*HEADING
 1D transient wave propagation, acoustic medium, incident wave load, planar
 and defined through acceleration amplitude
**
** C = root (K/rho)= 343.05 m/s   K=bulk mod, rho=density.  
**
** Analytical solution to prescribed constant acceleration of a0 at z=0
** 
** p(z,t) = (K a0 / c^2) (ct - z)  for z < ct
**        = 0  			   for z > ct
** 
*PREPRINT,ECHO=NO,HISTORY=NO,MODEL=YES
*NODE, NSET=ODB_NSET
    1, 0,
  101, 0, 1.,
  501, .5E-2,0.
  601, .5E-2,1.
 1001, 1.E-2,0.
 1101, 1.E-2,1.
*NGEN,NSET=CHANNEL
    1,101
  501,601
 1001,1101
*NSET,NSET=SAMPLE,GENERATE
 1,101
*ELEMENT,TYPE=ACAX6
 1,1,1001,1003,501,1002,502
 2,1,1003,3,502,503,2
*ELGEN,ELSET=CHANNEL
 1,50,2,2
 2,50,2,2
**************************
*SURFACE,NAME=IW_LOAD
1,S1
**************************
** CROSS-SECTION IS Pi*1.0E-4
*SOLID SECTION,MATERIAL=AIR,ELSET=CHANNEL
1.E-2, 
*MATERIAL,NAME=AIR
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
**
**************************
*INCIDENT WAVE PROPERTY,NAME=IWPROP,TYPE=PLANE
0.0,0.0,
0.0,-10.0,
*INCIDENT WAVE FLUID PROPERTY
0.1424E6,1.21,0.0
*AMPLITUDE,DEFINITION=TABULAR,NAME=ACCVTIME
0.0,-1.0,1.0,-1.0
**************************
*RESTART,WRITE
**
*STEP,INC=1000
*DYNAMIC
.0001,.0044
** DEFINE NONREFLECTIVE BOUNDARY AT Z=1
*IMPEDANCE
 100,I2
**
*INCIDENT WAVE,ACCELERATIONAMPLITUDE=ACCVTIME,PROPERTY=IWPROP
IW_LOAD,1
**
*EL PRINT,FREQ=0
*NODE PRINT,NSET=SAMPLE,FREQ=22
 POR, 
*OUTPUT,FIELD,FREQUENCY=1
*NODE OUTPUT
 POR,
*OUTPUT,HISTORY,FREQUENCY=1
*NODE OUTPUT,NSET=SAMPLE
 POR,
*ENDSTEP