*HEADING EC28AFAD: AC2D8 ELEMENTS Acoustic test - 1D Problem, SS-DIRECT. A 4m long tube; from left to right, a sound source, 3m is air, then 1m of a highly absorbent material, followed by a rigid termination. *PREPRINT,ECHO=NO,HISTORY=NO,MODEL=NO *RESTART,WRITE *********************************************************** ** ** ** Mesh Generation ** *NODE, Nset=ODB_NSET 1,0, 401,4, 501,0, 1E-2 901,4, 1E-2 1001,0, 2E-2 1401,4, 2E-2 *NGEN,NSET=ALL 1,401 501,901 1001,1401 *NSET,NSET=QA_TEST,GENERATE 1,401 *NSET,NSET=LOAD 1,501,1001 *ELEMENT,TYPE=AC2D8 1,1,3,1003,1001,2,503,1002,501 *ELGEN,ELSET=CHANNEL 1,150,2 *ELEMENT,TYPE=AC2D8 151,301,303,1303,1301,302,803,1302,801 *ELGEN,ELSET=ABSORB 151,50,2 ** ** ************************************************ ** ** ELEMENT PROPERTIES ** ** *SOLID SECTION,MATERIAL=AIR,ELSET=CHANNEL *SOLID SECTION,MATERIAL=ABSORB,ELSET=ABSORB ** ** *MATERIAL,NAME=AIR *DENSITY 1.21, *ACOUSTIC MEDIUM,BULK MODULUS 0.1424E6, ** ** *MATERIAL,NAME=ABSORB *DENSITY 1.21, *ACOUSTIC MEDIUM,BULK MODULUS 0.1424E6, *ACOUSTIC MEDIUM,VOLUMETRIC DRAG 1e4, ** ** ** ************************************************* ** *Elset,Elset=ODB_ESET CHANNEL, ABSORB ** ** *Nset, Nset=ODB_NSET ODB_NSET, ALL, QA_TEST ** ** *STEP *STEADY STATE DYNAMICS,DIRECT,FREQUENCY SCALE=LINEAR 100,1100,3,1 ** ** Prescribe outward acceleration of 100 at node LOAD ** To prescribe a total outward volume acceleration ** of 1 on the face with area 2/100, the load must be ** distributed in the ratios (1/6,2/3,1/6) to the ** (corner, midside, corner) nodes, respectively *CLOAD 1,8, -.33333 501,8, -1.33333 1001,8, -.33333 ** *NODE PRINT, NSET=QA_TEST POR,PPOR, *EL PRINT,FREQUENCY=0 *ENERGYPRINT *OUTPUT,FIELD *NODE OUTPUT,NSET=QA_TEST POR, *ELEMENT OUTPUT ACV,INTEN,GRADP,ENER,ELEN,ELEDEN *OUTPUT,HISTORY *NODE OUTPUT,NSET=QA_TEST POR, *ENERGY OUTPUT ALLSE,ALLKE,ALLWK,ALLVD *ENDSTEP ** ** *STEP *FREQUENCY,NORM=MASS,EIGENSOLVER=LANCZOS, SIM=NO 50, , , *NODE PRINT,F=0 *EL PRINT,F=0 *OUTPUT,FIELD,Frequency=0 *END STEP ** ** *STEP *STEADY STATE DYNAMICS,SUBSPACE PROJECTION=ALL,FREQUENCY SCALE=LINEAR,INTERVAL=RANGE 100,1100,3,1 ** ** Prescribe outward acceleration of 100 at node LOAD ** To prescribe a total outward volume acceleration ** of 1 on the face with area 2/100, the load must be ** distributed in the ratios (1/6,2/3,1/6) to the ** (corner, midside, corner) nodes, respectively *CLOAD 1,8, -.33333 501,8, -1.33333 1001,8, -.33333 ** *NODE PRINT, NSET=QA_TEST POR,PPOR, *EL PRINT,FREQUENCY=0 *energyprint *OUTPUT,FIELD,VARIABLE=PRESELECT,OP=ADD,FREQUENCY=9999 *OUTPUT,FIELD, OP=ADD *NODE OUTPUT,NSET=QA_TEST POR, *ELEMENT OUTPUT,ELSET=ABSORB ACV,INTEN,GRADP *OUTPUT,HISTORY *NODE OUTPUT,NSET=QA_TEST POR, *ENERGY OUTPUT ALLSE,ALLKE,ALLWK,ALLVD *ENDSTEP