主轴模态分析，无法添加轴承弹簧单元
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
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。
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