在ANSYS中如何对节点进行耦合Coupling操作？
2015-10-09 08:53阅读：
在ANSYS中如何对节点进行耦合Coupling操作？
一、
ANSYS中同一节点同一方向不能在2个耦合集中出现
2D螺旋桩土模型，下图绿色圆圈内的节点属于水平线与竖向线的交点，在之前的操作中，分别对水平线和竖向线施加了节点耦合命令（CPINTF,ALL），在求解时程序提示
绿色圆圈内的节点在同一方向（如UX)属于2个耦合集，导致计算不能继续进行。
二、理论基础
1、ANSYS HELP 文件位置
2、
What Is Coupling?
When you need to force two or more degrees of freedom
(DOFs) to take on the same (but unknown) value, you can couple
these DOFs together. A set of coupled
DOFs contains
a prime
DOF, and one or more other DOFs.
Coupling will cause only the prime DOF to be retained in your
analysis' matrix equations, and will cause
all the other DOFs in a coupled set to be
eliminated. The value calculated for the prime DOF will then
be
assigned to all the other DOFs in a
coupled set.
Typical applications for coupled DOFs include: 1) maintaining
symmetry on partial models, 2) forming pin, hinge, universal, and
slider joints between two coincident nodes, and 3)
forcing portions of your model to behave as rigid
bodies (see this chapter's discussion of constraint
equations for more general rigid region capability).
三、
对节点进行耦合的操作方法 1、
How to Create
Coupled Degree of Freedom Sets You can use several
different methods to create a coupled degree-of-freedom set. These
include the CP
command and other
commands such as CPNGEN,
CPINTF,CPLGEN,
and CPSGEN.
These methods of generating coupled sets are discussed in the
following sections.
In addition to the methods discussed here, you can use the
internal multipoint constraint (MPC) feature
of certain contact elements (
CONTA171,
CONTA172,
CONTA173,
CONTA174,
CONTA175,
CONTA176,
and
CONTA177)
to model coupling constraints. By this method, the program builds
MPC equations internally based on the contact kinematics. See
Multipoint
Constraints and Assemblies in the
Contact
Technology Guide for more information on how to use
this feature.
2、
Command(s):
CP
After creating a coupled set of nodes, you can include
more nodes in that set by simply performing an additional coupling operation (be sure to use
the same set reference number). You can also use selecting logic to
couple 'ALL' of the selected nodes. Nodes can be deleted from a coupled set by inputting them as
negativenode
numbers on the CP
command. To modify a
coupled DOF set (that is, add or
delete nodes, or change the DOF label), use the
CPNGEN
command. (You cannot
access the CPNGEN
command directly in
the GUI.)
3、
Command(s):
CPINTF
The CPINTF
command couples
coincident nodes in a model by
generating one coupled set for each specified DOF label at every
pair of coincident nodes. This operation is useful 3'buttoning'
together several pairs of nodes (such as at a
seam).
Instead of coupling coincident nodes, you can use one of
these alternative methods to force the nodes to behave in the same
way:
- If all
DOFs are to be coupled for coincident nodes, it
is usually more efficient to simply merge those nodes together by
using the NUMMRG
command (Main Menu>
Preprocessor> Numbering Ctrls> Merge
Items).
- You can connect coincident pairs of nodes by creating 2-node
elements between them by using the EINTF
command (Main Menu>
Preprocessor> Modeling> Create> Elements> Auto
Numbered> At Coincid Nd).
- To tie together two regions having dissimilar mesh patterns,
use the CEINTF
command (Main Menu>
Preprocessor> Coupling/Ceqn> Adjacent
Regions). This operation generates constraint
equations that connect the selected nodes of one region to the
selected elements of the other region
三、解决方法 1、
使用CPINTF命令
以上图为例，在完成水平线节点的耦合操作后，选择竖向线上的节点，并剔除公用节点，在使用CPINTF,ALL命令即可。
2、节点合并
NUMMRG
3、
multipoint constraint (MPC) approach
You can use the internal multipoint constraint (MPC) approach
(KEYOPT(2) = 2), in
conjunction with certain bonded and no separation contact
definitions (KEYOPT(12) = 4, 5, or 6), to define various contact
assemblies and kinematic constraints. This capability is available
for contact elements CONTA171,
CONTA172,CONTA173,
CONTA174,
CONTA175,
CONTA176,
and CONTA177.
By this method, the program builds MPC equations internally based
on the contact kinematics. You can use this method to model the
following contact assemblies and surface-based
constraints:
- Solid-solid assembly - both contact and target surfaces paste
onto solid element faces
