*HEADING EC24AFAD: AC2D4 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, 1001,0, 2E-2 1401,4, 2E-2 *NGEN,NSET=ALL 1,401 1001,1401 *NSET,NSET=QA_TEST,GENERATE 1,401,10 *NSET,NSET=LOAD 1,1001 *ELEMENT,TYPE=AC2D4 1,1,2,1002,1001 *ELGEN,ELSET=CHANNEL 1,300 *ELEMENT,TYPE=AC2D4 301,301,302,1302,1301 *ELGEN,ELSET=ABSORB 301,100 ** ** ************************************************ ** ** 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 loaded nodes. ** The tributary area of each node is 1/100, so the ** outward volume acceleration is 1. *CLOAD LOAD,8, -1 ** *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=EIGENFREQUENCY,FREQUENCY SCALE=LINEAR,INTERVAL=RANGE 100,1100,3,1 ** ** Prescribe outward acceleration of 100 at loaded nodes. ** The tributary area of each node is 1/100, so the ** outward volume acceleration is 1. *CLOAD LOAD,8, -1 ** *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