*HEADING EB2HRXE3: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED PATCH OF ELEMENTS [B21H] *NODE 1, 4,10.0 *NGEN 1,4 *ELEMENT,TYPE=B21H 1, 1,2 *ELGEN,ELSET=ALL 1,3,1,1 *BEAM SECTION,SECTION=RECT,ELSET=ALL,MATERIAL=MAT 0.1,0.1 *MATERIAL,NAME=MAT *ELASTIC 30E6,0.0 *DENSITY 7.5E-4, *STEP,PERTURBATION *FREQUENCY, eigensolver=lanczos, SIM=NO 9, , ,-1.E4 *NODE PRINT U, *END STEP