*HEADING
 EC3AAFAS: AC3D10 and ASI elements
 1D transient wave propagation in an acoustic medium
 prescribed acceleration on dof. 1.
 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=YES,MODEL=YES
**
*part,name=old
*NODE, Nset=ODB_NSET
    1, 0,
  101, 1,
  501, 0,.5e-2
  601, 1,.5e-2
 1001, 0, 1.e-2
 1101, 1, 1.e-2
 1501, 0, 1.e-2, -1.e-2
 1601, 1, 1.e-2, -1.e-2
 2001, 0, 1.e-2, -0.5e-2
 2101, 1, 1.e-2, -0.5e-2
 2501, 0, 0, -1.e-2
 2601, 1, 0, -1.e-2
 3001, 0,.5e-2, -1.e-2
 3101, 1,.5e-2, -1.e-2
 3501, 0, 0, -0.5e-2
 3601, 1, 0, -0.5e-2
 4001, 0, 0.5e-2, -0.5e-2
 4101, 1, 0.5e-2, -0.5e-2
*NGEN,NSET=CHANNEL
    1,101
  501,601
 1001,1101
 1501,1601
 2001,2101
 2501,2601
 3001,3101
 3501,3601
 4001,4101
*NSET,NSET=SAMPLE,GENERATE
 1,101
*NSET,NSET=LOAD
 1,1001,1501,2501,501,2001,3001,3501
*NSET,NSET=LOADED
 1,1001,1501,2501
*ELEMENT,TYPE=AC3D10
    1,    1, 2501, 1001,    3, 3501, 4001,  501,
            2, 3502,  502,
    2, 2501, 1001,    3, 2503, 4001,  502, 3502,
         2502, 4002, 3503,
    3, 1001,    3, 2503, 1003,  502, 3503, 4002,
         1002,  503, 4003,
    4, 1001, 2501, 1501, 1003, 4001, 3001, 2001,
         1002, 4002, 2002,
    5, 2501, 1501, 1003, 2503, 3001, 2002, 4002,
         2502, 3002, 4003,
    6, 1501, 1003, 2503, 1503, 2002, 4003, 3002,
         1502, 2003, 3003,
*ELGEN,ELSET=CHANNEL
 1,50,2,6
 2,50,2,6
 3,50,2,6
 4,50,2,6
 5,50,2,6
 6,50,2,6
*SOLID SECTION,MATERIAL=AIR,ELSET=CHANNEL
**
** degenerated ASI4 elements used - ASI3 is a line element.
**
*ELEMENT,TYPE=ASI4,ELSET=LOAD
 900,1,2501,1001,1001
 901,2501,1501,1001,2501
*INTERFACE, ELSET=LOAD
*endpart
*part,name=new
*NODE, Nset=ODB_NSET
    1, 0,
  101, 1,
  501, 0,.5e-2
  601, 1,.5e-2
 1001, 0, 1.e-2
 1101, 1, 1.e-2
 1501, 0, 1.e-2, -1.e-2
 1601, 1, 1.e-2, -1.e-2
 2001, 0, 1.e-2, -0.5e-2
 2101, 1, 1.e-2, -0.5e-2
 2501, 0, 0, -1.e-2
 2601, 1, 0, -1.e-2
 3001, 0,.5e-2, -1.e-2
 3101, 1,.5e-2, -1.e-2
 3501, 0, 0, -0.5e-2
 3601, 1, 0, -0.5e-2
 4001, 0, 0.5e-2, -0.5e-2
 4101, 1, 0.5e-2, -0.5e-2
*NGEN,NSET=CHANNEL
    1,101
  501,601
 1001,1101
 1501,1601
 2001,2101
 2501,2601
 3001,3101
 3501,3601
 4001,4101
*NSET,NSET=SAMPLE,GENERATE
 1,101
*NSET,NSET=LOAD
 1,1001,1501,2501,501,2001,3001,3501,4001,
*ELEMENT,TYPE=AC3D10
    1,    1, 2501, 1001,    3, 3501, 4001,  501,
            2, 3502,  502,
    2, 2501, 1001,    3, 2503, 4001,  502, 3502,
         2502, 4002, 3503,
    3, 1001,    3, 2503, 1003,  502, 3503, 4002,
         1002,  503, 4003,
    4, 1001, 2501, 1501, 1003, 4001, 3001, 2001,
         1002, 4002, 2002,
    5, 2501, 1501, 1003, 2503, 3001, 2002, 4002,
         2502, 3002, 4003,
    6, 1501, 1003, 2503, 1503, 2002, 4003, 3002,
         1502, 2003, 3003,
*ELGEN,ELSET=CHANNEL
 1,50,2,6
 2,50,2,6
 3,50,2,6
 4,50,2,6
 5,50,2,6
 6,50,2,6
*SOLID SECTION,MATERIAL=AIR,ELSET=CHANNEL
**
** degenerated ASI4 elements used - ASI3 is a line element.
**
*ELEMENT,TYPE=ASI3D6,ELSET=LOAD
 900, 1,2501,1001, 3501,4001,501
 901, 2501,1501,1001, 3001,2001,4001
*INTERFACE, ELSET=LOAD
*endpart
**
*assembly,name=both
*instance,name=old,part=old
*endinstance
*instance,name=new,part=new
0,0.05,0
*endinstance
*nset,nset=sample
old.sample,new.sample
*nset,nset=load
old.load,new.load
*surface,NAME=NRS
 old.300,S3,
 old.297,S3
 new.300,S3,
 new.297,S3,
*endassembly
**************************************
*MATERIAL,NAME=AIR
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
**
**
*RESTART,WRITE
**
*STEP,INC=1000
*DYNAMIC
.0001,.0036
** Define nonreflective boundary at x=1
*IMPEDANCE
 old.300,I3
 old.297,I3
 new.300,I3
 new.297,I3
**
**  Prescribe unit _particle_ acceleration a0 inwards;
**
*BOUNDARY,TYPE=ACCELERATION
 LOAD,1,1,1.
*EL PRINT,FREQ=0
*NODE PRINT,NSET=SAMPLE,FREQ=6
 POR,
*NODE FILE,NSET=SAMPLE,FREQ=6
 POR,
*OUTPUT,FIELD, OP=NEW,Frequency=6
*NODE OUTPUT
 POR,
*OUTPUT,HISTORY,OP=ADD,Frequency=6
*NODE OUTPUT,NSET=SAMPLE
 POR,
*ENDSTEP
***********************
*STEP,INC=1000
*DYNAMIC
.0001,.0008
*IMPEDANCE,OP=NEW
*SIMPEDANCE
 NRS,
*BOUNDARY,TYPE=ACCELERATION
 LOAD,1,1,1.
*EL PRINT,FREQ=0
*NODE PRINT,NSET=SAMPLE,FREQ=6
 POR,
*NODE FILE,NSET=SAMPLE,FREQ=6
 POR,
*OUTPUT,FIELD, OP=NEW,Frequency=6
*NODE OUTPUT
 POR,
*OUTPUT,HISTORY,OP=ADD,Frequency=6
*NODE OUTPUT,NSET=SAMPLE
 POR,
*ENDSTEP