*HEADING : EIGENVALUE ANALYSIS OF AN UNCONSTRAINED PATCH OF ELEMENTS [CPEG8RH] *PREPRINT,ECHO=YES,HISTORY=NO,MODEL=NO *NODE 1000,0,0 10,0,0 20,.24,0. 30,.24,.12 40,0.,.12 50,.12,0. 60,.24,.06 70,.12,.12 80,.0,.06 102,.04,.02 104,.18,.03 204,.16,.08 202,.08,.08 *NGEN 102,104 202,204 102,202,50 104,204,50 10,102,46 40,202,81 30,204,87 20,104,42 10,40,15 *ELEMENT,TYPE=CPEG8RH,ELSET=EALL 1, 10, 20,104,102, 50, 62,103, 56 2, 10,102,202, 40, 56,152,121, 80 3,102,104,204,202,103,154,203,152 4,104, 20, 30,204, 62, 60,117,154 5,202,204, 30, 40,203,117, 70,121 *SOLID SECTION,MATERIAL=A1,ELSET=EALL,REFNODE=1000 .001, *MATERIAL,NAME=A1 *ELASTIC,TYPE=ISOTROPIC 1.E6,.25 *DENSITY 7.5E-4, *NSET,NSET=SIDES,GENERATE 10,80,10 *STEP *FREQUENCY, eigensolver=lanczos, SIM=NO 5, , ,-1.E7 *MODAL FILE *OUTPUT,HISTORY,FREQUENCY=1 *MODAL OUTPUT *CONTROLS,PARAMETERS=FIELD 1.E-14, 1., , , 1.E-12 *END STEP *STEP,NLGEOM *STATIC *DLOAD 1, P1, -10000. 2, P4, -10000. 4, P2, -10000. 5, P3, -10000. *BOUNDARY 10,1,2 20,2 *EL PRINT,FREQ=0 *NODE PRINT U, RF, *END STEP *STEP,NLGEOM *FREQUENCY, eigensolver=lanczos, SIM=NO 5, , , -1.E7 *MODAL FILE *OUTPUT,HISTORY,FREQUENCY=1 *MODAL OUTPUT *EL PRINT,FREQ=0 *NODE PRINT,FREQ=0 *BOUNDARY,OP=NEW *END STEP