*HEADING
1D TRANSIENT WAVE PROPAGATION IN AN ACOUSTIC MEDIUM WITH CLOAD 
IN ABAQUS/EXPLICIT [AC3D4]; 
VERIFICATION PROBLEM: TRANSIENT DYNAMICS TESTS
**
** C=SQRT(K/RHO)= 343.05 M/S   K=BULK MODULUS, 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
** FOR EXAMPLE AT THE END OF THE SIMULATION : 
**              P_1(0,0.0044)=1.826
**              P_51(0.5,0.0044)=1.221
**              P_101(1.0,0.0044)=0.616
** THE ACCELERATION IS SPECIFIED USING *CLOAD ON DOF 8
**
** SEE CH. 3.7.7 OF ABAQUS/VERIFICATION MANUAL
**
*PREPRINT,ECHO=NO,HISTORY=NO,MODEL=YES
*NODE, Nset=NALL
    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=NALL
    1,101
 1001,1101
 1501,1601
 2501,2601
*NSET,NSET=QA_TEST,GEN
1,10,1
45,55,1
90,101,1
*NSET,NSET=NOUT
QA_TEST,
*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,NUMBER=1
*STEP
*DYNAMIC,EXPLICIT
,.0044
*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
**
**
*************************
*OUTPUT,FIELD,NUMBER INTERVAL=1
*NODE OUTPUT
POR
*NODE OUTPUT,NSET=QA_TEST
POR,
*************************
***OUTPUT,HISTORY, TIME INTERVAL=0.00022
***NODE OUTPUT, NSET=NOUT
**POR
*************************
*END STEP