medium with CLOAD on dof 8. AC3D4
 Verification problem: Transient Dynamics Tests.
**
** C = root (K/rho)= 343.05 m/s   K=bulk mod, rho=density.  
**
** Analytic solution to prescribed constant acceleration of a0 at x=0
** 
** p(x,t) = (K a0 / c^2) (ct - x)  for x < ct
**        = 0  			   for x > ct
** 
*PREPRINT,ECHO=NO,HISTORY=NO,MODEL=no
*NODE, Nset=ODB_NSET
    1, 0,
  101, 1,
 1001, 0, 1e-2
 1101, 1, 1e-2
 1501, 0, 1e-2, -1e-2
 1601, 1, 1e-2, -1e-2
 2501, 0, 0, -1e-2
 2601, 1, 0, -1e-2
*NGEN,NSET=CHANNEL_NODES
    1,101
 1001,1101
 1501,1601
 2501,2601
*NSET,NSET=SAMPLE_NODES,GENERATE
 1,101
*NSET,NSET=LOADED_NODES
 1,1001,1501,2501
*ELEMENT,TYPE=AC3D4
    1,    1, 1002,    2, 2501
    2, 1002,    2, 2501, 1502
    3,    2, 2501, 1502, 2502
    4,    1, 1001, 1002, 2501
    5, 1001, 1002, 2501, 1501
    6, 1002, 2501, 1501, 1502
*ELGEN,ELSET=CHANNEL
 1,100,1,6
 2,100,1,6
 3,100,1,6
 4,100,1,6
 5,100,1,6
 6,100,1,6
*SOLID SECTION,MATERIAL=AIR,ELSET=CHANNEL
**
*MATERIAL,NAME=AIR
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
**
** Define nonreflective boundary at x=1
** Using user calculated constants:
** 1/k1=0, 1/c1=1/(rho*c)
*IMPEDANCE PROPERTY,NAME=NONREF
 0, 2.41E-3
**
*RESTART,WRITE
**
**
** Sets added by addodb
**
*Elset,Elset=ODB_ESET
CHANNEL,
**
**
*Nset, Nset=ODB_NSET
ODB_NSET, CHANNEL_NODES, SAMPLE_NODES, LOADED_NODES
**
**
*STEP,INC=1000
*DYNAMIC
.0001,.0044,,0.0001
*IMPEDANCE,prop=nonref
 597,I4,
 596,I2,
**
** Prescribe unit particle acceleration a0, inwards,
** so that _volume_ acceleration is a0*surface area.
**  Distribute 1/4 to each corner node:   
*CLOAD
 LOADED_NODES,8,.25e-4
**
*EL PRINT,FREQ=0
*NODE PRINT,NSET=SAMPLE_NODES,FREQ=22
 POR,
*NODE FILE,NSET=SAMPLE_NODES,FREQ=22
 POR,
*OUTPUT,FIELD,VARIABLE=PRESELECT,OP=ADD,FREQUENCY=9999
*OUTPUT,FIELD, OP=ADD,Frequency=22
*NODE OUTPUT,NSET=SAMPLE_NODES
 POR,
*OUTPUT,HISTORY,OP=ADD,Frequency=22
*NODE OUTPUT,NSET=SAMPLE_NODES
 POR,
*ENDSTEP