主轴模态分析，无法添加轴承弹簧单元

西河晋阳

现在想利用APDL分析主轴模态，轴承部分等效为弹簧处理，但是命令流无法添加轴承单元，想请教一下大家。
具体代码如下：
P_RO                = 8860    ! density of the rotor material, kg.m^-3
P_PEX               = 1.95e11 ! elastic modulus of the rotor material, Pa
P_POISSON           = 0.31    ! Poisson's ratio of the rotor material

P_BEARING_STIFFNESS = 8e7  ! Stiffness coefficients of the roller bearing.

! P_ANALYSIS_TYPE = C_ANALYSIS_TYPE_MODAL
P_ANALYSIS_TYPE = C_ANALYSIS_TYPE_UNB_RES

! ================== End of user defined parameters ===============
! ========================= 1. Pre-process ===========================

/PREP7

! == 1.2 == rotor material configuration
P_PGXY = P_PEX/(2*(1+P_POISSON))

MP,   EX, 1, P_PEX
MP, DENS, 1, P_RO
MP,  GXY, 1, P_PGXY
! MP, DMPR, 1, 0.005

! == 1.3 == prepare data for BEAM188 elements
! Set element type
ET, 1, BEAM188, , , 2

P_NELEMENTS = 10 ! total number of rotor elements

P_NRADII = P_NELEMENTS
! outer radii array
*DIM, P_ORADIUS, ARRAY, P_NRADII
P_ORADIUS(1)  = 0.058
P_ORADIUS(2)  = 0.058
P_ORADIUS(3)  = 0.058
P_ORADIUS(4)  = 0.062
P_ORADIUS(5)  = 0.070
P_ORADIUS(6)  = 0.076
P_ORADIUS(7)  = 0.066
P_ORADIUS(8)  = 0.066
P_ORADIUS(9)  = 0.066
P_ORADIUS(10) = 0.066

! inner radii array
*DIM, P_IRADIUS, ARRAY, P_NRADII
P_IRADIUS(1)  = 0.032
P_IRADIUS(2)  = 0.032
P_IRADIUS(3)  = 0.032
P_IRADIUS(4)  = 0.032
P_IRADIUS(5)  = 0.032
P_IRADIUS(6)  = 0.032
P_IRADIUS(7)  = 0.032
P_IRADIUS(8)  = 0.040
P_IRADIUS(9)  = 0.048
P_IRADIUS(10) = 0.054

! set data for BEAM188 element
*DO, I, 1, P_NRADII
        *IF, P_IRADIUS(I), EQ, 0, THEN
        SECTYPE, I, BEAM, CSOLID
        SECDATA, P_ORADIUS(I)/2, 8, 8
        *ELSE
        SECTYPE, I, BEAM, CTUBE
        SECDATA, P_IRADIUS(I)/2, P_ORADIUS(I)/2
        *ENDIF
*ENDDO

! == 1.4 == prepare data for MASS21 elements
! set element type
ET, 2, MASS21
KEYOPT, 2, 1, 0
KEYOPT, 2, 2, 0
KEYOPT, 2, 3, 0

! prepare element nodes and real numbers
P_NMASSES = 1

P_MASS_REAL= 1

! real constants for MASS21 elements
! Mxx, Myy, Mzz, Ixx(polar moment of inertia), Iyy(diameter moment of inertia), Izz(polar moment of inertia)

! impeller & nut
R, P_MASS_REAL, 4, 4, 4, 1.3e-2, 8.32e-3, 8.32e-3
P_MASS_NODE= 3

! == 1.5 == prepare data for COMBI14 elements
! set element type for bearings/seals
ET, 11, COMBIN14
KX = 1.e+5         !Example stiffness value
KEYOPT,11,,1,0       ! X direction

! prepare element nodes and real numbers
P_NBEARINGS =2

*DIM, P_BEARING_REAL_X, ARRAY, P_NBEARINGS
*DIM, P_BEARING_NODE_X, ARRAY, P_NBEARINGS, 2

P_BEARING_REAL_X(1) = 21
P_BEARING_REAL_X(2) = 22
! set real constants and node ids for bearings/seals
R, P_BEARING_REAL_X(1), KX
P_BEARING_NODE_X(1, 1) = 2
P_BEARING_NODE_X(1, 2) = 1000

R, P_BEARING_REAL_X(2), KX
P_BEARING_NODE_X(2, 1) = 10
P_BEARING_NODE_X(2, 2) = 9000


! node list for the rotor
N, 1,  0.00
N, 2,  0.04
N, 3,  0.08
N, 4,  0.11
N, 5,  0.185
N, 6,  0.251
N, 7,  0.351
N, 8,  0.389
N, 9,  0.415
N, 10, 0.441
N, 11, 0.467

! node list for the bearings/seals
N, 1000, 0.04
N, 1001, 0.04
N, 1002, 0.04
N, 1003, 0.04
N, 1004, 0.04

N, 9000,0.441
N, 9001,0.441
N, 9002,0.441
N, 9003,0.441
N, 9004,0.441

! == 1.6 == elements creation

! rotor elements
TYPE, 1
MAT,  1
*DO, I, 1, P_NRADII
        SECNUM, I
        E, I, I+1
*ENDDO

! mass elements
TYPE, 2
REAL, P_MASS_REAL
E, P_MASS_NODE

! bearing elements
TYPE, 11
*DO, I, 1, P_NBEARINGS
        REAL, P_BEARING_REAL_X(I)
        E, P_BEARING_NODE_X(I,2), P_BEARING_NODE_X(I,1)
*ENDDO


分段运行最后一段报错，错误代码：Element 12 does not have all of its required nodes defined.  The E
command is aborted.
谢谢大家

htbbzzg

  你的弹簧单元只设置了 keyopt(1)，没有设置 keyopt(2) 和 keyopt(3)，因此无法确定弹簧单元的方向，无法定义。  需要仔细看一下帮助文件中有关  combin14 的内容。